Sales Tax Calculator
Add sales tax to any price
Add sales tax to a price, or work backwards from a receipt total to find the pre-tax amount. This sales tax calculator does both, and the reverse direction is the one worth having: backing tax out of a total is a division, not a subtraction, and taking the rate off the total gives the wrong answer every time.
Adding tax to a price
The forward direction is straightforward: tax = price × rate, and the total is the two added. A $100 purchase at 7.25% is $7.25 of tax and $107.25 to pay — the price plus tax figure you hand over at the till.
| Tax rate | Tax on $100 | Total to pay | Pre-tax price inside a $100 total |
|---|---|---|---|
| 4% | $4.00 | $104.00 | $96.15 |
| 6% | $6.00 | $106.00 | $94.34 |
| 7.25% | $7.25 | $107.25 | $93.24 |
| 8.25% | $8.25 | $108.25 | $92.38 |
| 9.5% | $9.50 | $109.50 | $91.32 |
| 10.25% | $10.25 | $110.25 | $90.70 |
The last column is the reverse calculation — what a $100 tax-inclusive total was before tax.
Notice that the two middle columns are not mirror images. Tax of $7.25 on $100 gives a $107.25 total, but a $100 total does not contain $7.25 of tax — it contains $6.76. That asymmetry is the whole subject of the next section.
Backing tax out of a total is a division
To find the pre-tax amount inside a tax-inclusive total, divide: pre-tax = total ÷ (1 + rate). A $107.25 total at 7.25% came from exactly $100.00.
The tempting shortcut — subtracting 7.25% from the total — gives $99.47. It is wrong, and it is always wrong in the same direction: too low. The reason is that the tax was calculated on the smaller pre-tax figure, so taking the same percentage off the larger total removes too much.
| Tax rate | Correct pre-tax price | Subtracting the rate instead | Error |
|---|---|---|---|
| 4% | $96.15 | $96.00 | $0.15 |
| 6% | $94.34 | $94.00 | $0.34 |
| 7.25% | $93.24 | $92.75 | $0.49 |
| 8.25% | $92.38 | $91.75 | $0.63 |
| 9.5% | $91.32 | $90.50 | $0.82 |
| 10.25% | $90.70 | $89.75 | $0.95 |
On a $100 tax-inclusive total. The error grows with the rate — and scales with the amount.
Under a dollar on a $100 receipt sounds harmless. On a $12,000 tax-inclusive invoice at 9.5% the same mistake is $98.90, and anyone separating tax across a year of expenses repeats it on every line. Switch the calculator to "back tax out of a total" and it does the division, showing the shortcut's answer alongside so the gap is visible.
Who needs the reverse calculation
- Expense claims and bookkeeping. Receipts show a total; the ledger needs the net amount and the tax separately.
- Tax-inclusive pricing. Anywhere prices are displayed with tax already in them, which is standard for VAT and GST countries and common for US restaurant and vending prices.
- Checking a receipt. The fastest way to confirm the till applied the rate you expected.
- Setting a tax-inclusive price. To land on a round $50 including 8.25% tax, the shelf price is $46.19 — a division, again.
Why the rate is not one number
US sales tax is layered: a state rate, plus county, city and special district rates that stack on top. The combined figure depends on the delivery address, not the store's address, which is why online orders to two neighbouring towns can carry different totals. Rates change on legislative schedules, and there is no single national rate to look up.
Five states levy no statewide sales tax at all, and several states exempt or reduce tax on groceries, prescription medicines and clothing. That means the rate that applies to your basket may differ from the rate that applies to your address. This calculator takes whatever rate you supply and does the arithmetic; finding the right rate for a specific address and product category is a job for your state's revenue department.
Sales tax, VAT and GST
The arithmetic on this page works for all of them, but they are not the same tax. US sales tax is charged once, at the final retail sale, and businesses buying for resale are exempt. VAT and GST are charged at every stage of the chain with businesses reclaiming what they paid, so the consumer bears an equivalent amount by a different route.
The practical difference for anyone using a calculator is display convention: US prices are almost always quoted before tax, while VAT and GST countries quote tax-inclusive prices. That is precisely why the reverse direction matters more outside the US — and why so many tools get it wrong by subtracting.
An arithmetic tool, not tax advice. Rates and exemptions vary by jurisdiction and product — check your state or national revenue authority.
How this sales tax calculator works out its numbers
Adding tax: tax = price × rate ÷ 100 and the total is price + tax. Removing tax: pre-tax = total ÷ (1 + rate ÷ 100), with the tax being the remainder.
- Removing tax is a division, not a subtraction. Taking the rate off the total understates the pre-tax price every time, by $0.49 on a $100 total at 7.25% and by more as the rate rises. The calculator shows the incorrect shortcut alongside the right answer rather than only asserting the difference.
- No rate table is built in. US sales tax combines state, county, city and district rates and depends on the delivery address, with exemptions for categories such as groceries and medicines in many states. Any embedded table would be wrong somewhere and stale everywhere, so the rate is yours to supply.
- Results are rounded to the cent. Some jurisdictions specify their own rounding for tax lines, so a till receipt can differ by a cent.
- Discounts come first. Sales tax is charged on the amount actually paid, so apply any discount before the tax — the discount calculator does this directly.
Reviewed September 2026.
Figures reviewed . Every worked example on this page is checked against the calculator above.
Sales Tax Calculator: frequently asked questions
How do I calculate sales tax?
Multiply the price by the rate as a decimal. At 7.25%, a $100 purchase carries $7.25 of tax for a $107.25 total. Enter the price and rate and the calculator shows the tax and the total separately.
How do I work out the price before tax from a total?
Divide the total by (1 + rate). A $107.25 total at 7.25% came from exactly $100.00. Do not subtract the rate from the total — that gives $99.47, which is wrong.
Why can't I just subtract the tax rate from the total?
Because the tax was calculated on the smaller pre-tax amount, so taking the same percentage off the larger total removes too much. On a $100 total at 7.25% the shortcut is $0.49 out, and the error grows with both the rate and the amount.
How much sales tax is included in a $100 receipt?
It depends on the rate. At 7.25% the pre-tax price is $93.24 and the tax inside is $6.76 — not $7.25, which is what the same rate would add to a $100 pre-tax price.
What is the sales tax rate where I live?
There is no single answer — US rates combine state, county, city and special district levies, and depend on the delivery address rather than the store's. Check your state revenue department for the exact combined rate.
Is sales tax charged before or after a discount?
After. Tax applies to what you actually pay, so the discount comes off first. An $80 item at 30% off with 7.25% tax is $56.00 plus $4.06 of tax.
How do I set a price that includes tax?
Divide the target total by (1 + rate). To land on exactly $50 including 8.25% tax, the shelf price is $46.19.
Does this work for VAT and GST?
The arithmetic is identical, though the taxes differ — sales tax is charged once at retail while VAT and GST are collected at each stage with businesses reclaiming. Since VAT and GST countries usually display tax-inclusive prices, the reverse direction is the one you will use.