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GST Calculator
Add or remove India's GST at 5%, 18% or 40% — see the base amount, the GST and the total, for both tax-exclusive and tax-inclusive prices. Runs in your browser.
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Quick Answer
Enter an amount and a GST rate (5%, 18% or 40%) and the calculator splits out the base, the GST and the total. In Add mode it treats your amount as the pre-tax base and adds GST on top; in Remove mode it treats your amount as GST-inclusive and works backwards to the base. The three rates are India's current GST 2.0 slabs — the old 12% and 28% slabs were removed on 22 September 2025. It runs entirely in your browser.
What the GST Calculator Does
Type an amount, pick the GST rate and choose whether to add or remove the tax. Add mode (exclusive) takes your amount as the price before tax and shows the GST and the final total. Remove mode (inclusive) takes your amount as the price that already includes GST and extracts the base price and the tax inside it.
The three preset rates — 5, 18 and 40 percent — are India's current GST slabs after the September 2025 GST 2.0 reform, which replaced the older 5/12/18/28 structure. 5% covers most essentials, 18% is the standard rate for most goods and services, and 40% applies to luxury and sin goods. Pick the one that applies and the calculator handles the arithmetic both ways.
How It Works
In Add mode the GST is the amount times the rate (so 18% of ₹1,000 is ₹180), and the total is the amount plus that GST. In Remove mode the amount already contains the tax, so the base is the amount divided by one-plus-the-rate, and the GST is whatever is left over — the same ₹1,180 inclusive total yields a ₹1,000 base and ₹180 of GST.
The single rate you pick is the combined GST. On an intra-state sale it is split equally into CGST and SGST (so 18% is 9% plus 9%); on an inter-state sale it appears as IGST at the full rate. The total tax is the same either way — the split is about which government collects it.
Methodology
- Read the inputs. Take the amount, the GST rate and the mode (add or remove).
- Add mode. GST is the amount times the rate; the total is the amount plus the GST; the amount itself is the base.
- Remove mode. The base is the amount divided by one-plus-the-rate; the GST is the amount minus the base; the amount itself is the total.
- Show the split. Display the base amount, the GST and the total.
Add and remove GST
Add (exclusive): GST = amount × rate ; total = amount + GST
Remove (inclusive): base = amount ÷ (1 + rate) ; GST = amount − baseWorked example
₹1,000 + 18% GST → ₹180 GST, ₹1,180 total · ₹1,180 inclusive → ₹1,000 base + ₹180 GSTThe rate is the combined GST; intra-state it splits as CGST plus SGST (half each), inter-state it is IGST. The maths is the same for the 5% and 40% slabs — just change the rate.
Assumptions
- A single GST rate applies to the whole amount. A bill with items at different slabs needs each line calculated at its own rate.
- The preset rates are the current GST 2.0 slabs — 5, 18 and 40 percent. Essentials at the 0% nil rate and special rates such as 3% on gold are not in the dropdown; type-agnostic add and remove maths still works if you need another rate elsewhere.
- Compensation cess (still charged on a few items such as tobacco and pan masala) is not added — for those goods the real tax is higher than the slab alone.
- The figure shown is the combined GST. The CGST-plus-SGST or IGST split is not broken out, though the total tax is the same.
- Amounts are rounded to two decimals for display, so a tax invoice may round individual lines slightly differently.
Technical Details
| Modes | add (exclusive) and remove (inclusive) |
|---|---|
| Preset rates | 5, 18, 40 percent (GST 2.0) |
| Outputs | base amount, GST, total |
| Tax split | shows combined GST, not the CGST/SGST split |
| Currency | rupees |
| Cess | not included |
| Where it runs | In your browser — nothing uploaded |
Standards & references
- GST 2.0 slabs (from 22 September 2025) — India simplified its GST to 5%, 18% and 40% (plus a 0% nil rate on essentials), removing the earlier 12% and 28% slabs. A few special rates remain, such as 3% on gold and jewellery. This tool offers the three main slabs — 5, 18 and 40.
- CGST, SGST and IGST — an intra-state sale splits GST equally into Central GST and State GST; an inter-state sale charges Integrated GST at the full rate. The total tax is identical.
- Inclusive vs exclusive — an exclusive price adds GST on top; an inclusive price already contains it. The calculator's Add and Remove modes handle each.
Accuracy & Limitations
The arithmetic is exact for a single rate. Add mode and Remove mode are true inverses — add 18% to ₹1,000 and you get ₹1,180; remove 18% from ₹1,180 and you get back ₹1,000 with ₹180 of tax.
The preset slabs are current: the September 2025 GST 2.0 reform moved most goods to 5% or 18% and introduced a 40% rate for luxury and sin goods, removing the old 12% and 28% slabs. Still confirm which slab your specific item falls in.
It shows the combined GST only. For an invoice you may need to split it into CGST and SGST (half each) for an intra-state sale, or show it as IGST for an inter-state one — the total is unchanged.
Compensation cess is not handled. A few categories, such as tobacco and pan masala, carry an extra cess on top of GST; for those, the calculator understates the total tax.
It applies one rate to the whole amount. A mixed basket — items at different slabs — must be calculated line by line, then summed.
Real-World Use Cases
Invoicing
Add GST to a pre-tax price to show the tax and the final amount.
Checking a bill
Extract the base and the tax from a GST-inclusive total.
Pricing
Work out the listed (inclusive) price from a base, or the base from a listed price.
Quick estimates
See the tax component on a purchase at a given slab.
When to use it — and when not to
Good for
- Adding GST to a pre-tax amount
- Removing GST from an inclusive price
- A single-rate GST split (base, tax, total)
- Quick tax estimates on a purchase
Not the best choice for
- A bill with items at several rates
- Showing the CGST/SGST or IGST split
- Items that also carry a compensation cess
- Confirming which slab currently applies
Need the CGST-plus-SGST breakdown or a full tax invoice? Use accounting or invoicing software. Working out a discount before tax? Use the discount calculator, then add GST here.
Frequently Asked Questions
What is the difference between add and remove mode?
Add (exclusive) treats your amount as the pre-tax base and adds GST on top. Remove (inclusive) treats your amount as already including GST and works backwards to the base price and the tax inside it.
How do I remove GST from a total?
Use Remove mode. The base is the inclusive amount divided by one plus the rate — so ₹1,180 at 18% gives a ₹1,000 base and ₹180 of GST.
What are the current GST rates?
Since the September 2025 GST 2.0 reform, the main slabs are 5%, 18% and 40%, plus a 0% nil rate on essentials. The old 12% and 28% slabs were removed. This tool offers 5, 18 and 40.
Which GST rate should I use?
The one that applies to your product or service — 5% for most essentials, 18% for standard goods and services, and 40% for luxury and sin goods. Confirm your specific item's slab if unsure.
What happened to the 12% and 28% slabs?
They were removed in the GST 2.0 reform effective 22 September 2025. Most 12% items moved to 5% and most 28% items to 18%, while luxury and sin goods moved to a new 40% rate.
What are CGST, SGST and IGST?
For a sale within a state, GST splits equally into Central GST and State GST. For a sale between states it is charged as a single Integrated GST. The total tax is the same; the split decides which government collects it.
Does it show the CGST and SGST split?
No, it shows the combined GST. To split it, halve the figure for CGST and SGST on an intra-state sale, or show the full amount as IGST on an inter-state one.
Is compensation cess included?
No. A few items, such as tobacco and pan masala, carry an extra cess on top of GST. For those, the real tax is higher than the slab the calculator uses.
Can I calculate a bill with different rates?
Not in one go — it applies one rate to the whole amount. Calculate each item at its own rate and add the results together.
What does inclusive of GST mean on a price tag?
It means the displayed price already contains the tax. Use Remove mode to see how much of that price is the base and how much is GST.
Is my data uploaded?
No. The calculation runs entirely in your browser; nothing is sent anywhere.
Does it work for any currency?
The arithmetic does — it is just a percentage. The labels show rupees because GST is an Indian tax, but the add and remove maths is the same for any tax rate.
References
Splits an amount into base, GST and total with exact add (exclusive) and remove (inclusive) modes at the chosen slab. It uses India's current GST 2.0 rates (5, 18 and 40 percent, after the 12% and 28% slabs were removed in September 2025), and is upfront that it shows the combined GST rather than the CGST/SGST split and that compensation cess is not included.
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