What this calculation tells you
GST-inclusive and GST-exclusive amounts use different starting points. If a price already includes tax, simply subtracting the rate from the total does not recover the original base. This tool reverses the percentage correctly.
The rate and supply treatment are inputs, not conclusions from the calculator. We do not determine HSN/SAC classification, place of supply, eligibility for input credit, cess or filing obligations. Verify those independently using current official information or a qualified adviser.
The method, explained
Add: GST = base × rate ÷ 100 Remove: base = inclusive total ÷ (1 + rate ÷ 100) GST amount = inclusive total − base
The inputs use the units printed beside each field. Values shown in result cards are rounded for readability; the calculator keeps more precision while applying the formula.
A worked example
Amount: ₹10,000.00 · GST rate to apply: 18 % · Calculation: Add GST to base amount · Tax split illustration: CGST + SGST.
Amount including GST: ₹11,800.00
This example uses the inputs above. Your result changes when you change them.
Assumptions & limitations
- No tax-rate lookup is performed; the default rate is an arithmetic example.
- The CGST/SGST illustration splits total GST equally. Cess and additional levies are excluded.
- This is not a tax invoice, filing service or determination of tax liability.
Questions about this tool
How do I remove an assumed 18% from ₹1,180 inclusive?
Divide ₹1,180 by 1.18 to get ₹1,000 base. The tax portion is ₹180; do not subtract 18% of ₹1,180.
Will the calculator choose the legal rate?
No. Enter the rate that applies to the relevant supply and transaction date after checking official guidance.
Context checked 30 September 2026. External sources do not endorse this tool.
Published by Sanu Tech Innovation LLP · Model notes updated 30 September 2026. Read our calculation standards or report a reproducible issue.