Add or remove GST
GST at 5, 18 or 40%, with CGST/SGST split.
Everything runs on your device. No accounts. Free.
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About this tool
Two directions: add GST to a pre-tax amount to see the final price, or start from a tax-inclusive total and extract the base amount and the tax inside it. Quick buttons cover the current 5, 18 and 40 percent slabs, and any custom rate works too if you are calculating an older invoice.
The CGST/SGST split (half and half for intra-state sales) is shown alongside, which is what invoices actually need. Calculated locally, instantly.
How it works
- Enter your numbers and pick the options.
- The result updates live as you type.
- Everything is calculated on your device, nothing is saved or sent.
Frequently asked questions
How do I remove GST from a total that already includes it?
Divide the total by 1 plus the rate. An 1180 rupee bill at 18% GST contains a base of 1180 / 1.18 = 1000 and 180 of tax. Pick 'Remove GST' mode and this happens automatically.
What are CGST and SGST?
For sales within a state, GST is split equally between the centre (CGST) and the state (SGST), so an 18% rate appears on invoices as 9% + 9%. Interstate sales use a single IGST at the full rate instead.
Which GST rates apply to what?
Since the September 2025 rationalisation there are two main slabs: 5% for essentials and 18% as the standard rate for most goods and services, plus a special 40% rate for luxury and sin goods like tobacco and aerated drinks. The older 12% and 28% slabs were removed. Rates change with council decisions, so check the current schedule for your specific item, and type any custom rate for a pre-2025 invoice.
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