Sales Tax Calculator
Tax = price x rate / 100. Total = price + tax. To remove tax from a total, price before tax = total / (1 + rate / 100).
Add tax to a price or pull it out of a total
Pick a direction first. Adding tax answers the checkout question: what will this 100 dollar item actually cost at the register? Removing tax answers the bookkeeping question: how much of a 108.25 receipt was the item, and how much went to tax?
Then enter your rate. The calculator cannot know it, because sales tax in the United States is set by states, counties and sometimes individual cities. A recent receipt from the same store is the fastest place to read your combined rate.
What the two numbers tell you
The result always splits the total into the price and the tax, whichever direction you calculated. That split is the useful part. The total tells you what you paid, but the split tells you what the item cost and what was collected on top.
For expense reports and resale paperwork, the pre-tax figure is usually the one you need. For budgeting at the shelf, the with-tax figure is the honest price of the item.
The forward and reverse formulas
Adding tax is one multiplication: tax equals price times the rate divided by 100. A 100 item at 8.25 percent carries 8.25 in tax, so the register shows 108.25.
Going backwards is a division, not a subtraction. Price before tax equals the total divided by 1 plus the rate as a decimal. 108.25 divided by 1.0825 returns the original 100.
Checking a real receipt
Say a receipt shows 53.49 and your area charges 7 percent. Divide 53.49 by 1.07 and you get 49.99, the shelf price. The remaining 3.50 is the tax.
If the division lands on an odd shelf price like 49.83, either the rate you used is wrong or some items on the receipt were taxed at a different rate. Groceries, clothing and medicine get special treatment in many states.
Why subtracting the percent gives the wrong price
It feels natural to take 8.25 percent off 108.25 to undo the tax, but that takes the percentage of the larger after-tax number. You get 99.32, not 100.
The tax was charged on the smaller pre-tax price, so the only clean way back is dividing by 1.0825. The gap grows with the rate, which is why quick receipt math in high-tax cities always looks slightly off.
What this calculator does not decide
The math works for any flat percentage. What it cannot do is tell you the rate, whether an item is exempt or how your state rounds. Those rules live with state and local tax authorities, and stores program them into the register.
If a register total disagrees with your check by a cent or two, line-item rounding at the store is the usual reason, not a math error on either side.
Sales Tax Calculator FAQ
How do I calculate sales tax on a purchase?
Multiply the price by your rate and divide by 100. A 60 dollar item at a 6 percent rate carries 3.60 in tax, for a total of 63.60.
If your area stacks a state rate and a city rate, add them together first and apply the combined rate once.
How do I figure out the price before tax?
Divide the total by 1 plus the rate as a decimal. At 8 percent, divide by 1.08. At 8.25 percent, divide by 1.0825.
This reverses the original multiplication, which is why subtracting the percentage never lands exactly on the original price.
Why is my receipt tax slightly different from this calculator?
Registers round each taxed line to the nearest cent, and some items may be taxed at a reduced or zero rate. Over a long receipt those cents add up to a small visible gap.
The percentage math is still right. The difference comes from rounding rules and item categories, not the formula.
What sales tax rate should I enter?
The combined rate where the purchase happens: state plus county plus city where each applies. A recent receipt from the same store shows it directly.
State revenue departments publish official rate tables if you want to verify.
Do all US states charge sales tax?
No. Alaska, Delaware, Montana, New Hampshire and Oregon have no statewide sales tax.
Alaska still allows local rates, so a city there can charge tax even though the state does not.
Is this tax advice?
No. The calculator applies the percentage you enter. Exemptions, tax holidays, item categories and filing questions belong to your state or local tax authority, or to a professional who knows your situation.