売上税計算機
税抜価格に税を加算、または税込み総額から税を抜く双方向計算
Calculation Mode
使用例
Results
計算方法
Sales Tax
もし…だったら？
各行は現在の入力値で再計算されます。行をタップすると適用されます。
2つのプランを比較
Enter price and tax rate
Fill in the price and your sales tax rate above
Sales Tax Calculator FAQ
How do I calculate sales tax from a total?
Divide the tax-inclusive total by (1 + rate). For example, at 8% tax, $108 total comes from $108 ÷ 1.08 = $100 net price, so the tax included is $8. Switch the calculator to "Remove tax from a total" mode to do this automatically.
How is sales tax added to a price?
Multiply the net price by the tax rate to get the tax amount, then add it: at 8% tax, a $100 item costs $100 × 0.08 = $8 tax, for a $108 total.
What rate should I enter?
Enter the combined rate for your location. In the US, state, county, and city rates stack — for example a 6% state plus a 2% county rate means entering 8%. Check your receipt or your state revenue agency for the exact combined rate.
Why doesn't the reverse calculation just multiply by the rate?
Because the tax was computed on the original net price, not on the tax-inclusive total. Multiplying $108 by 8% gives $8.64, which is wrong. Dividing by 1.08 recovers the true net price of $100 and the true tax of $8.