GST Calculator — what it does
Adds or removes GST on any amount at the Indian 5%, 12%, 18% and 28% slabs, showing the CGST and SGST halves of the central split alongside the total. The reverse calculation is the one people actually need: turning a GST-inclusive price back into a taxable value.
How to use GST Calculator
- Choose whether you are adding GST to a base amount or extracting GST from an inclusive amount.
- Enter the amount and select the slab rate.
- Read the taxable value, the GST amount, the CGST and SGST split, and the total.
- Use the per-slab breakdown when a bill mixes rates — for example a restaurant invoice with food at 5% and packaged items at 12%.
Worked example: extracting GST from a round figure
A customer pays ₹10,000 inclusive of 18% GST. The taxable value is ₹8,474.58 and the tax is ₹1,525.42 — not ₹1,800, which is what you get by multiplying the inclusive amount by 18%. That difference is a real bookkeeping error, and the reverse mode exists to prevent it.
At a glance
| Modes | Add GST to a base amount, or remove GST from an inclusive amount |
|---|---|
| Rates | 5%, 12%, 18%, 28% slabs |
| Split | CGST and SGST shown separately for the 50-50 central split |
| Where it runs | Instantly in the browser, offline after first load |
Frequently asked questions
- What is GST Calculator?
- Add or remove GST on any amount with India's 5/12/18/28% slabs — including the CGST & SGST split. Instant, free and offline.
- Is GST Calculator free to use?
- Yes — GST Calculator is free to use, with no sign-up, no install and no account.
- Does GST Calculator upload or store my data?
- No — GST Calculator runs entirely in your browser, so your text, files and results never leave your device.
- Do I need to install anything to use GST Calculator?
- No — it works in any modern browser (Chrome, Edge, Firefox, Safari) with no downloads, accounts or plugins.
- Is GST always split as CGST and SGST?
- Only for intra-state supplies. Inter-state supplies use IGST instead, where the whole amount goes to the centre. The split shown here is the intra-state case; for inter-state, use the plain total.
- Which rates are current?
- The 5%, 12%, 18% and 28% slabs are the standard structure, but rate changes and per-item classifications change by notification — for anything unusual, confirm the HSN rate on the portal.