Sales Tax Calculator
Add sales tax to a price, or back it out of a tax-included total.
How it works
Total = price × (1 + rate) · Price before tax = total ÷ (1 + rate)
Adding tax is a simple multiply. Backing tax out of a receipt total requires dividing by (1 + rate) — subtracting the percentage from the total is a common mistake that gives the wrong answer.
Worked example
At 7.25%: a $100 item totals $107.25. Backing tax out of a $107.25 receipt: 107.25 ÷ 1.0725 = $100.00 pre-tax.
Frequently asked questions
What is the highest US sales tax?
Combined state + local rates top out above 10% in parts of Louisiana, Alabama and Washington. Five states charge no state sales tax at all.
Why can’t I just subtract 7.25% from the total?
Because the tax was computed on the smaller pre-tax price, not the total. Subtracting the rate from the total over-removes tax.
Does this work for VAT/GST?
Yes — the math for VAT and GST is identical; only the names and rates differ.
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This calculator is for educational purposes. Double-check important results before acting on them.