Add tax to a price or extract it from a total
Sales tax, VAT, GST — whatever it is called in your country, the arithmetic is always one of two operations: adding a tax percentage to a net price to get the gross amount a buyer pays, or working backwards from a gross price to find out how much of it is tax. This calculator handles both instantly. Enter the amount, the tax rate, and choose a mode; the net, tax amount, and gross update as you type.
Understanding which direction you need is the first step. If you are a seller pricing a product and you want the displayed price to be the pre-tax amount with tax added at checkout, choose "add tax." If you received a receipt or an invoice and want to know how much of that total was tax, choose "extract tax." Both are everyday needs and both follow from the same simple formula.
How to use the calculator
Enter the price in the amount field. For "add tax" mode this is the pre-tax (net) price. For "extract tax" mode this is the total (gross) price you see on the receipt. Next, enter the tax rate as a plain number — for example, enter 20 for a 20% rate. Choose the mode from the dropdown and read the three output values: net (pre-tax), the tax amount itself, and gross (total with tax). The result refreshes instantly with every keystroke.
The formulas behind it
When adding tax, the gross price equals the net price multiplied by one plus the rate divided by one hundred. A £100 item at 20% becomes £120. The tax portion is £20.
When extracting tax, the net price equals the gross price divided by one plus the rate divided by one hundred. A £120 total at 20% gives a net of £100 and tax of £20. That division step is the one people frequently get wrong — dividing by 1.20, not subtracting 20% of the gross directly, which would give a different and incorrect answer.
Common tax rates around the world
Tax rates vary enormously by country and even within countries. In the United Kingdom the standard VAT rate is 20%, with reduced rates of 5% on some items. Germany applies 19% to most goods and 7% to food and books. Australia charges 10% GST on most goods and services. Canada has a federal GST of 5% plus provincial rates. In the United States there is no federal sales tax; rates are set by states and localities and range from 0% in some states to over 10% in some cities when combined. Always verify the rate that applies to your specific situation before using it for any official purpose.
When extracting tax matters most
The extract-tax calculation is particularly useful when you are reconciling accounts, claiming back input VAT as a business, or trying to compare prices across different markets where some prices are shown with tax and others without. It also comes up in personal finance when you want to understand the true pre-tax cost of something, such as when comparing offers where one seller shows a tax-inclusive price and another shows a tax-exclusive one.
Compound rates and multiple taxes
Some transactions are subject to more than one tax — for example a hotel stay that carries both a state tax and a local tax. To handle this, calculate the first tax on the net price and then apply the second tax to that intermediate total, treating it as the new "net." The order generally does not matter when both rates apply to the same base, but it does matter when taxes are applied sequentially to a growing base. For simple combined rates, you can just add the percentages together before entering them if they both apply to the same base amount.
A worked example both ways
Suppose a laptop is priced at £850 net and the applicable VAT rate is 20%. Adding tax: £850 × 1.20 = £1,020 gross, with £170 of that being tax. Now suppose instead you are handed a receipt showing £1,020 as the total and need to know the pre-tax price for your accounts. Extracting tax: £1,020 ÷ 1.20 = £850 net, again with £170 of tax. Both directions describe the same transaction, which is a useful way to check your own arithmetic — whichever direction you calculate first, converting back the other way should return you to where you started.
A common mistake is to take 20% of the gross figure directly and call that the tax, which for £1,020 would wrongly suggest £204 rather than the correct £170. The error creeps in because the 20% rate is defined relative to the net price, not the gross one, so it must be applied before tax is added, or removed via division rather than a flat percentage subtraction afterwards. This calculator always uses the correct relationship, so you can rely on the figures without re-deriving the formula each time.
Private, instant and free
No data you enter is sent anywhere. The calculator is a small piece of JavaScript that runs entirely on your device. It works offline, responds instantly, and does not require any account or registration. Close the tab and every number you typed is gone.
Use this tool whenever you price a product, reconcile a receipt, or need to separate the tax component from a total. The three outputs — net, tax, and gross — give you the complete picture in a single view.
Sales tax calculator FAQ
- What is the difference between adding and extracting tax?
- Adding tax takes a net price — the price before tax — and calculates the gross price you pay. Extracting tax does the reverse: you enter the gross price already including tax and the calculator works out how much of it is tax and what the pre-tax amount was.
- What tax rates should I use?
- Use whatever rate applies in your country or region. Common examples include 20% VAT in the UK, 19% in Germany, 10% GST in Australia, and varying sales tax rates by US state. Enter the number without the percent sign.
- Is anything I type uploaded?
- No. Everything runs in your browser with no server involved. The figures you enter disappear when you close the page.