01 Direction

Add GST Amount is before tax Remove GST Amount already includes tax

Amount before GST Your taxable value. The tax is added on top.

02 Rate

Compensation cess In percent, on the same taxable value. Leave at 0 unless your goods attract cess.

03 Place of supply

Same state CGST + SGST Other state IGST

Reverse charge applies Adds the declaration your invoice needs when the buyer pays the tax.

Nothing leaves this device. The arithmetic runs in this browser tab. No amounts are sent anywhere, and the page works offline.

GST, both directions.

Put tax on top of your price, or pull it back out of a price that already has it in. The second one is where the mistakes happen.

Type an amount to see the breakdown.

Pick a direction on the left first. "Remove GST" is the one to use on a marketplace settlement figure or an MRP - taking 18% of an inclusive amount overstates the tax.