How to use the GST calculator
Pick "Add GST" to turn a pre-GST price into a GST-inclusive total, or "Remove GST" to find the pre-GST price and GST portion from a total. Enter the amount and your GST rate.
The formulas
Add GST: Total = Price × (1 + rate) · Remove GST: Price = Total ÷ (1 + rate)
Worked example
- Add: $200 at 10% → GST $20, total $220.
- Remove: $220 at 10% → price $220 ÷ 1.10 = $200, of which $20 was GST.
GST rates around the world
GST (Goods and Services Tax) rates differ by country: Australia 10%, New Zealand 15%, Singapore a single rate, India several slabs (commonly 5%, 12%, 18%, 28%), and Canada a federal GST that combines with provincial tax. Always enter the exact rate for your purchase.
Common mistakes to avoid
Subtracting the GST percentage from the total to remove it — divide by (1 + rate) instead. Using the wrong slab in countries with several. Mixing federal and combined rates (as in Canada).
Frequently asked questions
What is 10% GST on $200?
$20, making the total $220.
How do I find the price before GST?
Divide the total by 1 plus the rate as a decimal. $220 ÷ 1.10 = $200.
Which countries use GST?
Australia (10%), New Zealand (15%), India (slabs), Singapore, Canada, and others — at their own rates.
How is GST different from VAT or sales tax?
Same arithmetic; different names and rules by country.
What does GST-inclusive mean?
The price already contains the GST. Use Remove GST to split it out.
Is my data saved?
No. Everything runs in your browser; nothing is uploaded.