Sales Tax CalculatorCalculators
Add sales tax to a price or remove it from a total.
How to calculate sales tax from total when the receipt already includes it
A receipt shows $108.25 and you need the price before tax for an expense report or a bookkeeping entry. Taking the rate off the total gives the wrong answer, so work it backwards.
Why taking the rate off the total gives the wrong price
Sales tax is calculated on the net price. At 8.25%, a $100 item costs $108.25, and the $8.25 is 8.25% of $100. Take 8.25% off $108.25 instead and you get $99.32, which is 68 cents short. That is small on one receipt, but the same error repeats on every line of an expense report or a quarter of sales records.
The fix is to divide. The total equals the net price times 1 plus the rate, so the net price is the total divided by 1 plus the rate. VAT and GST work the same way.
Take the tax out, then check the rate
Open the Sales Tax Calculator and choose Take tax out of a total. Enter the total and the rate, and it shows the net price, the tax, and the total side by side. A $108.25 receipt at 8.25% gives a net price of $100.00 and $8.25 in tax. The same page adds tax to a price when you choose Add tax to a price: $80 at 8.25% comes to $86.60. You enter the rate yourself, because local rates change and some items are taxed differently.
If you know the price before tax and the tax but not the rate, use the Percentage Calculator. In the row X is what percent of Y, enter the tax as X and the net price as Y. $8.25 out of $100 gives 8.25%. Use the net price here, because $8.25 out of the $108.25 total is about 7.62%, which is not the rate the store charged.
Calculate sales tax from a total
- Write the tax rate as a decimal. 8.25% is 0.0825.
- Add 1 to it: 1.0825.
- Divide the total by that number. $108.25 ÷ 1.0825 = $100.00, the price before tax.
- Subtract the price before tax from the total to get the tax: $108.25 − $100.00 = $8.25.
- Check the result in the Sales Tax Calculator with Take tax out of a total.
What these calculators can't settle for you
- You enter the rate. Local rates change and some items are taxed differently.
- Rounding is done once on the total. A store that rounds per item can differ by a cent.
- A receipt that mixes taxed and untaxed items needs the taxed part on its own. Dividing the whole total gives the wrong net price.
- Neither calculator looks up the rate for an address.
Frequently asked questions
How do I find the price before tax from a total?
Divide the total by 1 plus the rate. $108.25 ÷ 1.0825 = $100.
Why can't I just take the tax percentage off the total?
The tax was charged on the net price, not on the total. Taking 8.25% off $108.25 gives $99.32, 68 cents short of the real $100.
How do I work out the sales tax rate from a receipt?
Divide the tax by the price before tax and multiply by 100. $8.25 ÷ $100 × 100 = 8.25%.
Does this work for VAT and GST?
Yes. VAT and GST use the same math. Enter your country's rate.
Related tools
Tools used in this guide
Percentage CalculatorCalculators
Answers the three basic percentage questions, each in its own row.
