Sales Tax & GST Calculator

Add or remove sales tax, VAT and GST with provincial and regional presets, then build an itemised mini-invoice.

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Updated: October 2026

Need to know how much tax goes on top of a price, or what a total includes? The Sales Tax & GST Calculator works out the tax amount and the final figure so shoppers, small sellers, and freelancers can check a bill before they pay or send an invoice.

Working out sales tax or GST on a price

Enter the price you want to check in the amount field. Use the price before tax if you are adding tax, or the total if you already have it.
Enter the tax rate that applies where you buy or sell. Use the percentage shown on your receipt or from your local tax authority.
Choose the option that matches your situation, such as adding tax to a base price or removing tax from a total, if the calculator offers that choice.
Run the calculation and note the tax amount and the final total.
Compare the result with your receipt or invoice before you rely on it.

What the numbers mean

The tax amount is the extra money charged on the price. The total is the price plus that tax. If you start with a total that already includes tax, the base price is lower than the total, and the tax is the difference between the two.

Results use the same currency as the amount you entered. Check that you are reading the right line, because the tax amount and the total are often close in size and easy to mix up.

Mistakes that change the total

Entering a tax-inclusive total as if it were a base price. This adds tax twice.
Using a rate from a different region. Sales tax in some places is set by state, province, or city, so a national rate may not apply.
Typing the rate as a whole number when the tool expects a percentage, or the other way around.
Rounding too early. Keep full decimals during the calculation and round only the final figure.

Where the estimate may differ from your bill

This calculator applies the single rate you enter. It does not know which items are exempt, which goods use a reduced rate, or whether a local surcharge applies. Shipping, discounts, and fees may be taxed differently by a seller. Rounding rules on receipts can also make the final amount a few cents different.

For tax filing or legal records, confirm the rate and rules with your tax authority or accountant.

Answers to common questions about sales tax and GST

What is the difference between sales tax and GST?

Sales tax is usually charged at the point of sale in a single layer set by a state, province, or city. GST is a goods and services tax applied across a country, though some places use different names and structures. Use the rate that matches where the sale takes place.

Should I enter the price before or after tax?

Enter the price before tax if you want to add tax. Enter the total if you want to find the amount of tax already included.

Why does my receipt show a slightly different total?

Receipts can round tax per item or per order, and some items may be exempt or taxed at a different rate. The calculator gives an estimate based on the rate you enter.

Can I use this calculator for invoices?

You can use it to check amounts before you issue an invoice. Confirm the correct rate and tax rules for your business and location before you rely on the figures.