What Is a Sales Tax Calculator?
A sales tax calculator quickly figures out how much sales tax you'll pay on a purchase, or — in reverse — how much of a total price is tax versus the item's actual pre-tax price. It's useful for budgeting purchases or checking a receipt.
How to Use the Sales Tax Calculator
- Choose whether you want to add tax to a price, or remove tax from a total you already have.
- Enter the price or total amount.
- Enter your local sales tax rate as a percentage.
- Read your result instantly — no calculate button required.
Sales Tax Formula
Worked Example
Pre-tax price: $100.00
Sales tax rate: 7%
Tax amount: $100 × 0.07 = $7.00
Total price: $107.00
Understanding Your Results
When adding tax, the calculator shows the pre-tax price, the dollar amount of tax, and the final total you'll actually pay. When removing tax from a total (useful for reading a receipt backward), it works the calculation in reverse to isolate the original pre-tax price.
Sales Tax Rates Vary by Location
Sales tax rates differ by country, state or province, and even city or county — some places have no sales tax at all, while others combine state and local rates. Always use your specific local rate for accurate results; check your state or local government's tax authority website if you're unsure.
Common Mistakes to Avoid
- Using a national average tax rate instead of your specific local combined rate.
- Forgetting that some items (like groceries or clothing in some regions) may be tax-exempt or taxed at a different rate.
- Mixing up "add tax" and "remove tax" mode when reverse-engineering a receipt total.
Frequently Asked Questions
Multiply the pre-tax price by the sales tax rate (as a decimal) to get the tax amount, then add that to the price for your total — or just use the calculator above.
Divide the total price by 1 plus the tax rate (as a decimal). For example, a $107 total at 7% tax means the pre-tax price was $107 ÷ 1.07 = $100.
No — many regions exempt certain categories like groceries, prescription medication, or clothing below a certain price, and rates can vary by product category.
Sales tax is typically set by a combination of state, county, and city governments, each of which can set its own rate, so combined rates vary widely even within the same state.
No — sales tax is charged once at the final point of sale, while VAT (value-added tax), used in many countries outside the US, is collected incrementally at each stage of production and distribution.