GST calculator for India, done right
Work out GST both ways — add GST to a base amount (exclusive) or extract it from a GST-inclusive total (reverse GST) — with the correct CGST/SGST split for intra-state supply and IGST for inter-state. Every figure is computed in exact paise, and it all runs in your browser: 0 uploads, works offline.
How to use it
- Enter the amount in rupees.
- Pick the GST rate — 0%, 5%, 12%, 18% or 28%.
- Choose whether the amount is exclusive (GST added on top) or inclusive (GST already inside — the reverse calculation).
- Choose intra-state (splits into CGST + SGST) or inter-state (a single IGST).
- Read the breakdown instantly, tap Show the math to see how it's derived, and Copy the result for an invoice or WhatsApp.
FAQ
How do I calculate GST for free without uploading?
Enter the amount and rate on this page — the calculation happens in your browser using local JavaScript, so nothing is uploaded and there's no sign-up. You can verify it: switch on aeroplane mode and it still calculates. It handles both forward (exclusive) and reverse (inclusive) GST and splits CGST/SGST or IGST correctly.
What's the difference between inclusive and exclusive GST?
Exclusive means the amount is the taxable value and GST is added on top. Inclusive means the amount already contains GST, so the tool works backwards to find the taxable value and the tax inside it — often called a reverse GST calculator.
When is it CGST + SGST versus IGST?
For supply within the same state (intra-state), GST is split equally into Central GST (CGST) and State GST (SGST). For supply across states (inter-state), the whole tax is a single Integrated GST (IGST) at the full rate.
Are the amounts accurate to the paisa?
Yes. All arithmetic is done in integer paise (never floating rupees), and CGST/SGST are split so they always add back to the total GST with no paisa lost. The tool ships with a hand-computed test suite covering every rate and both directions.
Does it store my numbers?
No. Nothing you type is uploaded or saved — close the tab and it's gone.
Limits
Covers the standard GST rates (0/5/12/18/28%). It does not add cess (applicable on a few items like tobacco and luxury cars) or handle TCS/TDS — those are separate line items on a return. Rates are the current standard slabs; always confirm the rate that applies to your specific goods or service.
Related
For billing, the invoice generator and amount-in-words tools pair naturally with this calculator once they're live.
Bookmark this page (Ctrl+D, or ⌘D on Mac) or install the app — it works offline the next time you need it.