GST Calculator
Add GST to a price or remove (reverse) GST from a total, split it into CGST/SGST or IGST with 5/12/18/28% presets — plus late-payment interest, late fee and input-tax-credit set-off.
Total GST
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Base amount (excl. GST)
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Total (incl. GST)
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- CGST ₹0
- SGST ₹0
Base vs GST
- Base amount ₹0
- GST ₹0
- Total ₹0
How to calculate GST
There are two everyday GST calculations, and this tool does both:
- Adding GST (to a pre-tax price): GST = amount × rate ÷ 100, and total = amount + GST. So ₹10,000 at 18% = ₹1,800 GST and ₹11,800 total.
- Removing / reverse GST (from a GST-inclusive price or MRP): base = total ÷ (1 + rate ÷ 100), and GST = total − base. So ₹11,800 including 18% GST = ₹10,000 base + ₹1,800 GST.
CGST, SGST and IGST split
The total GST is the same whether a sale is within a state or across states — only the split changes. For an intra-state supply, GST is divided equally into CGST and SGST (18% = 9% + 9%). For an inter-state supply, the entire amount is charged as IGST. Toggle the supply type above to see the correct breakup on your invoice.
GST rate slabs & the GST percentage
India uses four main GST slabs — 5%, 12%, 18% and 28% (for example, 18 percent GST on most services) — plus 0% for many essentials and special rates for a few goods. Use the presets above for the common rates or type any custom rate. To find the GST percentage from a bill, divide the GST amount by the base amount and multiply by 100 — so ₹180 GST on a ₹1,000 base is 18 percent. You can also download any result as a CSV that opens in Excel, or print it as a PDF.
Late payment: interest and late fee
File or pay after the due date and two charges apply: interest at 18% per year on the net tax (24% on wrongly availed ITC), plus a late fee of ₹50 per day (₹20 for nil returns), capped by turnover. The interest & late-fee section above estimates both.
Input tax credit set-off
ITC set-off decides how your input credit reduces your output liability. IGST credit is used first (against IGST, then CGST, then SGST); CGST credit against CGST then IGST; SGST credit against SGST then IGST — and CGST can never offset SGST or vice versa. Getting the order right minimises the cash you actually pay, which the set-off section works out for you. Running a business? See our income tax calculator too.
Frequently asked questions
How do you calculate GST on an amount?
To add GST to a pre-tax (exclusive) amount: GST = amount × rate ÷ 100, and total = amount + GST. For example, ₹1,000 at 18% GST gives ₹180 GST and a total of ₹1,180. This calculator does it both ways — add GST to a base price, or remove GST from a GST-inclusive price.
What is reverse GST (removing GST from a total)?
Reverse GST extracts the tax from a GST-inclusive price. Base amount = total ÷ (1 + rate ÷ 100), and GST = total − base. For example, from ₹1,180 including 18% GST, the base is ₹1,180 ÷ 1.18 = ₹1,000 and the GST is ₹180. Switch this calculator to "Remove GST" to do exactly that.
What is the difference between CGST, SGST and IGST?
For a supply within the same state (intra-state), GST is split equally into CGST (central) and SGST (state) — so 18% becomes 9% CGST + 9% SGST. For a supply between two states (inter-state), the whole tax is charged as IGST. The total GST is the same either way; only the split differs. Choose intra- or inter-state above to see the correct split.
What are the GST rate slabs in India?
The main GST slabs are 5%, 12%, 18% and 28%, with 0% (nil-rated) for many essentials and special rates like 0.25% and 3% for items such as rough diamonds and gold. 18% is the most common rate for services and many goods. Use the rate presets above or type a custom rate.
How is interest on late GST payment calculated?
Interest is charged at 18% per annum on the net tax paid late, calculated for the number of days from the due date until you pay: interest = tax × 18% × days ÷ 365. (Interest on wrongly availed and utilised input tax credit is 24%.) The interest and late-fee section above computes this for you.
What is the GST late fee for filing returns late?
The late fee is ₹50 per day (₹25 CGST + ₹25 SGST) for a normal return and ₹20 per day (₹10 + ₹10) for a nil return, subject to a maximum cap that depends on turnover. This calculator applies ₹50/₹20 per day up to the common ₹5,000 cap so you can estimate the fee quickly.
What is GST set-off (input tax credit utilisation)?
Set-off is the order in which your input tax credit (ITC) reduces your output GST liability. IGST credit must be used first — against IGST, then CGST, then SGST. CGST credit is used against CGST then IGST; SGST credit against SGST then IGST. Crucially, CGST credit can never offset SGST liability, or vice versa. The set-off section above applies these rules and shows the cash you still need to pay.
How do I calculate GST on MRP?
MRP (maximum retail price) is inclusive of GST, so use reverse GST: base = MRP ÷ (1 + rate ÷ 100). For an MRP of ₹500 at 18%, the pre-tax value is ₹500 ÷ 1.18 = ₹423.73 and the GST component is ₹76.27. Set this calculator to "Remove GST" and enter the MRP.
How do I calculate the GST percentage?
To find the GST percentage from a bill, divide the GST amount by the base (pre-tax) amount and multiply by 100: GST % = GST ÷ base × 100. For example, ₹180 GST on a ₹1,000 base is ₹180 ÷ ₹1,000 × 100 = 18 percent. If you only know the inclusive total, first remove GST to get the base, then apply the same formula.
How do I calculate GST in Excel?
In Excel or Google Sheets, to add GST use =base*rate (e.g. =A2*18% gives the GST) and =base*(1+rate) for the total. To remove/reverse GST from an inclusive amount use =total/(1+rate) for the base and =total-base for the GST. This calculator does the same instantly and lets you download the breakdown as a CSV file that opens directly in Excel.
Sources & methodology
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