Add sales tax to a price, or work backwards from a tax-inclusive total
Enter a valid price
Enter a valid rate (0-30)
Enter a quantity (1-999)
Sales tax is charged on the final retail price of most goods, and it is added at the register rather than baked into the sticker price. That means the number you see on a shelf is rarely the number you pay — which is exactly the gap this calculator closes.
Enter a price and a sales tax rate, then tell it whether that price already includes tax. It returns the pre-tax amount, the tax itself and the tax-inclusive total. A quantity field multiplies everything for you, so a cart of twelve identical items is handled in one step.
The third line is the one people get wrong. Removing tax is not "subtract the same percentage" — that under-states the pre-tax amount, because the tax was charged on the smaller number, not the bigger one.
A $100 item at an 8.25% combined rate: tax = 100 × 8.25 ÷ 100 = $8.25, so the total is $108.25. Now reverse it. Given a receipt showing $108.25, dividing by 1.0825 gives $100.00 — the correct pre-tax figure. Subtracting 8.25% from $108.25 would give $99.31, which is wrong by 69 cents.
| Pre-tax | Rate | Tax | Total |
|---|---|---|---|
| $100.00 | 8.25% | $8.25 | $108.25 |
| $249.99 | 7.00% | $17.50 | $267.49 |
| $1,000.00 | 10.25% | $102.50 | $1,102.50 |
For a business pricing a product, run the calculation backwards: decide the total you want a customer to see, then strip the tax out to find the revenue that is actually yours.
销售税在零售环节按最终售价计征，通常在结账时才加上，而不是标在价签里。也就是说货架上看到的数字，几乎都不是你实际要付的数字 —— 这个计算器补的就是这道缝隙。
输入价格与销售税率，并选择该价格是否已经含税。它会给出税前金额、税额与含税总价。数量字段会自动帮你乘算，所以购买十二件同款商品只需一步就能算完。
第三行是最容易做错的一步。剥离税额不是「减去同一个百分比」—— 那样会把税前金额算小，因为税本身是按那个较小的金额征收的，而不是按较大的金额。
一件 100 元的商品，合并税率 8.25%：税额 = 100 × 8.25 ÷ 100 = 8.25 元，含税总价 108.25 元。反过来算一遍：小票上显示 108.25 元，除以 1.0825 得到 100.00 元 —— 这才是正确的税前金额。若直接用 108.25 减去 8.25%，会得到 99.31 元，误差 0.69 元。
| 税前金额 | 税率 | 税额 | 含税总价 |
|---|---|---|---|
| 100.00 元 | 8.25% | 8.25 元 | 108.25 元 |
| 249.99 元 | 7.00% | 17.50 元 | 267.49 元 |
| 1,000.00 元 | 10.25% | 102.50 元 | 1,102.50 元 |
如果你是商家在为商品定价，可以反着算：先定好你希望顾客看到的含税总价，再把税剥出来，剩下的才是真正属于你的收入。
Multiply the pre-tax price by the tax rate: tax = price × rate ÷ 100. Add that to the price for the total. A $100 item at 8.25% carries $8.25 of tax and costs $108.25.
Divide the tax-inclusive total by 1 + (rate ÷ 100). A $108.25 total at 8.25% comes back to 108.25 ÷ 1.0825 = $100.00 before tax, so the tax paid was $8.25.
Use the combined rate for the delivery address — state plus county plus city plus any special district. In the US that combined figure is what appears on the receipt, and it changes by ZIP code.
Last reviewed: October 5, 2026 · How we calculate · Sources: IRS, state departments of revenue, Streamlined Sales Tax
最近复核：2026 年 10 月 5 日 · 我们的计算方法 · 来源：IRS、各州税务局、简化销售税委员会