Sales Tax Calculator

What this calculator answers

Three questions about the same receipt: how much tax a price carries and what the total comes to; how much of a tax-included total is tax, and what the price was before it; and what rate a receipt used. Every answer is rounded to the cent, half a cent up, and the steps show the unrounded figure so you can see where a cent went. You enter the rate, because rates depend on the exact address and change over time.

How to use it

• Calculation: Add tax starts from the price. Remove tax (reverse sales tax) starts from a tax-included total. Find rate starts from both.
• Price before tax: the price or the receipt subtotal, in dollars and cents. 249.99, $249.99 and 1.2k all work.
• List items separately (Add tax only): one price per item, with Tax-free ticked for items your state doesn’t tax. The list keeps a running subtotal, and Paste rows takes rows copied from a spreadsheet: a price, then yes or no for tax-free.
• Total with tax: the amount paid, tax included.
• Sales tax rate: the combined rate in percent. Type 7.75 for 7.75%, not 0.0775. Tick Enter state and local rates separately to type up to four rates (state, county, city, special district); they are added, and a blank one counts as none.

Results update as you type. Each Try button loads a receipt worked through below: the four rate parts, the three items with one tax-free, the $18.00 total that no price fits, and the $86.40 subtotal with its $92.66 total. To compare two rates or two stores, press Save for comparison, change an input and save again: each saved result shows its difference from the first.

How to calculate sales tax

Multiply the price by the rate as a decimal, round to the nearest cent, and add the tax to the price.

$$\text{tax} = \operatorname{round}(P \times r) \qquad \text{total} = P + \text{tax}$$

• $P$ is the price before tax, in dollars.
• $r$ is the combined rate as a decimal: 7.75% is 0.0775.
• $\operatorname{round}$ goes to the nearest cent. The third decimal decides: 5 or more rounds up, 4 or less rounds down. Ohio’s law and California’s regulation both round this way.

Worked example: $249.99 at 7.75%

1. Rate as a decimal: 7.75 ÷ 100 = 0.0775.
2. Tax before rounding: $249.99 × 0.0775 = $19.374225.
3. The third decimal is 4, so the tax rounds down to $19.37.
4. Total: $249.99 + $19.37 = $269.36.

The table under the result repeats the rate on round prices: at 7.75%, $10.00 carries $0.78 of tax, $100.00 carries $7.75 and $1,000.00 carries $77.50. When the product lands exactly on half a cent, it rounds up: $27.00 at 6.5% is exactly $1.755, so the tax is $1.76.

Reverse sales tax: find the price before tax from the total

Divide the total by 1 plus the rate and round to the cent; the tax is what’s left of the total.

$$P = \frac{\text{total}}{1 + r} \qquad \text{tax} = \text{total} - P$$

For a $269.36 total at 7.75%: $269.36 ÷ 1.0775 = $249.986079…, which rounds to $249.99, so the tax is $269.36 − $249.99 = $19.37. The calculator then checks the answer the way a seller would, adding tax to $249.99: that gives back $269.36.

Don’t take 7.75% of the total instead. The tax was charged on the smaller pre-tax price, so $269.36 × 0.0775 = $20.8754, or $20.88, overstates it, and the “price” it leaves, $248.48, is $1.51 too low. At 7.75%, tax is 7.75 ÷ 107.75 = 7.1926% of a tax-included total.

When no whole-cent price gives the total

Each extra cent of price adds 1.0775 cents to the total, so the totals jump a cent now and then. Of the 10,000 totals from $10.00 to $109.99, 719 can’t come from any whole-cent price at 7.75%, about 1 in 14.

$18.00 is one of them. The exact price is $18.00 ÷ 1.0775 = $16.705336…, but $16.70 plus its tax ($1.29) is $17.99 and $16.71 plus its tax ($1.30) is $18.01. The calculator shows the nearest cent, $16.71, with $1.29 as the rest of the total, and says that no price fits exactly. A receipt like that points to a slightly different rate, tax rounded item by item, or a tax-free item on the same bill.

How to find the sales tax rate from a receipt

Subtract the subtotal from the total to get the tax, then divide the tax by the subtotal.

For a $86.40 subtotal and a $92.66 total, the tax is $6.26 and $6.26 ÷ $86.40 = 0.0724537…, or 7.2454%. That odd figure comes from rounding: before it was rounded, the tax could have been anything from $6.255 up to $6.265, so any rate from 7.2396% to 7.2511% gives $6.26, including 7.25%. The width of the range is one cent divided by the subtotal, so a bigger receipt pins the rate down better: on a $1,000.00 subtotal with $72.50 of tax it runs from 7.2495% up to (not including) 7.2505%.

The subtotal must hold only taxed items. If the receipt with three items below, $32.27 before tax and $34.24 after, is read as one purchase, the rate comes out as 6.1047% instead of 7.75%, because $6.79 of the subtotal was never taxed.

Combining state, county and city rates

Add them. The combined rate is the state rate plus every local rate that applies where the sale takes place, and the tax is the price times that sum.

A 5% state rate, 1.75% county, 0.75% city and 0.25% special district add up to 7.75%, so $249.99 carries the same $19.37. The Tax by rate part table splits it: $12.4995, $4.374825, $1.874925 and $0.624975 before rounding. Rounded one part at a time they come to $12.50 + $4.37 + $1.87 + $0.62 = $19.36, a cent less than rounding the combined tax once.

Why your receipt may differ by a cent

Three ways of rounding can give different answers from the same numbers, all at 7.75%:

Ohio’s law lets a seller figure tax per item or per invoice, so both of the first two can appear on real receipts. The calculator charges the tax once on the taxed subtotal (the headline) and shows the item-by-item figure beside it. With the $1.97 figure, the three items above cost $34.24 in total.

Is sales tax charged before or after a discount?

It depends on who pays for the discount, and the rule comes from your state. In Washington, for example, a store’s own discount or coupon lowers the price that is taxed, while a coupon that a third party pays the store back for stays in the taxed price.

When a discount lowers the taxed price, enter the discounted price. A $40.00 store coupon on the $249.99 item at 7.75% leaves $209.99 × 0.0775 = $16.274225, or $16.27 of tax, for a total of $226.26. If the same $40.00 came off as a coupon that a third party reimburses, the tax would stay $19.37 on the full $249.99, and you would pay $249.99 − $40.00 + $19.37 = $229.36.

Tax-included prices and VAT

Remove tax works for any price that already includes a tax at one rate, VAT included. HMRC calls the share of tax in such a price the VAT fraction, rate ÷ (100 + rate): at 20% it is one-sixth, so a 2.40 VAT-inclusive price is 2.00 plus 0.40 of VAT. The Sales tax tile shows that share for your rate, and the Price before tax for other totals table does the split for round tax-included prices a seller might post: at 7.75%, $20.00 is $18.56 plus $1.44 of tax.

In California, for example, a price is presumed to include sales tax when the seller posts a notice saying so. VAT has its own invoicing and rounding rules; this calculator does only the arithmetic.

Where to find your sales tax rate

Look up the full address of the sale on your state tax agency’s website. New York’s Jurisdiction/Rate Lookup and Washington’s Tax Rate Lookup Tool are two examples; both give the combined state and local rate for an address. Local rates change, which is why this calculator asks for the rate rather than storing a table.

Reading the result

• Add tax: the headline is the tax, with the total beside it. Tax before rounding shows the unrounded product and which way it rounded. With items listed, Tax by item shows each item’s tax on its own and the item-by-item total.
• Remove tax: the headline is the price before tax. A note either confirms that the price plus its tax gives back your total or names the two nearest prices when none does. Exact price before tax is the unrounded quotient.
• Find rate: the headline is tax ÷ price. Rates that give this tax is the range the rounded tax allows.
• Tax by rate part appears when you enter separate rates; the what-if tables show the same rate on round prices or totals, with your own amount marked.
• Continue in the Discount Calculator takes the taxed amount and the rate along, to stack discounts before the tax. Continue in the Tip Calculator takes the total and the tax, so a restaurant tip can be figured on the price before tax.

Assumptions and limitations

• One combined rate applies to the whole taxed amount. The calculator doesn’t decide what is taxable in your state: enter only the taxed amount, or list items and mark the tax-free ones.
• Tax is rounded to the nearest cent, half a cent up, once on the taxed amount. Per-item and per-part roundings are shown for comparison.
• Rates are not looked up and must be at most 100%. Amounts are in whole cents, up to $1,000,000,000,000.
• Other charges and taxes, such as shipping, deposits, excise or lodging taxes, are not included unless you add them to the price.
• The result is an educational estimate, not tax advice.

Common mistakes

• Typing the rate as a decimal. The field is in percent, so 0.0775 means 0.0775%, not 7.75%. The calculator asks “Did you mean 7.75%?” when it sees a value like that.
• Taking the rate off a tax-included total. 7.75% of $269.36 is more than the tax in it; divide by 1.0775 instead.
• Leaving out local rates. A state rate alone understates the tax wherever county, city or district rates apply.
• Finding the rate from a subtotal with tax-free items in it. The rate comes out too low; use only the taxed items.
• Reading a one-cent gap as an error. Item-by-item, part-by-part and once-per-receipt rounding can differ by a cent or more, and each is correct for its method.