Sales Tax Calculator

Add or remove state and local sales tax at any rate: see the tax amount and the price with and without tax.

Sales tax

$7.50

Add tax

Before tax

$100.00

Including tax

$107.50

Please note: This is an example calculation, not financial advice. Personal circumstances, changes in rules and rates, and additional costs are not included. If in doubt, talk to a financial adviser.

How this number is calculated

The blocks use your input. Change a value above and they update with it.

Step 1 · Rate as a factor

Sales tax rate (%)7.5 ÷ Per100 =Rate as a factor0.075

Step 2 · Amount before tax

(Calculation: Add tax) Amount$100.00 =Amount before tax$100.00

Step 3 · Sales tax

Amount before tax$100.00 × Rate as a factor0.075 =Sales tax$7.50

Step 4 · Including tax

Amount before tax$100.00 + Sales tax$7.50 =Including tax$107.50

How the calculation works

Calculate how much sales tax is in a price, or what a price becomes once sales tax is added. Enter any rate, so it works for every state, county and city, and for VAT in other countries.

Add tax: the tax is the amount times the rate, and the price including tax is the amount plus the tax. Remove tax: the amount before tax is the amount divided by (1 + rate); the difference from the amount you entered is the tax. All results are rounded to whole cents, with half a cent rounded up.

Formula

Add tax: tax = amount × rate ÷ 100. Remove tax: before tax = amount ÷ (1 + rate ÷ 100), tax = before tax × rate ÷ 100.

Assumptions

One tax rate applies to the whole amount.
The rate you enter is the full rate, for example state, county and city sales tax added together.
Each result is rounded to whole cents, with half a cent rounded up.
Exemptions and other special rules are not included.

Example calculations

The button fills in the calculator above, so you can carry on from there.

Invoice, adding 20% VAT

Sales tax
$170.00

Amount $850.00 · Sales tax rate (%) 20 · Add tax
Receipt, taking out 20% VAT

Sales tax
$4.00

Amount $23.99 · Sales tax rate (%) 20 · Remove tax
Sales tax at checkout

Sales tax
$16.25

Amount $249.99 · Sales tax rate (%) 6.5 · Add tax

Frequently asked questions

How do I remove sales tax from a price?

Divide the price including tax by 1 plus the rate as a decimal. With 8% sales tax, divide by 1.08: a total of 54 is 50 before tax, so the tax is 4.

Why is 8% of the total including tax not the tax?

The rate applies to the price before tax. On a total of 54 including 8% sales tax, the tax is 4: that is 8% of 50, not 8% of 54.

How is sales tax different from VAT?

Sales tax is added at checkout and is usually not included in the price on the shelf. The rate depends on the state and often the city or county, so combine both into one rate here. VAT is charged at every step of the supply chain and is normally already included in consumer prices.

How do I add sales tax to a price?

Multiply the price by the tax rate as a decimal and add the result to the price. With 8% sales tax, 50 becomes 50 + 50 × 0.08 = 54.

What is GST?

GST (goods and services tax) is the name used for VAT in countries such as Australia, New Zealand, Canada and Singapore. It is calculated the same way, so you can enter the GST rate here.

Why is my receipt off by a cent?

Stores may round the tax per item instead of over the total, which can make a difference of a cent or two. This calculator figures out the tax over the whole amount and rounds the result to the cent.

Sources and checks

Sources

Detailed Description of the Sales and Use Tax Rate | CDTFA (opens in a new tab)cdtfa.ca.gov · accessed October 5, 2026
State and Local Sales Tax Rates, Midyear 2026 | Tax Foundation (opens in a new tab)taxfoundation.org · accessed October 6, 2026

How we check it

This calculator has 14 fixed checks: 11 calculations with a result that is fixed in advance, and 3 cases of invalid input that must be rejected. They all run automatically every time we publish; if one fails, the calculator does not go live.

See the calculations

Amount $100.00 · Sales tax rate (%) 20 · Add tax → Sales tax $20.00
Amount $120.00 · Sales tax rate (%) 20 · Remove tax → Sales tax $20.00
Amount $50.00 · Sales tax rate (%) 7.25 · Add tax → Sales tax $3.63
Amount $10.99 · Sales tax rate (%) 5 · Add tax → Sales tax $0.55
Amount $10.00 · Sales tax rate (%) 19 · Remove tax → Sales tax $1.60
Amount $50.00 · Sales tax rate (%) 0 · Remove tax → Sales tax $0.00
Amount $0.00 · Sales tax rate (%) 20 · Add tax → Sales tax $0.00
Amount $1,000,000,000.00 · Sales tax rate (%) 100 · Add tax → Sales tax $1,000,000,000.00
Amount $850.00 · Sales tax rate (%) 20 · Add tax → Sales tax $170.00
Amount $23.99 · Sales tax rate (%) 20 · Remove tax → Sales tax $4.00

Changes

October 6, 2026: Separate default tax rates for the UK and the US, with a source for the average US sales tax rate.
October 5, 2026: Sources added and content reviewed.
October 4, 2026: First version.

Last reviewed: October 6, 2026 · How we build and check our calculators