Sales tax calculator
Add tax to a price, or find the tax already inside a total.
- Add tax or extract it
- Any tax rate
- Updates as you type
How to calculate sales tax
- Pick add tax or extract tax.
- Type the amount and the tax rate.
- Read the tax amount and the other total.
Adding tax and taking it back out
- Add tax: tax = amount x rate / 100, and total = amount x (1 + rate / 100). $250 at 8% is $20 of tax and a $270 total.
- Extract tax: pre-tax amount = total / (1 + rate / 100), and tax = total minus the pre-tax amount. A $216 total at 8% is $200 before tax plus $16 of tax.
Tax on $80 at common rates
| Rate | Tax added to $80 | Total | Tax inside an $80 total |
|---|---|---|---|
| 4% | $3.20 | $83.20 | $3.08 |
| 6% | $4.80 | $84.80 | $4.53 |
| 7% | $5.60 | $85.60 | $5.23 |
| 8% | $6.40 | $86.40 | $5.93 |
| 10% | $8.00 | $88.00 | $7.27 |
The last column is always smaller than the second. Tax added on top is a percentage of the price, while tax inside a total is a percentage of a smaller pre-tax amount.
Why there is no single US sales tax rate
The US has no national sales tax. Each state sets its own rate, and many counties and cities add a local rate on top, so the combined rate can change from one town to the next. Alaska, Delaware, Montana, New Hampshire and Oregon have no statewide sales tax, though some Alaska towns charge a local one. Some states also tax groceries or clothing at a different rate, or not at all.
Many other countries use a value added tax (VAT) or a goods and services tax (GST) that is already included in the price on the shelf. For those receipts, extract mode shows how much of the price is tax.
Where tax math usually goes wrong
- Multiplying a receipt total by the tax rate to find the tax. A $216 total at 8% holds $16 of tax, not $17.28.
- Using a state rate alone when a county or city rate also applies, which understates the tax.
- Rounding the tax on each item separately and then comparing it to a receipt that rounds once on the subtotal. The two can differ by a cent or two.
Sales tax calculator FAQ
How much is 7% tax on $100?
7% tax on $100 is $7, for a total of $107.
How do I find the tax already included in a total?
Use extract mode. A $107 total with 7% tax means the pre-tax amount was $100 and the tax portion was $7.
Why can't I just multiply the total by the tax rate?
Multiplying the total by the rate overstates the tax, since the rate applies to the pre-tax amount, not the total. Extract mode divides by 1 plus the rate instead.
Do sales tax rates vary by location?
Yes, in the US they vary by state, county and city. Check your local rate before assuming a percentage.
What is 8% tax on $250?
8% tax on $250 is $20, for a total of $270.
A receipt shows $216 total with 8% tax included. What was the price before tax?
$200. Divide the total by 1.08 to remove the tax, which leaves a $16 tax portion.
Does this calculator know my local tax rate?
No. You enter the rate yourself, since sales tax depends on your state, county, city and sometimes the type of item being sold.
How do I find the tax rate if I only know the total and the tax amount?
Subtract the tax from the total to get the pre-tax amount, then divide the tax by that pre-tax amount and multiply by 100. A $216 total with $16 of tax has a $200 pre-tax amount, so the rate is 16 / 200 x 100, or 8%.