| Base amount | ₹0.00 |
| Discount | -₹0.00 |
| Taxable value | ₹0.00 |
| Tax (18%) | ₹0.00 |
| Total | ₹0.00 |
Free GST & invoice calculator for India
Calculate GST in seconds — whether you need to add tax to a base price (exclusive) or extract it from a total (inclusive). Supports all standard Indian GST slabs (5%, 12%, 18%, 28%) plus discounts, making it perfect for freelancers, consultants, and small businesses raising invoices.
Exclusive vs inclusive GST
Add tax (exclusive): your price is before GST, and tax is added on top — the usual way to quote B2B. Extract tax (inclusive): your price already includes GST, and the tool works out how much of it is tax — useful for retail pricing and reconciliation.
Accurate & private
Every figure is calculated instantly in your browser. No amounts, client names, or invoice data are ever sent anywhere — ideal when handling sensitive financial numbers.
The GST slabs changed in September 2025 — make sure you are using the right one
At its 56th meeting on 3 September 2025, the GST Council approved the largest restructuring of the tax since its introduction in 2017, and the revised rates took effect on 22 September 2025. The old four-slab structure of 5%, 12%, 18% and 28% was collapsed into two principal slabs.
The current structure is 0% for nil-rated and exempt supplies, 5% as the merit rate for essentials and everyday goods, 18% as the standard rate for most goods and services, and a new 40% demerit rate for a narrow set of luxury and sin goods such as tobacco products, pan masala, aerated drinks and high-end vehicles. Special rates continue outside this structure, notably 3% on gold, silver and jewellery and 0.25% on rough diamonds. The 12% and 28% slabs were removed: most items at 12% moved down to 5%, and most at 28% moved down to 18%.
This calculator offers the current slabs first, and keeps 12% and 28% available and clearly labelled as legacy, because anyone reconciling invoices, issuing credit notes or amending returns for periods before 22 September 2025 still needs them. Always apply the rate in force on the date of supply, not the date you are doing the arithmetic.
CGST, SGST and IGST: the split most invoices get wrong
GST is one rate but not always one line. For a supply within a single state, the rate is split evenly between CGST (central) and SGST (state), so 18% appears on the invoice as 9% CGST plus 9% SGST. For a supply between states, the whole amount is charged as a single line of IGST. The formula is simply IGST = CGST + SGST, and the customer pays the same total either way — the difference is which government receives it, which is why the split has to be right on the invoice even though it does not change the amount collected.
Exclusive versus inclusive, and the extraction formula
Adding tax to a base price is straightforward: tax = base × rate — 100. Extracting tax from a price that already contains it is where errors happen, because people apply the rate to the gross figure. The correct formula is:
tax = gross − base
Worked example at 18%: a gross of ₹11,800 gives a base of 11,800 × 100 ÷ 118 = ₹10,000 and tax of ₹1,800. Applying 18% to the gross instead would give ₹2,124, overstating the tax by ₹324 on a single invoice. Repeated across a month of billing, that is a reconciliation problem.
Frequently asked questions
What are the current GST rates in India?
Since 22 September 2025 the structure is 0% for nil-rated and exempt supplies, 5% as the merit rate, 18% as the standard rate, and 40% for specified luxury and sin goods. Special rates of 3% on gold, silver and jewellery and 0.25% on rough diamonds continue separately. The 12% and 28% slabs no longer apply to new supplies.
Why does the calculator still offer 12% and 28%?
Because businesses routinely need them for historical work: reconciling invoices raised before 22 September 2025, issuing credit or debit notes against those invoices, and amending earlier returns. They are labelled as legacy so nobody applies them to a current supply by accident.
How do I split GST into CGST and SGST?
Halve the rate. An 18% intra-state supply is 9% CGST plus 9% SGST. For inter-state supplies you do not split at all — the full 18% is charged as IGST on a single line.
How do I remove GST from an inclusive price?
Divide, do not subtract the percentage. Base = gross × 100 ÷ (100 + rate). At 18%, divide the gross by 1.18. Applying the rate directly to the gross figure overstates the tax every time, and the error grows with the rate.
Is this calculator a substitute for professional tax advice?
No. It performs arithmetic on the figures and rate you select. It does not determine which slab your particular goods or services fall into, which is a classification question that depends on HSN or SAC codes and on notifications issued by the GST Council. For classification, place of supply, or input tax credit questions, consult a qualified chartered accountant or GST practitioner.