GST Calculator

To add GST: GST Amount = Base Price × (GST Rate / 100). Total Price = Base Price + GST Amount. To remove GST from an inclusive price: Base Price = Total Price / (1 + GST Rate / 100). GST Amount = Total Price − Base Price. Our calculator does both instantly — just toggle between "Add GST" and "Remove GST."

A reverse GST calculation works backwards from a tax-inclusive total to recover the base price. The GST calculation formula for this is Base = Total / (1 + Rate/100), and the tax component is then GST = Total − Base. For example, at 18% a ₹1,180 inclusive price gives a base of ₹1,000 and GST of ₹180. Switch the toggle above to "Remove GST" and this reverse GST calculator does the back calculation instantly, showing the base, the tax, and the CGST and SGST split to the exact paise.

No — this tool calculates the tax on an invoice, not the penalties on a delayed return. Those are separate charges: under Section 50 of the CGST Act, delayed GST payment attracts interest at 18% per annum on the outstanding amount, calculated from the day after the due date until payment. Late filing additionally attracts a late fee, commonly ₹50 per day for returns with tax payable and ₹20 per day for NIL returns, subject to the prescribed cap. Use this calculator for the invoice tax, then compute interest and late fees separately on the amount it gives you.

Yes, this is a 100% free online GST calculation tool offering faster processing and exact paise precision compared to standard portals like TaxAdda. There is no sign-up, no usage limit, and every figure — base, total, CGST and SGST — is shown to two decimal places rather than rounded to whole rupees, which matters when you are reconciling an invoice.