GST calculator guide
What is a GST Calculator?
A GST Calculator works out the Goods and Services Tax on any transaction. You enter the amount and select the applicable GST rate. The calculator then shows the tax amount, the CGST and SGST (or IGST) split, and the final price inclusive of tax. Many calculators also work in reverse — if you know the final price, they can extract the base amount and the tax embedded in it.
GST is India’s unified indirect tax, introduced on 1 July 2017. It replaced a fragmented system of VAT, excise duty, service tax and other levies with a single tax on the supply of goods and services. The tax is collected at every stage of the supply chain, but input tax credit ensures that businesses only pay tax on the value they add, not on the full price of every purchase.
The output is a mathematical result based on the rate you select. GST rates and classifications are governed by the GST Council and can change. Always verify the applicable rate for your specific goods or services on the official GST portal or with a tax professional.
What this calculator shows you
- Base amount — the price before GST.
- GST amount — the total tax charged at the applicable rate.
- CGST and SGST — the central and state components for intra-state transactions.
- IGST — the integrated tax for inter-state transactions.
- Final amount — base amount plus GST, i.e., the invoice value.
- Reverse calculation — base amount and GST extracted from a GST-inclusive price.
- Rate comparison — see how the final amount changes across different GST slabs.
Tip: When you buy from a shop within your state, the invoice shows CGST and SGST separately. When you buy from another state, it shows a single IGST amount. The total tax is the same in both cases for the same rate. The split matters for input tax credit, not for your out-of-pocket cost.
How to use the GST calculator
- Enter the base amount (the price before GST), or the final amount if you want to work backwards.
- Select the applicable GST rate — 0%, 5%, 18% or 40% under the current GST 2.0 structure.
- Choose whether the amount you entered is inclusive or exclusive of GST.
- Select whether the transaction is intra-state (CGST + SGST) or inter-state (IGST).
- Read the GST amount, the component split and the final amount.
- For invoicing, use the CGST and SGST figures separately if the supply is intra-state.
- If you are comparing rates, change the slab and see how the tax amount moves.
GST formulas
GST-exclusive amount (base price known):
GST Amount = Base Amount × GST Rate / 100
Final Amount = Base Amount + GST Amount
GST-inclusive amount (final price known):
GST Amount = Final Amount − [Final Amount × 100 / (100 + GST Rate)]
Base Amount = Final Amount − GST Amount
Example: A product priced at ₹1,000 with 18% GST. GST amount = 1000 × 18 / 100 = ₹180. Final amount = ₹1,180. If the final amount is ₹1,180 and you want the base, GST amount = 1180 − (1180 × 100 / 118) = 1180 − 1000 = ₹180. Base amount = ₹1,000.
CGST, SGST and IGST: the difference
India follows a dual GST model. The Centre and the States both levy tax on the same transaction. The type of tax depends on whether the supply is within a state or between states.
Tax type
When it applies
Who collects it
Rate for an 18% slab
CGST
Intra-state supply (within the same state)
Central Government
9%
SGST
Intra-state supply (within the same state)
State Government
9%
IGST
Inter-state supply (between states)
Central Government
18%
UTGST
Intra-union territory supply
Union Territory
9%
IGST is simply the sum of CGST and SGST/UTGST. For an 18% slab, an intra-state sale attracts 9% CGST plus 9% SGST, while an inter-state sale attracts 18% IGST. The total tax burden is identical. The difference is in how the revenue is shared between the Centre and the destination state.
GST rate structure (GST 2.0, effective 22 September 2025)
The 56th GST Council meeting on 3 September 2025 approved a major rationalisation of GST rates. The earlier four-tier structure of 5%, 12%, 18% and 28% was simplified into two main slabs of 5% and 18%, with a special 40% rate for demerit and luxury goods. The 12% slab was largely absorbed into 5% or 18%, and the 28% slab was merged into 18% or the new 40% rate. The compensation cess on most products was also withdrawn.
GST rate
Category
Common examples
CGST + SGST split
0%
Nil / Exempt
Fresh fruits and vegetables, milk, paneer, 33 life-saving drugs, health and life insurance premiums, educational materials, medical oxygen
0% + 0%
5%
Merit Rate
Packaged foods, medicines, daily essentials, EVs, agricultural supplies, renewable energy equipment, handicrafts, bicycles, tractors, dairy products
2.5% + 2.5%
18%
Standard Rate
Electronics, ACs, TVs, fridges, washing machines, cement, small cars (under 4m), motorcycles (under 350cc), IT services, restaurants, most goods and services
9% + 9%
40%
Sin / Luxury Rate
Pan masala, gutkha, chewing tobacco, cigarettes, aerated and caffeinated beverages, premium luxury vehicles, yachts, personal aircraft, casinos, online money gaming, betting
20% + 20%
Rates effective from 22 September 2025. For official information, visit the GST Portal by the Government of India. Some goods, such as petroleum products, alcohol for human consumption and stamp duty items, remain outside GST.
What changed in the GST 2.0 reforms
- 12% and 28% slabs removed. Most items previously at 12% moved to 5%, and most at 28% moved to 18% or 40%.
- New 40% slab introduced for tobacco, pan masala, aerated drinks, luxury vehicles, casinos, online gaming and similar demerit goods.
- Compensation cess withdrawn on most products. Tobacco products continue to be governed by separate notifications.
- Health and life insurance premiums for individuals are now at Nil GST.
- 33 life-saving medicines moved to Nil GST, and certain cancer and rare-disease medicines reduced from 12% to 5%.
- Daily essentials reduced — hair oil, shampoo, toothpaste, soap, dairy products, namkeens and baby products moved from 18% or 12% to 5%.
- Small cars and motorcycles under the specified engine capacity moved from 28% to 18%.
- Electronics and consumer durables such as air conditioners and large televisions moved from 28% to 18%.
- Agricultural equipment such as tractors moved from 12%–18% to 5%.
GST registration threshold
Not every business needs to register for GST. Registration is mandatory once turnover crosses the threshold limit, which depends on the type of supply and the state.
Type of supplier
Normal category states
Special category states
Supplier of goods
₹40 lakh annual turnover
₹20 lakh annual turnover
Supplier of services
₹20 lakh annual turnover
₹10 lakh annual turnover
Registration is also mandatory in certain cases regardless of turnover — for inter-state supplies, for e-commerce operators, for casual taxable persons, and for those liable to pay under reverse charge. A simplified registration scheme under Rule 14A allows small taxpayers with monthly output tax liability up to ₹2.5 lakh on B2B supplies to register with lighter compliance.
Input Tax Credit (ITC): the core of GST
Input Tax Credit is the mechanism that prevents tax-on-tax (cascading). When a registered business buys goods or services for use in its business, it can offset the GST paid on those purchases against the GST it owes on its own sales. The net amount is what it deposits with the government.
Example:
A manufacturer buys raw material for ₹1,00,000 plus 18% GST = ₹18,000.
It sells finished goods for ₹1,50,000 plus 18% GST = ₹27,000.
GST payable to government = ₹27,000 − ₹18,000 = ₹9,000.
The ₹18,000 paid on purchases is the ITC. Without ITC, the manufacturer would pay the full ₹27,000.
To claim ITC, the buyer must be registered, must possess a valid tax invoice, must have received the goods or services, and the supplier must have paid the tax to the government. The credit must also appear in the buyer’s GSTR-2B. ITC cannot be claimed on personal purchases, on goods used for personal purposes, or where depreciation has been claimed on the tax component of a capital asset.
Illustrative examples
Sample calculations. Your actual tax depends on the rate applicable to your goods or services.
Base amount
GST rate
GST amount
CGST + SGST
Final amount
₹1,000
5%
₹50
₹25 + ₹25
₹1,050
₹1,000
18%
₹180
₹90 + ₹90
₹1,180
₹1,000
40%
₹400
₹200 + ₹200
₹1,400
₹10,000
18%
₹1,800
₹900 + ₹900
₹11,800
₹1,00,000
5%
₹5,000
₹2,500 + ₹2,500
₹1,05,000
For inter-state supplies, replace the CGST + SGST column with a single IGST figure equal to the GST amount.
How to read the result
- Base amount — the price before tax. This is what the seller actually earns before remitting GST.
- GST amount — the tax on the transaction. For a business, this is the output tax liability.
- CGST and SGST — the split for intra-state supplies. Each is half the total rate. The seller must remit both components separately.
- IGST — the single tax for inter-state supplies. It equals CGST + SGST and is remitted to the Centre, which then shares the SGST portion with the destination state.
- Final amount — the invoice value. For a consumer, this is the out-of-pocket price.
- Effective tax rate — the GST amount as a percentage of the base. This is simply the slab rate you selected.
GST vs previous indirect tax system
Feature
Pre-GST
Post-GST
Taxes
VAT, excise, service tax, CST, octroi and more
Single GST with CGST, SGST and IGST components
Cascading
Tax on tax due to limited credit
Full ITC chain across the supply chain
Inter-state trade
CST was a cost with no credit
IGST with full credit
Compliance
Multiple returns and forms per tax
Unified returns under one law
Destination principle
Origin-based in many cases
Consumption-based; tax accrues to destination state
GST eliminated the cascading effect and created a common national market. For businesses, it reduced the number of tax authorities and simplified inter-state trade. For consumers, it brought transparency — the tax is now visible on every invoice.
Common mistakes to avoid
- Applying the wrong rate. GST rates depend on the exact classification of the goods or services. A small difference in description can change the rate.
- Confusing inclusive and exclusive amounts. If a price is ₹1,180 inclusive of 18% GST, the base is ₹1,000, not ₹1,180.
- Adding CGST and SGST to the base twice. The total GST rate is the sum of the two. For an 18% slab, CGST is 9% and SGST is 9%, not 18% each.
- Assuming ITC is always available. Blocked credits, personal use, and non-payment by the supplier can make credit ineligible.
- Forgetting that some items are outside GST. Petroleum products, alcohol for human consumption and stamp duty items are not under GST.
- Not checking the rate for your specific HSN or SAC code. The slab alone is not enough; the classification determines the rate.
- Using old rates after the GST 2.0 transition. The 12% and 28% slabs have been removed. Verify the current rate for your item.
- Ignoring place of supply rules. Whether a transaction is intra-state or inter-state depends on the place of supply, not just the location of the buyer and seller.
Frequently asked questions
What is GST?
GST (Goods and Services Tax) is India’s unified indirect tax on the supply of goods and services. It replaced multiple taxes such as VAT, excise duty, service tax and CST. It is a destination-based, multi-stage value-added tax with input tax credit at every stage.
What are the current GST rates?
Under the GST 2.0 structure effective from 22 September 2025, the main rates are 0% (nil/exempt), 5% (merit rate), 18% (standard rate) and 40% (sin/luxury goods). The earlier 12% and 28% slabs have been removed.
What is the difference between CGST, SGST and IGST?
CGST and SGST are levied on intra-state supplies, each at half the total GST rate. IGST is levied on inter-state supplies at the full rate. IGST is equal to CGST plus SGST. The total tax burden is the same; only the collection and sharing mechanism differs.
How do I calculate GST on an inclusive amount?
Use the formula: GST Amount = Final Amount − [Final Amount × 100 / (100 + GST Rate)]. For example, ₹1,180 inclusive of 18% GST gives GST = 1180 − (1180 × 100 / 118) = ₹180. The base is ₹1,000.
Who needs to register for GST?
Suppliers of goods with annual turnover above ₹40 lakh (₹20 lakh in special category states) and suppliers of services with turnover above ₹20 lakh (₹10 lakh in special category states) must register. Registration is also mandatory for inter-state supplies and e-commerce operators regardless of turnover.
What is input tax credit?
ITC is the mechanism that allows a registered business to offset the GST paid on its purchases against the GST it owes on its sales. This prevents cascading and ensures tax is only on the value added. To claim ITC, you need a valid tax invoice, the goods or services must be received, and the supplier must have paid the tax.
Is GST charged on the base price or the final price?
GST is charged on the base price (the value of supply). The final price is base plus GST. When a price is quoted as inclusive, the GST is extracted from the final price using the reverse formula.
What items are outside GST?
Petroleum crude, petrol, diesel, natural gas, aviation turbine fuel, alcohol for human consumption and stamp duty items are outside GST. They continue to be taxed under the earlier regime.
How has GST 2.0 changed things for consumers?
Many everyday items such as hair oil, shampoo, soap, toothpaste, dairy products, namkeens, tractors and small cars have become cheaper due to rate reductions. Health and life insurance premiums are now at Nil GST. Luxury and sin goods are taxed at 40%. The overall weighted average GST rate has come down.
Can I claim ITC on all purchases?
No. ITC is not available on personal purchases, on goods used for personal purposes, on capital assets where depreciation is claimed on the tax component, and on certain blocked credits specified in Section 17(5) of the CGST Act.
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Checklist for GST calculation
- Correct base amount or final amount identified
- Applicable GST rate confirmed from HSN/SAC classification
- Intra-state or inter-state transaction determined
- CGST and SGST split verified for intra-state supplies
- IGST applied for inter-state supplies
- ITC eligibility checked for business purchases
- Current rate verified after GST 2.0 transition
- Invoice prepared with correct tax components
- GST portal checked for official rate notifications
Disclaimer: This GST calculator and the content on this page are for education and mathematical estimation only. They are not tax advice, a substitute for professional consultation, or a legal opinion. GST rates, classifications, registration thresholds, input tax credit rules and compliance requirements are governed by the CGST Act, 2017, the IGST Act, 2017 and notifications issued by the GST Council. Rates and provisions change from time to time. The GST 2.0 rates mentioned are effective from 22 September 2025, but individual goods and services may have specific rates or exemptions. Always verify the applicable rate for your specific goods or services on the official GST portal or with a qualified chartered accountant before invoicing, filing or making any business decision. Harshonomics is not a tax authority, a GST practitioner, or a legal adviser.
GST calculator guide
What is a GST Calculator?
A GST Calculator works out the Goods and Services Tax on any transaction. You enter the amount and select the applicable GST rate. The calculator then shows the tax amount, the CGST and SGST (or IGST) split, and the final price inclusive of tax. Many calculators also work in reverse — if you know the final price, they can extract the base amount and the tax embedded in it.
GST is India’s unified indirect tax, introduced on 1 July 2017. It replaced a fragmented system of VAT, excise duty, service tax and other levies with a single tax on the supply of goods and services. The tax is collected at every stage of the supply chain, but input tax credit ensures that businesses only pay tax on the value they add, not on the full price of every purchase.
The output is a mathematical result based on the rate you select. GST rates and classifications are governed by the GST Council and can change. Always verify the applicable rate for your specific goods or services on the official GST portal or with a tax professional.
What this calculator shows you
- Base amount — the price before GST.
- GST amount — the total tax charged at the applicable rate.
- CGST and SGST — the central and state components for intra-state transactions.
- IGST — the integrated tax for inter-state transactions.
- Final amount — base amount plus GST, i.e., the invoice value.
- Reverse calculation — base amount and GST extracted from a GST-inclusive price.
- Rate comparison — see how the final amount changes across different GST slabs.
Tip: When you buy from a shop within your state, the invoice shows CGST and SGST separately. When you buy from another state, it shows a single IGST amount. The total tax is the same in both cases for the same rate. The split matters for input tax credit, not for your out-of-pocket cost.
How to use the GST calculator
- Enter the base amount (the price before GST), or the final amount if you want to work backwards.
- Select the applicable GST rate — 0%, 5%, 18% or 40% under the current GST 2.0 structure.
- Choose whether the amount you entered is inclusive or exclusive of GST.
- Select whether the transaction is intra-state (CGST + SGST) or inter-state (IGST).
- Read the GST amount, the component split and the final amount.
- For invoicing, use the CGST and SGST figures separately if the supply is intra-state.
- If you are comparing rates, change the slab and see how the tax amount moves.
GST formulas
GST-exclusive amount (base price known):
GST Amount = Base Amount × GST Rate / 100
Final Amount = Base Amount + GST Amount
GST-inclusive amount (final price known):
GST Amount = Final Amount − [Final Amount × 100 / (100 + GST Rate)]
Base Amount = Final Amount − GST Amount
Example: A product priced at ₹1,000 with 18% GST. GST amount = 1000 × 18 / 100 = ₹180. Final amount = ₹1,180. If the final amount is ₹1,180 and you want the base, GST amount = 1180 − (1180 × 100 / 118) = 1180 − 1000 = ₹180. Base amount = ₹1,000.
CGST, SGST and IGST: the difference
India follows a dual GST model. The Centre and the States both levy tax on the same transaction. The type of tax depends on whether the supply is within a state or between states.
| Tax type | When it applies | Who collects it | Rate for an 18% slab |
|---|---|---|---|
| CGST | Intra-state supply (within the same state) | Central Government | 9% |
| SGST | Intra-state supply (within the same state) | State Government | 9% |
| IGST | Inter-state supply (between states) | Central Government | 18% |
| UTGST | Intra-union territory supply | Union Territory | 9% |
IGST is simply the sum of CGST and SGST/UTGST. For an 18% slab, an intra-state sale attracts 9% CGST plus 9% SGST, while an inter-state sale attracts 18% IGST. The total tax burden is identical. The difference is in how the revenue is shared between the Centre and the destination state.
GST rate structure (GST 2.0, effective 22 September 2025)
The 56th GST Council meeting on 3 September 2025 approved a major rationalisation of GST rates. The earlier four-tier structure of 5%, 12%, 18% and 28% was simplified into two main slabs of 5% and 18%, with a special 40% rate for demerit and luxury goods. The 12% slab was largely absorbed into 5% or 18%, and the 28% slab was merged into 18% or the new 40% rate. The compensation cess on most products was also withdrawn.
| GST rate | Category | Common examples | CGST + SGST split |
|---|---|---|---|
| 0% | Nil / Exempt | Fresh fruits and vegetables, milk, paneer, 33 life-saving drugs, health and life insurance premiums, educational materials, medical oxygen | 0% + 0% |
| 5% | Merit Rate | Packaged foods, medicines, daily essentials, EVs, agricultural supplies, renewable energy equipment, handicrafts, bicycles, tractors, dairy products | 2.5% + 2.5% |
| 18% | Standard Rate | Electronics, ACs, TVs, fridges, washing machines, cement, small cars (under 4m), motorcycles (under 350cc), IT services, restaurants, most goods and services | 9% + 9% |
| 40% | Sin / Luxury Rate | Pan masala, gutkha, chewing tobacco, cigarettes, aerated and caffeinated beverages, premium luxury vehicles, yachts, personal aircraft, casinos, online money gaming, betting | 20% + 20% |
Rates effective from 22 September 2025. For official information, visit the GST Portal by the Government of India. Some goods, such as petroleum products, alcohol for human consumption and stamp duty items, remain outside GST.
What changed in the GST 2.0 reforms
- 12% and 28% slabs removed. Most items previously at 12% moved to 5%, and most at 28% moved to 18% or 40%.
- New 40% slab introduced for tobacco, pan masala, aerated drinks, luxury vehicles, casinos, online gaming and similar demerit goods.
- Compensation cess withdrawn on most products. Tobacco products continue to be governed by separate notifications.
- Health and life insurance premiums for individuals are now at Nil GST.
- 33 life-saving medicines moved to Nil GST, and certain cancer and rare-disease medicines reduced from 12% to 5%.
- Daily essentials reduced — hair oil, shampoo, toothpaste, soap, dairy products, namkeens and baby products moved from 18% or 12% to 5%.
- Small cars and motorcycles under the specified engine capacity moved from 28% to 18%.
- Electronics and consumer durables such as air conditioners and large televisions moved from 28% to 18%.
- Agricultural equipment such as tractors moved from 12%–18% to 5%.
GST registration threshold
Not every business needs to register for GST. Registration is mandatory once turnover crosses the threshold limit, which depends on the type of supply and the state.
| Type of supplier | Normal category states | Special category states |
|---|---|---|
| Supplier of goods | ₹40 lakh annual turnover | ₹20 lakh annual turnover |
| Supplier of services | ₹20 lakh annual turnover | ₹10 lakh annual turnover |
Registration is also mandatory in certain cases regardless of turnover — for inter-state supplies, for e-commerce operators, for casual taxable persons, and for those liable to pay under reverse charge. A simplified registration scheme under Rule 14A allows small taxpayers with monthly output tax liability up to ₹2.5 lakh on B2B supplies to register with lighter compliance.
Input Tax Credit (ITC): the core of GST
Input Tax Credit is the mechanism that prevents tax-on-tax (cascading). When a registered business buys goods or services for use in its business, it can offset the GST paid on those purchases against the GST it owes on its own sales. The net amount is what it deposits with the government.
Example:
A manufacturer buys raw material for ₹1,00,000 plus 18% GST = ₹18,000.
It sells finished goods for ₹1,50,000 plus 18% GST = ₹27,000.
GST payable to government = ₹27,000 − ₹18,000 = ₹9,000.
The ₹18,000 paid on purchases is the ITC. Without ITC, the manufacturer would pay the full ₹27,000.
To claim ITC, the buyer must be registered, must possess a valid tax invoice, must have received the goods or services, and the supplier must have paid the tax to the government. The credit must also appear in the buyer’s GSTR-2B. ITC cannot be claimed on personal purchases, on goods used for personal purposes, or where depreciation has been claimed on the tax component of a capital asset.
Illustrative examples
Sample calculations. Your actual tax depends on the rate applicable to your goods or services.
| Base amount | GST rate | GST amount | CGST + SGST | Final amount |
|---|---|---|---|---|
| ₹1,000 | 5% | ₹50 | ₹25 + ₹25 | ₹1,050 |
| ₹1,000 | 18% | ₹180 | ₹90 + ₹90 | ₹1,180 |
| ₹1,000 | 40% | ₹400 | ₹200 + ₹200 | ₹1,400 |
| ₹10,000 | 18% | ₹1,800 | ₹900 + ₹900 | ₹11,800 |
| ₹1,00,000 | 5% | ₹5,000 | ₹2,500 + ₹2,500 | ₹1,05,000 |
For inter-state supplies, replace the CGST + SGST column with a single IGST figure equal to the GST amount.
How to read the result
- Base amount — the price before tax. This is what the seller actually earns before remitting GST.
- GST amount — the tax on the transaction. For a business, this is the output tax liability.
- CGST and SGST — the split for intra-state supplies. Each is half the total rate. The seller must remit both components separately.
- IGST — the single tax for inter-state supplies. It equals CGST + SGST and is remitted to the Centre, which then shares the SGST portion with the destination state.
- Final amount — the invoice value. For a consumer, this is the out-of-pocket price.
- Effective tax rate — the GST amount as a percentage of the base. This is simply the slab rate you selected.
GST vs previous indirect tax system
| Feature | Pre-GST | Post-GST |
|---|---|---|
| Taxes | VAT, excise, service tax, CST, octroi and more | Single GST with CGST, SGST and IGST components |
| Cascading | Tax on tax due to limited credit | Full ITC chain across the supply chain |
| Inter-state trade | CST was a cost with no credit | IGST with full credit |
| Compliance | Multiple returns and forms per tax | Unified returns under one law |
| Destination principle | Origin-based in many cases | Consumption-based; tax accrues to destination state |
GST eliminated the cascading effect and created a common national market. For businesses, it reduced the number of tax authorities and simplified inter-state trade. For consumers, it brought transparency — the tax is now visible on every invoice.
Common mistakes to avoid
- Applying the wrong rate. GST rates depend on the exact classification of the goods or services. A small difference in description can change the rate.
- Confusing inclusive and exclusive amounts. If a price is ₹1,180 inclusive of 18% GST, the base is ₹1,000, not ₹1,180.
- Adding CGST and SGST to the base twice. The total GST rate is the sum of the two. For an 18% slab, CGST is 9% and SGST is 9%, not 18% each.
- Assuming ITC is always available. Blocked credits, personal use, and non-payment by the supplier can make credit ineligible.
- Forgetting that some items are outside GST. Petroleum products, alcohol for human consumption and stamp duty items are not under GST.
- Not checking the rate for your specific HSN or SAC code. The slab alone is not enough; the classification determines the rate.
- Using old rates after the GST 2.0 transition. The 12% and 28% slabs have been removed. Verify the current rate for your item.
- Ignoring place of supply rules. Whether a transaction is intra-state or inter-state depends on the place of supply, not just the location of the buyer and seller.
Frequently asked questions
What is GST?
GST (Goods and Services Tax) is India’s unified indirect tax on the supply of goods and services. It replaced multiple taxes such as VAT, excise duty, service tax and CST. It is a destination-based, multi-stage value-added tax with input tax credit at every stage.
What are the current GST rates?
Under the GST 2.0 structure effective from 22 September 2025, the main rates are 0% (nil/exempt), 5% (merit rate), 18% (standard rate) and 40% (sin/luxury goods). The earlier 12% and 28% slabs have been removed.
What is the difference between CGST, SGST and IGST?
CGST and SGST are levied on intra-state supplies, each at half the total GST rate. IGST is levied on inter-state supplies at the full rate. IGST is equal to CGST plus SGST. The total tax burden is the same; only the collection and sharing mechanism differs.
How do I calculate GST on an inclusive amount?
Use the formula: GST Amount = Final Amount − [Final Amount × 100 / (100 + GST Rate)]. For example, ₹1,180 inclusive of 18% GST gives GST = 1180 − (1180 × 100 / 118) = ₹180. The base is ₹1,000.
Who needs to register for GST?
Suppliers of goods with annual turnover above ₹40 lakh (₹20 lakh in special category states) and suppliers of services with turnover above ₹20 lakh (₹10 lakh in special category states) must register. Registration is also mandatory for inter-state supplies and e-commerce operators regardless of turnover.
What is input tax credit?
ITC is the mechanism that allows a registered business to offset the GST paid on its purchases against the GST it owes on its sales. This prevents cascading and ensures tax is only on the value added. To claim ITC, you need a valid tax invoice, the goods or services must be received, and the supplier must have paid the tax.
Is GST charged on the base price or the final price?
GST is charged on the base price (the value of supply). The final price is base plus GST. When a price is quoted as inclusive, the GST is extracted from the final price using the reverse formula.
What items are outside GST?
Petroleum crude, petrol, diesel, natural gas, aviation turbine fuel, alcohol for human consumption and stamp duty items are outside GST. They continue to be taxed under the earlier regime.
How has GST 2.0 changed things for consumers?
Many everyday items such as hair oil, shampoo, soap, toothpaste, dairy products, namkeens, tractors and small cars have become cheaper due to rate reductions. Health and life insurance premiums are now at Nil GST. Luxury and sin goods are taxed at 40%. The overall weighted average GST rate has come down.
Can I claim ITC on all purchases?
No. ITC is not available on personal purchases, on goods used for personal purposes, on capital assets where depreciation is claimed on the tax component, and on certain blocked credits specified in Section 17(5) of the CGST Act.
Related calculators
Related guides
Checklist for GST calculation
- Correct base amount or final amount identified
- Applicable GST rate confirmed from HSN/SAC classification
- Intra-state or inter-state transaction determined
- CGST and SGST split verified for intra-state supplies
- IGST applied for inter-state supplies
- ITC eligibility checked for business purchases
- Current rate verified after GST 2.0 transition
- Invoice prepared with correct tax components
- GST portal checked for official rate notifications
Disclaimer: This GST calculator and the content on this page are for education and mathematical estimation only. They are not tax advice, a substitute for professional consultation, or a legal opinion. GST rates, classifications, registration thresholds, input tax credit rules and compliance requirements are governed by the CGST Act, 2017, the IGST Act, 2017 and notifications issued by the GST Council. Rates and provisions change from time to time. The GST 2.0 rates mentioned are effective from 22 September 2025, but individual goods and services may have specific rates or exemptions. Always verify the applicable rate for your specific goods or services on the official GST portal or with a qualified chartered accountant before invoicing, filing or making any business decision. Harshonomics is not a tax authority, a GST practitioner, or a legal adviser.