GST calculator — on top, or inside

Two questions decide the number: is the price before or after tax, and does the client sit in your state. Answer both; the split follows.

Amount (₹) GST rate Custom rate (%) Amount is Supply

The rules this tool applies

Slabs since 22 September 2025 (GST 2.0): 0%, 5%, 18% and 40% — the 12% and 28% slabs were folded into 5% and 18%; 40% is the de-merit rate (tobacco, pan masala, luxury cars and the like). Professional, IT, design, consulting and most other services are 18%.
Inclusive maths: taxable value = amount ÷ (1 + rate); GST = amount − taxable value. At 18%, an inclusive ₹1,180 contains ₹180 of GST, not ₹212.
Place of supply: client in your state → CGST + SGST (half each); another state or Union Territory → IGST at the full rate. Both add up to the same total.
Exports under LUT: 0% (zero-rated) — no GST on the invoice, ITC still claimable. Without LUT you pay IGST and claim a refund.
Reverse charge: when the recipient pays (e.g. legal services, imports of services), the invoice shows the rate but no tax is collected.

Worked example

Fee ₹50,000, exclusive, 18%, client in another state: IGST ₹9,000, invoice ₹59,000. The same client agrees an all-inclusive ₹50,000: taxable value ₹42,372.88, IGST ₹7,627.12 — you keep ₹42,373, not ₹41,000.

Edge cases to know

Composition dealers cannot charge GST on the invoice — they pay 1% / 5% / 6% out of pocket and issue a bill of supply.
Rounding: s.170 rounds the tax on the invoice to the nearest rupee; this tool keeps paise so you can see the split.
TDS under s.51 (government clients, 2%) and TCS by e-commerce operators are computed on the taxable value, not the GST-inclusive total.
Rate changes follow GST Council notifications, not the Finance Act — check this page after 7 October 2026.

Related tools

SAC / HSN lookup — the code for your invoice.
Export invoice generator — LUT-ready, with SAC and place of supply.
GST: register or not?.

Last verified: 18 September 2026 — Rate structure per GST Council 56th meeting (3 September 2025), Notifications 9/2025 and 10/2025-CT(Rate) effective 22 September 2025; CGST/SGST/IGST split per s.8/s.9 IGST Act. The 57th GST Council meets on 7 October 2026; this page is re-checked after every Council. · GST advice varies with facts — confirm with a CA.