How to Calculate GST on an Indian Invoice (2026 Slabs)

If you send Indian invoices, you will type “GST calculator” more often than any other finance query. The math is not exotic — the mistakes are: using the wrong slab, treating intra-state as IGST, or quoting a tax-inclusive price as if it were exclusive.

Inclusive vs exclusive

  • Exclusive: taxable value × rate = GST. Total = taxable + GST.
  • Inclusive: taxable = total ÷ (1 + rate). GST = total − taxable.

The India GST calculator does both locally for 5 / 12 / 18 / 28 percent. It does not file GSTR-1 for you and it does not know your HSN code.

Calculate GST in the browser

CGST + SGST or IGST breakdown. No account. Nothing stored.

Open GST calculator

CGST/SGST vs IGST

Same state (intra-state): split the rate in half as CGST and SGST. Different states (inter-state): the full rate is IGST. Place of supply is a legal fact, not a slider preference — if you are unsure, ask the CA who files your returns.

A 90-second invoice ritual

  1. Confirm the slab for that HSN/SAC (government rate list, not a blog memory).
  2. Enter the taxable amount, pick the slab, choose inclusive or exclusive.
  3. Copy CGST/SGST or IGST onto the invoice line.
  4. If you take payment via a UPI QR, generate a static code that points at a page or UPI string you control with the QR generator. Do not print an expiring payment-link QR from a random SaaS.

Accuracy limits

Rates, exemptions, and composition-scheme rules change. This guide and calculator are arithmetic helpers for 2026’s common slabs, not professional tax advice. When a notice arrives, your books win — not a browser tab.

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