GST Calculator: Add or Remove GST From an Amount

A GST calculator helps you quickly add GST to a taxable amount or remove GST from an amount that already includes tax. This is useful when checking invoice totals, quotation amounts, and product or service prices.

Use the GST Calculator to enter the amount, GST rate, and supply type. The calculator can show taxable value, GST amount, total amount, and the CGST/SGST or IGST split.

Add GST formula

When the entered amount does not include GST:

GST amount = Taxable amount x GST rate / 100

Total amount = Taxable amount + GST amount

For example, if the taxable amount is Rs 10,000 and GST is 18%:

• GST amount = Rs 10,000 x 18%
• GST amount = Rs 1,800
• Total amount = Rs 11,800

Remove GST formula

When the entered amount already includes GST:

Taxable amount = GST-inclusive amount / (1 + GST rate / 100)

GST amount = GST-inclusive amount - taxable amount

For example, if the GST-inclusive amount is Rs 11,800 and GST is 18%:

• Taxable amount = Rs 11,800 / 1.18
• Taxable amount = Rs 10,000
• GST amount = Rs 1,800

CGST and SGST vs IGST

For a same-state supply, GST is commonly split into CGST and SGST. For example, 18% GST becomes 9% CGST and 9% SGST.

For a different-state supply, the full GST amount is commonly shown as IGST. For example, 18% GST is shown as 18% IGST.

If you need to create a GST invoice, try the India GST Invoice Generator. It includes GSTIN, HSN/SAC, CGST/SGST or IGST, records, and PDF printing.

Assumptions

• The calculator uses India-style GST terminology.
• Same-state supply splits GST equally into CGST and SGST.
• Different-state supply shows the full GST as IGST.
• It does not validate HSN/SAC classification, reverse charge, exemptions, composition scheme, input tax credit, or invoice compliance.

Disclaimer

The information and calculations provided on this website are for general informational and educational purposes only. Results are estimates based on user inputs and simplified assumptions and may not reflect actual tax treatment. This content does not constitute tax, legal, accounting, or financial advice. Consult a qualified tax professional or accountant before making business, tax, or filing decisions.

This website is not affiliated with the Income Tax Department of India, GSTN, CBIC, or any government agency.