GST Calculator
Add GST to a net price or back out GST from a tax-inclusive price in one click.
Mode
GST rate
1,180
Gross totalNet amount
84.7%
GST
15.3%
- 1
GST amount
1,000 × 18% ÷ 100 = 180 - 2
Total (incl. GST)
1,000 + 180 = 1,180
Formula
How this is calculated
The calculator takes three inputs: a Mode (add or remove GST), an Amount of money, and a GST Rate in percent (the common Indian slabs of 5%, 12%, 18% and 28%). The Rate is treated as a percentage, so it is divided by 100 before any arithmetic, and money values carry whatever currency you are working in.
In "add" mode the Amount is the net, pre-tax price. The tax is found by multiplying it by the rate fraction (GST = Amount × Rate ÷ 100), and the gross total is simply Net plus GST. In "remove" mode the Amount is the gross, tax-inclusive price. Because the tax was originally added on top of the net figure, you cannot just subtract the rate; instead the net is recovered by dividing the gross by (1 + Rate ÷ 100), and the GST is the difference between the two.
Results are rounded to two decimal places for display, so a multi-step total may differ by a cent from a hand calculation. The tool assumes a single flat rate on the whole amount and does not handle mixed-rate baskets, cess, or input-tax credits.
About this calculator
Goods and Services Tax (GST) is a value-added tax applied to most goods and services. In "add" mode you start with a net (pre-tax) price and the calculator adds the chosen rate to give the gross, tax-inclusive total. In "remove" mode you start with a gross price that already includes GST and the calculator works backwards to reveal the original net amount and the tax portion.
Removing GST is not the same as simply subtracting the rate. Because the tax was applied on top of the net amount, you must divide the gross by (1 + rate ÷ 100). For example, removing 18% from 1,180 gives a net of 1,000 and GST of 180 — not 1,180 minus 18%.
Frequently asked questions
Divide the tax-inclusive price by 1.18. The result is the net amount; the difference is the GST.
GST was added to the smaller net amount, so subtracting 18% of the larger gross figure overshoots. Dividing by 1.18 reverses it exactly.
The common slab rates of 5%, 12%, 18% and 28% are provided in the dropdown.
Also known as
TG we-Calculate Editorial Team. (2026). GST Calculator [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/gst-calculator
TG we-Calculate Editorial Team. "GST Calculator." TG we-Calculate. 2026. https://we-calculate.com/calculator/gst-calculator.
TG we-Calculate Editorial Team, "GST Calculator," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/gst-calculator
@misc{wecalculate_gst_calculator, title = {GST Calculator}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/gst-calculator}}, year = {2026}, note = {TG we-Calculate} }
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