GST Calculator
Mode
$
%
Common Rates
GST Amount$10.00
Net (excl. GST)$100.00
Gross (incl. GST)$110.00
The GST Calculator handles both directions of goods and services tax: adding GST onto a tax-exclusive price, or peeling GST back out of a tax-inclusive total. Pick a mode, enter the amount and the GST rate that applies in your country, and the tool reports the net price, the GST portion, and the gross price, each rounded to the nearest cent.
Formula
Add: gst = net × rate; gross = net + gst. Remove: net = gross / (1 + rate); gst = gross − net
- net
- Price excluding GST
- gross
- Price including GST
- rate
- GST rate as a decimal (e.g. 0.10 for 10%)
How it works
- Choose "Add GST" when your figure excludes tax (the net price) or "Remove GST" when your figure already includes tax (the gross price).
- Enter the amount and the GST rate as a percentage, or tap a common-rate chip such as 5%, 10%, 15%, or 18%.
- In add mode the GST is the amount times the rate; in remove mode the net is the gross divided by one plus the rate, and the GST is the difference.
Worked examples
Add 10% GST to a product priced at $100 before tax.
- GST = 100 × 0.10 = $10.00.
- Gross = 100 + 10 = $110.00.
GST $10.00, net $100.00, gross $110.00.
Remove 10% GST from a $110 GST-inclusive invoice.
- Net = 110 ÷ 1.10 = $100.00.
- GST = 110 − 100 = $10.00.
Net $100.00, GST $10.00, gross $110.00.
Frequently asked questions
- What is the difference between GST-inclusive and GST-exclusive pricing?
- A GST-exclusive price is the base amount before tax, to which GST is added. A GST-inclusive price already contains the tax, so removing GST tells you the underlying base amount a business records as revenue.
- What GST rate should I use?
- It depends on your jurisdiction: Australia and many others use 10%, New Zealand 15%, Canada has a 5% federal GST, Singapore 9%, and India applies slab rates such as 5%, 12%, 18%, and 28%. Enter whichever rate applies to your transaction.
- Why is the extracted net not simply the gross minus ten percent?
- Because GST was charged on the smaller net base, not on the gross. You divide by 1.10 rather than subtracting 10% of the gross, otherwise you would understate the net and overstate the tax.
- Is GST the same as VAT or sales tax?
- GST and VAT are essentially the same multi-stage consumption tax under different names. US sales tax differs because it is applied only at the final retail sale rather than at each stage of the supply chain.