GST Calculator
Last updated: May 6, 2026Add or remove GST in seconds.
GST Calculator is a free online calculator to add or remove GST in seconds. It runs entirely in your browser, so your files never leave your device — nothing is uploaded. There's no sign-up, no watermark, and it works on any modern browser on desktop or mobile.
How to use GST Calculator
This GST calculator adds GST to a base price or extracts the GST already included in a gross amount, showing the net value, the tax and the total. To add GST it multiplies the net by the rate; to remove it, it divides the gross by (1 + rate) to recover the pre-tax amount. Shop owners, freelancers and accountants use it for quick, accurate invoicing.
Read the full guide: How to Calculate GST: Add or Remove GST From a Price
- 1Enter the amount and select whether it is GST-exclusive or GST-inclusive.
- 2Choose the applicable GST rate, such as 5, 12, 18 or 28 percent.
- 3Read the net amount, the GST portion and the gross total.
Add or remove GST
Handles both forward tax on a base price and reverse tax from an inclusive total.
Clear breakdown
Splits any figure into net, tax and gross so invoices are easy to fill.
Common rates ready
Standard slab rates are built in, so you avoid manual percentage math.
GST Calculator — frequently asked questions
How is GST removed from an inclusive price?
Divide the gross amount by 1 plus the rate as a decimal to get the net price, then subtract the net from the gross to find the GST. For 18 percent, the net is the gross divided by 1.18.
How is GST added to a base price?
Multiply the net amount by the rate to get the tax, then add it to the net for the gross. A net of 1000 at 18 percent adds 180 GST for a 1180 total.
Does it split GST into CGST and SGST?
It shows the total GST amount. For intra-state supplies in India that total is normally divided equally into CGST and SGST, so halving the GST figure gives each component.
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