Enter a price and sales tax rate to see the tax amount and total, or switch to reverse mode to back out the pre-tax price from a total that already includes tax.
Amount: Tax rate (%):
Mode:
How It Works
In the default mode, the calculator multiplies your price by the tax rate to get the tax amount, then adds it to get the total. In reverse mode, it divides the tax-included total by (1 + rate) to find the original pre-tax price.
How to Use This Tool
- Enter the price and the local sales tax rate.
- Choose whether the amount you entered already includes tax.
- Click Calculate to see the breakdown.
Sales tax rates vary by state, county, and city in the US, and by country elsewhere; check your local rate if you are not sure of it.
The Formulas
- Add tax: tax = price × rate, and total = price + tax (or price × (1 + rate)).
- Reverse (tax already included): pre-tax price = total ÷ (1 + rate), and tax = total − pre-tax price.
Worked example (add tax): a 100 purchase at an 8% rate has tax of 100 × 0.08 = 8, for a total of 108.
Worked example (reverse): your receipt shows a total of 108 and you know the rate was 8%. The pre-tax price is 108 ÷ 1.08 = 100, so the tax was 8.
A Common Mistake When Backing Out Tax
Many people try to remove tax by taking the tax rate off the total. With a total of 108 and an 8% rate, that gives 108 × 0.08 = 8.64, and 108 − 8.64 = 99.36. That is wrong, because the 8% was applied to the smaller pre-tax price, not to the total. Dividing by 1.08 is the correct method, and it is exactly what reverse mode does for you.
Sales Tax, VAT, and GST
In the United States, sales tax is usually added at the register, so the shelf price is lower than what you pay. In many other countries, prices on the shelf already include value-added tax (VAT) or goods and services tax (GST). The same math applies to both, so this calculator works with a VAT or GST rate as well. If a price already includes VAT, use reverse mode to see how much of it is tax. Rates and rules differ by location and product type, so check your local rate for anything important.
Did You Know?
- Some US states have no statewide sales tax at all, including Oregon, Montana, and Delaware.
- A receipt that lists a total “including tax” is exactly the kind of figure the reverse mode here is built to unpack.
Frequently Asked Questions
Why would I use reverse mode?
Reverse mode is useful when you only know a final total that already includes tax (like a receipt total) and want to know the original price before tax.
Does this handle combined state and local tax rates?
Yes, just enter your total combined rate (state plus any county or city tax) as a single percentage.
Where can I find my local sales tax rate?
Check your state or local revenue department’s website, or look at a recent receipt from a nearby store, which usually shows the tax rate. Remember to use the combined rate if state, county, and city taxes all apply.
Are all items taxed at the same rate?
Not always. Some places tax groceries, clothing, or prepared food at a lower rate, or not at all. If your item has a special rate, enter that rate instead of the general one.
Is this tax advice?
No. This is a general math tool for estimating everyday purchases. For business tax filing or legal questions, consult a qualified tax professional.