The formulas
Tax = price × rate ÷ 100 · Total = price × (1 + rate ÷ 100)
Price before tax = total ÷ (1 + rate ÷ 100)
Rate = (after − before) ÷ before × 100
Price before tax = total ÷ (1 + rate ÷ 100)
Rate = (after − before) ÷ before × 100
Worked examples
- Adding tax: $100 at 7.25% is 100 × 0.0725 = $7.25 tax, for a total of $107.25.
- Removing tax: a $107.25 receipt at 7.25% was 107.25 ÷ 1.0725 = $100 before tax. Taking 7.25% off $107.25 would give $99.47, which is wrong, because the tax was figured on the smaller price.
- Finding the rate: $50 rang up as $53.50, so the tax was $3.50 and the rate is 3.50 ÷ 50 = 7%.
Find your rate
Sales tax in the US is set by states, and many counties and cities add their own, so the rate can change from one town to the next. Rates also change over time, so this calculator doesn't assume one. Check your state's department of revenue, or the rate printed on a recent receipt from the same store. Five states (Alaska, Delaware, Montana, New Hampshire and Oregon) have no statewide sales tax, although some Alaska towns charge a local one.
Limitations
- Stores round tax to the cent, sometimes per item and sometimes on the whole receipt, so results can differ by a penny.
- Many states tax groceries, clothing or medicine at a lower rate or not at all. A receipt mixing taxed and untaxed items won't give a single clean rate.
- Outside the US, VAT or GST is usually already included in the shelf price. Use "Remove tax" to see the price without it.