🧾 Sales Tax Calculator

What is the Sales Tax Calculator?

Sales tax is a percentage that a government adds to the price of goods and services. In the United States it is called sales tax and is usually added at the register on top of the listed price, so a $100 item at an 8.25% rate costs $108.25 at checkout. In most of Europe, Canada, Australia, and many other countries the equivalent is called VAT (value added tax) or GST (goods and services tax), and the rate is normally already included in the shelf price you see.

Adding tax is simple: multiply the net amount by the rate and divide by 100 to get the tax, then add it to the net amount to get the total. A $100 sale at 8.25% gives $8.25 of tax and a $108.25 total. The harder direction, and the one people get wrong, is working backwards from a tax-inclusive price to find the original amount. You cannot just subtract the rate, because the rate was applied to the smaller net figure, not the larger total.

To extract tax from a tax-inclusive total you divide by one plus the rate as a decimal: net = total / (1 + rate / 100). For a $108 total at an 8% inclusive rate, net = 108 / 1.08 = $100.00, so the tax portion is $8.00. This reverse calculation is exactly what you need when you have a gross receipt and have to report the net sale and the tax separately, which is common for bookkeeping, VAT returns, and expense claims.

When to use it

• Adding US sales tax to a price so you know the real checkout total before you buy.
• Extracting the VAT or GST from a tax-inclusive receipt for bookkeeping or a tax return.
• Quoting a customer a net price plus tax, or working out the net from a gross invoice total.
• Comparing how different state or country tax rates change the final price of the same item.

How to use the Sales Tax Calculator

1. Choose "Add tax" to put tax on top of a net price, or "Extract tax" to pull tax out of a tax-inclusive total.
2. Enter the amount: the net price in Add mode, or the tax-inclusive total in Extract mode.
3. Type the tax rate as a percentage, or tap one of the quick-rate buttons.
4. Read off the net amount, the tax amount, and the total with tax.

Formula & method

Worked examples

Common tax rates by region (illustrative, check current local rates)

Add tax vs extract tax at a 10% rate

Common mistakes to avoid

• Subtracting the rate to remove tax. To take 20% VAT off a £120 total, people subtract 20% (£24) and get £96, which is wrong. The tax was applied to the smaller net amount, so you must divide by 1.20, giving £100 net and £20 tax.
• Mixing up the net price and the tax-inclusive total. In Add mode the amount you type is the price before tax. In Extract mode it is the price that already includes tax. Entering the wrong one gives a tax figure that is off in either direction.
• Assuming the listed price already includes tax. In the US, sales tax is usually added at the register, so the shelf price is the net amount. In most VAT and GST countries the price already includes tax. Know which applies before you calculate.
• Using a stale or wrong local rate. Combined US sales tax varies by state, county, and city, and VAT or GST rates change over time. Always confirm the current rate for the exact location rather than reusing an old figure.

Glossary

Sales tax

A percentage tax added to the price of goods and services, typically added at checkout in the United States.

VAT

Value added tax, a consumption tax used across the UK, EU, and many other countries, usually included in the displayed price.

GST

Goods and services tax, a broad consumption tax used in countries such as Australia, Canada, and India.

Net amount

The price before any tax is added. Tax is calculated as a percentage of this figure.

Gross amount

The tax-inclusive total: the net amount plus the tax on it.

Frequently asked questions