Transparent method
The formula
Worked example
Example inputs
How to interpret the result
Sales tax applies to the pre-tax price, and confusing that with the final price leads to a mismatched calculation in either direction: computing tax on top of a number that already includes tax overcharges the buyer, while backing tax out of a final price with the wrong formula understates what was actually collected.
Before you rely on it
What to check
Confirm whether your starting figure is the pre-tax price or the final price including tax before running the calculation: the two need different formulas, not the same one run twice.
The common error
Where people go wrong with sales tax calculator
Adding the tax rate to a price that already includes tax. Reversing a final price back to its pre-tax base requires dividing by one plus the rate, not simply subtracting the rate as a percentage of the total.
Sensitivity evidence
How combined sales-tax rate changes the total price after tax
| Combined sales-tax rate | Total price after tax | Sales tax |
|---|---|---|
| 5.5% | $264 | $14 |
| 6.5% | $266 | $16 |
| 7.5%worked example | $269 | $19 |
| 8.5% | $271 | $21 |
| 9.5% | $274 | $24 |
Every input, tested
Which input moves the total price after tax most
| Input | Tested from | To | Total price after tax at each end | Swing |
|---|---|---|---|---|
| Pre-tax price | $225 | $275 | $242 to $296 | $54 (20%) |
| Combined sales-tax rate | 6.5% | 8.5% | $266 to $271 | $5.00 (1.9%) |
Two variables at once
Total price after tax by combined sales-tax rate and pre-tax price
| Combined sales-tax rate \ Pre-tax price | $200 | $250 | $300 |
|---|---|---|---|
| 5.5% | $211 | $264 | $317 |
| 6.5% | $213 | $266 | $320 |
| 7.5% | $215 | $269 | $323 |
| 8.5% | $217 | $271 | $326 |
| 9.5% | $219 | $274 | $329 |
Step by step
The worked example, input by input
| Input | Value used |
|---|---|
| Pre-tax price | $250 |
| Combined sales-tax rate | 7.5% |
| Total price after tax | $269 |
| Sales tax | $19 |
Where the inputs come from
Pre-tax price is the listed price before tax. The combined sales tax rate adds the state rate and any county, city and special district rates that apply where the sale is made or delivered; state revenue departments and local tax lookup tools publish the combined rate for an address. Rates differ within the same state, so use the rate for the exact location. Some items, such as groceries or clothing, are taxed at a lower rate or exempt in some states.
When the result stops applying
Taxability depends on the item and the state: services, digital goods and food are treated differently. Some places have tax holidays. Sales tax on vehicles may be based on where you register the car. Businesses that collect tax must also register and remit it. Prices that include tax need to be reversed to find the pre-tax amount.
What to compare it with
For comparing the true cost of large purchases see the auto loan and mortgage calculators, and the property tax page for the other local tax. The percentage and discount calculators help work backward from a tax-inclusive price. Keep receipts if you can deduct sales tax on your return.
People also ask
Frequently asked questions
How do I find the sales tax rate for my address?
Check your state department of revenue's rate lookup, which lists combined state and local rates by address. Rates can differ block to block near jurisdiction lines.
Do I pay sales tax on online purchases?
In most states yes, since sellers are required to collect tax based on the delivery address after the 2018 Wayfair decision. If not collected, you may owe use tax.
How do I calculate the pre-tax price from a total?
Divide the total by one plus the tax rate. A $268.75 total at 7.5% comes from $250 before tax.