Reverse GST Calculator — Remove GST From Any Price
Got a price that already includes GST and need to know the base amount? Divide by (1 + rate) — or just type it below. Updated for the GST 2.0 slabs (5%, 18%, 40%) that replaced the old 12% and 28% rates in September 2025. Useful for checking invoices, claiming input tax credit, expense reports, and verifying a seller charged the right rate.
🔄 Remove GST From a Price
Formula: Base = Inclusive price ÷ (1 + GST rate). GST = Inclusive − Base.
Reverse GST Formula
To extract the base price from a GST-inclusive amount:
Base price = Inclusive price ÷ (1 + GST rate) and GST amount = Inclusive price − Base price
Example: an invoice total of ₹11,800 at 18% GST → base = 11,800 ÷ 1.18 = ₹10,000, GST = ₹1,800. A common mistake is multiplying the inclusive price by 18% (₹2,124) — that overstates the tax, because GST was charged on the base, not on the total.
Quick Reference: Divisors for 2026 Rates
| GST rate | Divide inclusive price by | GST share of inclusive price |
|---|---|---|
| 3% (gold) | 1.03 | 2.913% |
| 5% | 1.05 | 4.762% |
| 18% | 1.18 | 15.254% |
| 40% | 1.40 | 28.571% |
When You Need a Reverse GST Calculation
- Input tax credit (ITC): businesses claiming ITC need the exact GST portion of composite or inclusive invoices.
- Expense claims: employers often reimburse pre-tax amounts and need the GST separated.
- Price verification: check whether a seller's "GST included" price actually applied the correct post-GST-2.0 slab — many price lists still silently assume the abolished 12% and 28% rates.
- MRP analysis: MRP in India always includes GST. Reverse-calculating shows the dealer's pre-tax value.