Add or remove sales tax in seconds. This free sales tax calculator shows the tax and total on any price, and can also work backward from a tax-included total to the original price.
Results update automatically as you type. “Remove tax” extracts the tax from a tax-inclusive total.
How Sales Tax Calculator Works
Sales tax questions run in two directions: how much tax gets added to a price, or how much tax was already baked into a total. This free sales tax calculator handles both, switching between an "Add tax" and a "Remove tax" mode.
Formula: In Add tax mode: Tax = Amount × Rate ÷ 100, and Total = Amount + Tax. In Remove tax mode (working backward from a tax-included total): Subtotal = Total ÷ (1 + Rate ÷ 100), and Tax = Total − Subtotal.
- Mode — choose "Add tax" to calculate tax on a pre-tax amount, or "Remove tax" to extract the tax from a tax-included total
- Amount — the price you enter; it's treated as pre-tax in Add mode or as the tax-included total in Remove mode
- Sales tax rate — the tax percentage that applies where the purchase is made
Example Scenarios
| Mode | Amount | Tax Rate | Tax | Result |
|---|---|---|---|---|
| Add tax | $100.00 | 7% | $7.00 | Total: $107.00 |
| Add tax | $250.00 | 8.5% | $21.25 | Total: $271.25 |
| Remove tax | $107.00 | 7% | $7.00 | Subtotal: $100.00 |
| Remove tax | $54.00 | 8% | $4.00 | Subtotal: $50.00 |
| Add tax | $19.99 | 6% | $1.20 | Total: $21.19 |
Practical Tips for the Sales Tax Calculator
A sales tax calculator is only as accurate as the rate you enter, and in many places the right rate is less obvious than it looks.
- Combine every layer. In the US the total can include state, county, city and special district taxes, so use the combined rate for the address.
- Check what is taxable. Groceries, clothing or services are exempt or reduced in some areas.
- When removing tax, divide the total by one plus the rate; subtracting the rate as a percentage of the total gives the wrong original price. The sales tax calculator's reverse mode handles this for you.
Rounding can create a one-cent difference between the sales tax calculator and a receipt, since shops may round per item or per total. VAT systems work differently from US sales tax, but the sales tax calculator maths is the same once you know the rate. Business owners should check local rules before charging customers, and can use the sales tax calculator to double-check invoices. The Wikipedia sales tax article compares approaches around the world.
Sales Tax Calculator FAQ
How do I calculate sales tax backward from a total?
Switch the calculator to "Remove tax" mode and enter the tax-included total in the amount field along with the tax rate. It divides the total by (1 + rate/100) to find the pre-tax subtotal, then shows the tax as the difference.Why is my calculated tax slightly different from the receipt?
Small differences usually come from item-level rounding: some retailers round tax per line item rather than on the order total, which can shift the final cents. Mixed tax rates on a single receipt (e.g., some items exempt) will also change the total in ways a single flat-rate calculation can't replicate.Do I need to know my local tax rate to use this calculator?
Yes — sales tax rates vary by state, county, and city, and sometimes by product category, so you'll need to enter the combined rate that applies to your purchase location. Check your state or local revenue department's site if you're unsure of the exact rate.Can I use this for VAT or GST instead of US sales tax?
The math works the same way for any flat-rate consumption tax, since VAT and GST are also calculated as a percentage of a price. Just enter the applicable VAT/GST rate in the tax rate field.What's the difference between "Add tax" and "Remove tax" mode?
"Add tax" starts from a pre-tax price and calculates what you'll pay after tax is added. "Remove tax" starts from a tax-included total, such as a receipt total, and works backward to find the original pre-tax price and the tax amount.Does this calculator account for tax-exempt items?
No — it applies a single flat rate to the full amount you enter, so it assumes the entire amount is taxable. If part of your purchase is exempt, calculate the taxable portion separately before entering it.Related Calculators
If you're pricing a purchase across borders, try the GST / VAT calculator for value-added tax systems, check how much a markdown actually saves you with the discount calculator, or compare prices per unit with the unit price comparison calculator.