GST Calculator

How the sum works

Adding GST: GST = amount × rate ÷ 100. Total = amount + GST.

Removing GST: amount before GST = total ÷ (1 + rate ÷ 100). GST = total − that amount.

Figures are rounded to the paisa. On an invoice, GST is worked out on each line, so the total may differ by a paisa or two from a single sum.

This calculator does the arithmetic. It does not decide which rate applies to you. For that, check the rate for your HSN or SAC code, or ask a CA.

Need to bill the client next? The invoice generator does the same split on each line.

Questions

How do I add 18% GST to a price?

Multiply the price by 1.18. On ₹10,000 the GST is ₹1,800 and the total is ₹11,800. Within one state that ₹1,800 is split into ₹900 CGST and ₹900 SGST.

How do I take GST out of a price that already includes it?

Divide the total by 1 plus the rate. At 18%, ₹11,800 ÷ 1.18 = ₹10,000 before tax, so the GST inside it is ₹1,800. Do not just take 18% of ₹11,800 — that gives ₹2,124, which is wrong.

When is it CGST and SGST, and when is it IGST?

If you and your client are in the same state, the tax is split half and half into CGST and SGST. If the client is in another state, the whole amount is IGST. The total tax is the same either way.

What GST rate applies to freelance services?

Most professional services — design, development, writing, consulting, marketing — are at 18%. Check the SAC code for your service, or ask a CA, before you rely on it.

Do I have to charge GST as a freelancer?

Only once you are registered. For services, registration is required when your yearly turnover crosses ₹20 lakh (₹10 lakh in some special category states). Exports and some other cases have their own rules. If you are not registered, you must not charge GST.