How GST Works
Adds GST or reverses GST from an inclusive amount. The calculator uses the visible inputs, applies the formula below, and rounds rupee outputs to whole numbers so the result is easy to read on mobile.
Formula
GST result = validated inputs → formula calculation → rounded Indian result
Inputs used:
- Price
- GST rate
- ModeExample Calculation
India-Specific Assumptions
- Business calculators ignore taxes and fees unless the input explicitly includes them.
- Use invoice/accounting software for statutory filing decisions.
- All rupee results are rounded to whole rupees for readability.
- Inputs are treated as estimates; actual bank, employer, university, insurer, or tax-office calculations may differ.
- The calculator uses Indian formats, slab concepts, and common FY 2025-26 assumptions where relevant.
Common questions
Can this calculator add and reverse GST?
Yes. Use add mode when you know the pre-GST price and reverse mode when the price already includes GST.
Which GST rate should I use?
Use the rate applicable to your product or service, such as 5%, 12%, 18%, or 28%. Check official classification for filing decisions.
Does it split CGST and SGST?
The core result shows total GST. For intrastate invoices, total GST is usually split equally into CGST and SGST.
Can I use this for GST returns?
Use it for quick invoice math only. GST return filing should use your accounting records and official portal data.
Why does reverse GST not equal simple subtraction?
Inclusive GST must be back-calculated because the tax is a percentage of the base value, not of the final price.
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Request a calculator →Disclaimer: This calculator is for general informational and educational purposes only. It is not financial, tax, legal, academic, insurance, or professional advice. Verify important decisions with the relevant official source, employer, bank, university, insurer, or adviser.
Last updated: April 2026