Sales Tax Calculator

Add sales tax onto a price, or back the pre-tax price out of a tax-included total; enter a price and tax rate and get both figures instantly, in your browser.

runs locally on your browser. Your data never leaves your device.

Mode

Total With Tax

$54.00

$4.00 tax on $50.00

$4.00Tax Amount
$54.00Total With Tax

Common Use Cases

Work out the final price and tax amount before buying something, given a local sales tax rate
Back the pre-tax subtotal out of a tax-included receipt total for an expense report or bookkeeping entry
Price a product for a specific tax jurisdiction and see exactly what a customer will pay at checkout
Double-check that a receipt or invoice's tax calculation matches the stated tax rate

About Sales Tax Calculator

Sales tax math comes up constantly: checking out at a register, pricing a product before tax gets added at checkout, or reading a receipt and trying to work out what the item actually cost before tax was tacked on. The two directions of that problem use different formulas, and the reverse direction in particular is easy to get wrong: a price that already includes tax can't simply be reduced by the tax rate, because the tax rate was applied to the smaller, pre-tax number in the first place.

This calculator covers both directions as separate modes, selected with the toggle at the top. Add Tax to Price answers "what will I actually pay?" It takes a pre-tax price and a tax rate and computes the tax amount as price × (rate ÷ 100), then adds that to the price for the total. This is the everyday calculation behind a price tag that doesn't already include tax.

Price Includes Tax: Back It Out answers the opposite, less obvious question: "this total already includes tax, so what was the price before it was added?" You can't just subtract the tax rate from the total; the correct formula is pre-tax price = total ÷ (1 + rate ÷ 100). This comes up when reading a receipt or an all-in price and needing to know the pre-tax subtotal, for example for an expense report or a bookkeeping entry.

Both modes update their results live as you type, with no "Calculate" button to press, and the tax rate accepts any non-negative percentage including decimals (like a combined state-plus-local rate of 8.25%). Every calculation runs as plain JavaScript directly in your browser, so nothing you type is ever sent to a server, logged, or stored anywhere.

Frequently Asked Questions

How is the tax amount calculated when adding tax to a price?
The tax amount is the price multiplied by the tax rate, divided by 100: price × (rate ÷ 100). For example, 8% tax on a $50 item is 50 × 0.08 = $4, for a total of $54.
How do I work out the pre-tax price from a total that already includes tax?
Divide the tax-included total by (1 plus the tax rate as a decimal): pre-tax price = total ÷ (1 + rate ÷ 100). For example, a $54 total at 8% tax means the pre-tax price was 54 ÷ 1.08 = $50. Simply subtracting 8% from $54 would give the wrong answer, because the original 8% tax was calculated on the smaller $50 price, not on $54.
Why can't I just subtract the tax percentage from a tax-included total?
Because the tax rate was applied to the pre-tax price, not to the total. Subtracting the rate directly from the total (e.g. taking 8% off $54) removes too much, since 8% of $54 is larger than the $4 of tax that was actually added to the original $50 price. Dividing by (1 + rate ÷ 100) is the only way to correctly reverse the calculation.
Can I enter a combined state and local tax rate, or a decimal rate?
Yes. The tax rate field accepts any non-negative number, including decimals, so you can enter a combined rate like 8.25% (a common combined state-plus-local rate in parts of the US) directly, without needing to add the state and local rates together first.
Which mode should I use if I'm pricing a product before checkout adds tax?
Use "Add Tax to Price": enter the price before tax and the applicable tax rate, and the tool shows the tax amount and the final total the customer will pay.
Is my price data sent to a server?
No. Every calculation happens with plain JavaScript directly in your browser. Nothing you type is ever uploaded, logged, or stored anywhere.

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