Free Sales Tax Calculator — Add or Remove Tax
Add sales tax to a price, or back it out of a tax-included total — both directions, one tool.
Example result
- You enter
- Pre-tax amount
- $240.00
- Sales tax rate
- 7.5%
- You get
- Sales tax
- $18.00
- Total
- $258.00
Fictional numbers, to show how the result is laid out.
How it works
Adding tax to a price is simple multiplication — Price × (1 + Tax Rate). Going the other direction, figuring out how much of a tax-included total was actually tax, is where people get it wrong: dividing by (1 + Tax Rate) instead of just subtracting a percentage, since the tax was calculated on the pre-tax amount, not the final total.
This comes up most often for small business owners reconciling a receipt or invoice where only the final total was recorded, or checking that a point-of-sale system applied the correct combined state-and-local rate. Rates vary by state, county, and sometimes city in the US, so there's no single number to memorize — check your state's Department of Revenue site for the exact combined rate that applies to your location.
A worked example at a hypothetical 7.5% rate: $240.00 plus tax of $18.00 makes $258.00. To go the other way, divide the tax-inclusive total by 1.075, so $258.00 / 1.075 = $240.00. Multiplying the total by the rate instead would give the wrong tax.
Use the rate that applies to your location and product, because rates and what is taxable vary. Your state tax agency or an accountant can confirm it. This tool does arithmetic and does not decide what is taxable.
Who uses this
| Business type | How it's used |
|---|---|
| Retail stores | Add local sales tax to a sticker price, or back it out of a tax-included price to see the pre-tax revenue. |
| Restaurants & cafes | Work out the tax-inclusive price on a menu, or check how much of a check total is tax versus food revenue. |
| Pop-up shops & market vendors | Quickly add tax to a cash-sale price at a farmers market or craft fair without a register. |
| E-commerce sellers | Check the tax due on an order from a customer's state or local rate. |
| Service contractors | Add tax to a taxable service or materials line on an invoice before sending it to a client. |
| Salons & barbershops | Check whether a taxable retail product sold in-chair (styling product, merchandise) has the right tax added. |
| Flower shops | Add sales tax to an arrangement price, since floral purchases are taxable in most states. |
Frequently asked questions
Q.How do I find my local sales tax rate?
Sales tax rates are set at the state and often city/county level in the US, so they vary by location. Check your state's Department of Revenue website for the exact combined rate for your area.
Q.Is this a substitute for tax filing software?
No — this is a quick estimate for pricing and checkout math, not a filing tool. Talk to an accountant or use dedicated tax software for actual filings.
Q.Is this the same as an online sales tax calculator?
Yes — sales tax calculator, sale tax calculator, and online sales tax calculator all describe the same tool. It works both ways: use it to calculate sales tax on a pre-tax price, or to see how to add sale tax and back it out of a tax-included total.