Sales Tax Calculator
Add sales tax to a pre-tax price or pull the pre-tax price out of a tax-included total, with common Canadian rates built in.
Amount and rate
Calculation
Total with tax
Adding tax vs. removing it
Most invoices show a pre-tax price with sales tax added on top. In many places, especially in Europe, the prices customers see already include tax. Knowing how to pull the pre-tax amount out of a tax-included total matters for revenue reporting, margin math and pricing across borders.
The formulas
- Adding tax: tax = amount × rate, and total = amount + tax
- Removing tax: pre-tax amount = total ÷ (1 + rate), and tax = total minus pre-tax amount
A common mistake is to remove tax by multiplying the total by the rate. That overstates the tax, because the rate applies to the pre-tax amount, not the total.
Frequently asked questions
What rate should I use?
In Quebec, GST plus QST is 14.975%. Ontario HST is 13%. US state rates vary widely, and local taxes can add more. Always confirm the current rate for your jurisdiction before you invoice.
Why is the tax a few cents off from my receipt?
Stores often calculate tax per item and round each line, while this calculator works on the total. Small rounding differences are normal.