Sales Tax Calculator
The rate field starts empty on purpose. This page publishes no rates, because a US rate depends on where the sale is taxed and changes on schedules no single publisher owns.
How do you add sales tax to a price?
Sales tax is a percentage of the net price, added on top of it. The total is the net price plus that tax, which is why the tax is never a percentage of the total.
- Enter the net price — the amount before any tax.
- Enter the rate that applies where the sale is taxed. The field starts empty because this page publishes no rates; the relevant revenue authority is the safe source for it.
- Multiply the price by the rate. What comes out is the tax, and the total is the price plus it.
- To go the other way, switch the widget to take tax out of a total. It divides rather than subtracts, and the table below gives both lines side by side.
The two directions, with your rate as the variable
Which row you want depends on whether the figure in front of you already has the tax in it. The rate is yours in both: write it as a decimal, so 8.25 percent becomes 0.0825.
| What you have | What you want | The line |
|---|---|---|
| A net price | The tax and the total | Tax = net price x rate, and the total is the net price plus that tax. |
| A total with tax in it | The net price and the tax | Net price = total / (1 + rate), and the tax is the total minus that net price. |
Worked Example: $250 at a rate of 8.25 percent
The tax is $20.63 and the total is $270.63. At a rate of 8.25 percent entered by the reader, a $250 net price carries $20.63 of tax and totals $270.63; 8.25 percent is an illustration, not a rate this page claims for any place.
$250.00 at a rate of 8.25 percent → tax $20.63, total $270.63
Now read it backwards, because this is where the money goes missing. Taking 8.25 percent off $270.63 does not return $250.00, and the gap is not a rounding error — it is the difference between a share of the net and a share of the total.
Taking the tax percentage off the total gives the wrong net price, because the percentage was applied to the smaller number: 8.25 percent off a $270.63 total leaves $248.30, but the true net is $250.00.
Which Rate Applies, and Who Decides?
What a rate is made of
A US sales tax rate is usually a state rate plus any county, city and district rates that apply at the point of sale, and those components change on set dates.
Where the rate comes from
This page publishes no tax rate and no lookup by address. You enter the rate that applies where the sale is taxed; only the relevant revenue authority is a safe source for the current figure.
Which sale the rate belongs to
The rate follows the sale, not the seller. Shipping to another state, selling from a stall for a weekend and selling a service rather than goods can all put the sale under a different rate, and the arithmetic on this page does not know which.
Frequently Asked Questions
How do you find the tax inside a total that already includes it?
Divide the total by one plus the rate to get the net price, then take that net price off the total. What is left is the tax. The widget above does it when you switch direction.
Why does subtracting the tax percentage from the total give the wrong net price?
Because the percentage was worked out against the smaller number. The tax is a share of the net price, so taking that share off the larger total removes more than was added.
What sales tax rate should you use?
The one that applies where the sale is taxed. This page publishes none and looks nothing up by address; the revenue authority for that place is the only safe source.
The rest of the site is on the whole tool list.