Sales Tax / GST / VAT Calculator

Multiply the pre-tax price by the tax rate (as a decimal) to get the tax amount, then add it to the price. For example, a $100 price with 8% tax = $100 × 0.08 = $8 tax, for a total of $108. Use the "Add tax" tab above to do this instantly for any rate.

Divide the total by (1 + tax rate as a decimal) to get the pre-tax base price, then subtract that from the total to find the tax amount. For example, a $108 total that includes 8% tax has a base price of $108 ÷ 1.08 = $100, meaning $8 was tax. Use the "Extract tax" tab for this.

They're calculated the same way mathematically, but differ by country and system. US sales tax is typically added at the point of sale and varies by state/city. GST (Goods and Services Tax, used in countries like Australia, Canada, India) and VAT (Value Added Tax, used across the EU and UK) are usually included at each stage of production but shown to consumers as a single rate on the final price.

This is common in VAT/GST countries where displayed prices already include tax, and you need to know the pre-tax base price for accounting, expense reports, or invoicing purposes — for example, to reclaim VAT on a business expense.

No — tax rates vary by country, state, and even city or product category, so you enter the rate yourself. The quick-preset buttons (5%, 10%, 15%, 20%) are common reference points, but always confirm the exact rate that applies to your situation.