How to Calculate GST with Examples

To add GST: GST = Price × Rate ÷ 100 and Total = Price + GST. To remove GST from a GST-inclusive price: GST = Total × Rate ÷ (100 + Rate).

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Add GST to a price (exclusive)

If a price is 1,000 and the rate is 18%, GST = 1,000 × 18 ÷ 100 = 180 and the total is 1,180.

Remove GST from a total (inclusive)

If a total of 1,180 includes 18% GST, GST = 1,180 × 18 ÷ 118 = 180 and the base price is 1,000.

CGST, SGST and IGST

For sales within one state, GST is split equally into CGST and SGST (9% + 9% for an 18% rate). For sales between states, IGST applies at the full rate.

Check the current rate

GST rates and slabs are revised by the GST Council from time to time. Confirm the rate for your product or service on the official schedule before invoicing. This is general information, not tax advice.

Frequently asked questions

Multiply the price by 0.18 to get GST, then add it to the price.

CGST and SGST apply within a state; IGST applies between states.

Registered businesses can often claim credit on eligible purchases; confirm the rules.

General information, not tax, legal or accounting advice. Rules and rates change; confirm with a qualified professional. Only document real transactions.