After You Calculate
Use the free invoice generator to turn the calculation into a draft bill, then review the final details before sending it.
Use this calculator when you need to add GST to a base amount or remove GST from a final amount. It helps you check tax values quickly before raising an invoice or quotation.
This calculator is an independent working aid for estimation and checking. It is not an official GST portal or tax-advice service. Verify rates and invoice requirements against current official guidance when the result affects compliance work.
Need help applying the result? Read GST calculator online for small business, then review how to calculate profit margin before you send the final document.
If GST is added on top of the base amount, tax is calculated on the base value. If the amount already includes GST, the tax portion is separated from the total using the selected GST rate.
The most common GST slabs are 5%, 12%, 18%, and 28%. Some goods may fall under special rates such as 0%, 0.25%, or 3%.
CGST and SGST usually apply to sales within the same state. IGST is generally used for inter-state sales and imports.
Yes. You can use the calculator without payment or sign-up.
Calculation method
The calculator uses simple arithmetic formulas for tax-exclusive and tax-inclusive amounts. It does not decide whether a product or service qualifies for a specific GST rate; you choose the rate and the tool calculates the breakup.
Add GST
GST = Base Amount x Rate / 100
Total = Base Amount + GST
Use this when your quote or price does not include GST yet.
Remove GST
GST = Total x Rate / (100 + Rate)
Base = Total - GST
Use this when the price already includes GST and you need the tax portion.
If a service is priced at Rs 10,000 before tax and you select 18% GST, the GST amount is Rs 1,800 and the total becomes Rs 11,800. For an intra-state supply, that Rs 1,800 is commonly split as Rs 900 CGST and Rs 900 SGST. For an inter-state supply, it is commonly shown as Rs 1,800 IGST.
If Rs 11,800 already includes 18% GST, the taxable value is Rs 10,000 and the GST portion is Rs 1,800. This reverse calculation is useful when you receive a GST-inclusive amount from a client or supplier.
Last reviewed: 2 August 2026. This page explains calculation formulas and common invoice workflows. It is not an official GST service and does not replace professional tax advice.
Enter an amount, choose the GST rate, and get the tax breakup instantly. Use it before making an invoice, quotation, or price estimate.
Quick guide
Common rates
5 / 12 / 18 / 28
You get
Base amount, GST amount, and the final total in one view.
Useful for invoices and quotations
Tax Slab (%)
GST @ 18% · Tax Exclusive
Date
September 5, 2026
Intra-state (CGST + SGST)
Inter-state (IGST)
Use this result as a quick check before you raise an invoice, send a quotation, or confirm a tax-inclusive price with a client.