GST Calculator

How to read this gst calculator

Choose Add GST when the entered price excludes tax, or Remove GST when it includes tax. The selected rate is your assumption; this tool does not determine product classification, eligibility or place-of-supply rules.

Worked example

Adding 18% GST to ₹1,000 produces ₹180 tax and ₹1,180 total. Removing 18% from ₹1,180 recovers the ₹1,000 base.

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Method and assumptions

For a tax-inclusive amount, base = total ÷ (1 + rate). Subtract the base from the total to find GST; simply subtracting 18% from the total would be incorrect.

Add GST to an exclusive base amount or extract it from a GST-inclusive total. Enter the applicable rate for your transaction; this calculator does not determine tax classification. Values are calculated at full precision and displayed to two decimals; invoice rounding may differ.

Checks and limitations

Example and model checked on 2026-09-12. These are software calculation checks, not a professional review of your finances. Displayed rupees may differ slightly from unrounded totals.

This is a mathematical model; it does not quote a specific financial product.

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