Free calculator
Reverse sales tax calculator
Enter a price that includes tax and pick the province: you get the price before tax, the GST or HST and any provincial tax inside it.
Where your client is, for services; where the goods are delivered, for goods.
Sales tax
$130.00
- Price before tax
- $1,000.00
- HST 13%
- $130.00
- Total
- $1,130.00
Ontario: HST. Charge provincial tax only if you’re registered for it there.
Make this invoiceHow the tax comes out
Divide the price by one plus the combined rate. $1,130 including Ontario’s 13% HST is $1,000 before tax and $130 HST. Taking 13% off $1,130 gives $146.90, which is wrong.
In Quebec the combined rate is 14.975%: $1,149.75 is $1,000 before tax, GST $50 and QST $99.75. Show GST and QST on separate lines on your invoice — never 14.975% as one rate.
Last updated 2026-10-01. This calculator is a guide, not tax advice.
Frequently asked questions
Why isn’t it just the price × 13%?
Because the tax was worked out on the price before tax, not on the total. Dividing by 1.13 (for 13% HST) gets you back to that price.
Can I quote prices that include tax?
Yes, as long as the invoice says the price includes GST/HST (or shows the tax). Our invoices always show the price before tax and each tax on its own line.
Why is a cent sometimes off?
Each tax is rounded to the cent. When you start from a total, the cent left over by rounding goes to the last tax so everything still adds up to the price you entered.