Sales Tax Calculator: Add or Remove Tax
This sales tax calculator adds tax to a price or removes tax already included in a total. Enter the amount and rate, then choose Add tax or Remove included tax to see the price before tax, tax amount, and final total.
It works with decimal rates and seven common currencies. The calculation happens in your browser. You still need the correct rate for the buyer’s location and item because this tool does not identify jurisdictions or decide whether a purchase is taxable.
Sales tax calculator
Add tax to a price or reverse an inclusive total.
Use the tax rate that applies to your location and product. This calculator works out the amount; it does not look up rates or determine taxability.
How to use the sales tax calculator
Choose the direction of the calculation first. Add tax starts with a price before tax. Remove included tax is the reverse sales tax calculator mode and starts with the amount someone actually paid.
- Pick Add tax or Remove included tax. The amount label and result change with the mode.
- Enter the amount, currency, and tax rate. Decimal rates such as 7.25 or 8.875 work.
- Read or copy the breakdown. The result separates the price before tax, tax amount, and total after tax.
This calculator handles percentage tax only. If you need to estimate payment processing costs instead, use the PayPal fee calculator.
Sales tax formula
The basic sales tax formula is tax amount = price before tax × tax rate. Convert the percentage rate to a decimal before multiplying, so 8.25% becomes 0.0825.
| What you need | Formula | Example at 8.25% |
|---|---|---|
| Tax amount | Price × 0.0825 | $100 × 0.0825 = $8.25 |
| Total after tax | Price × (1 + rate) | $100 × 1.0825 = $108.25 |
| Price before included tax | Total ÷ (1 + rate) | $108.25 ÷ 1.0825 = $100 |
| Tax included in total | Total − price before tax | $108.25 − $100 = $8.25 |
Keep the full precision during the calculation and round the final currency amounts once. Tax agencies can set their own rounding and invoice rules, so use the official rule for a return or customer invoice. The Texas A&M sales tax guide shows the same add-tax and reverse-tax method.
Worked sales tax examples
The fastest way to catch a sales tax mistake is to check the three numbers together. The tax amount plus the price before tax must equal the final total.
Add 8.25% sales tax to $100
- Price before tax: $100.00
- Tax amount: $8.25
- Total after tax: $108.25
Remove 8.25% included tax from $108.25
- Tax-inclusive total: $108.25
- Price before tax: $100.00
- Tax included: $8.25
Do not subtract 8.25% directly from $108.25. That would calculate 8.25% of the tax-inclusive total, not extract the tax that was added to the original $100 price.
Sales tax vs. VAT and GST
This tool can calculate a percentage added to or included in a price, whether the label is sales tax, VAT, or GST. The arithmetic overlaps, but the tax systems are not interchangeable.
| Tax system | How it is commonly collected | How to use this calculator |
|---|---|---|
| Retail sales tax | Usually collected from the buyer at the final taxable sale | Add tax to a listed pre-tax price |
| VAT | Collected at multiple stages, with input-tax rules for businesses | Add VAT or remove VAT included in a displayed total |
| GST | Collected under country-specific goods and services tax rules | Add GST or reverse GST from an inclusive amount |
The calculator does not determine exemptions, place-of-supply rules, filing treatment, or whether an input credit is available. Those are legal and accounting questions, not percentage math.
How to find the correct sales tax rate
Use the rate published by the government tax authority for the transaction. In the United States, that may be a combined state, county, city, and special-district rate rather than one statewide number.
- Check the tax agency for the buyer or delivery location.
- Confirm whether the product or service is taxable.
- Use the rate effective on the transaction date.
- Include local or special-district rates when the jurisdiction requires them.
For US businesses, the IRS maintains a directory of state government tax websites. For other countries, use the national revenue authority or your accountant. A calculator that guesses the rate from a country alone can give you the wrong answer.
Related business calculators
Sales tax is only one part of a transaction. Use the PayPal fee calculator for payment fees, the marketing ROI calculator for campaign profitability, or browse the full calculator library.
Sales tax calculator FAQ
What does a sales tax calculator do?
A sales tax calculator applies a percentage rate to a price or reverses tax already included in a total. This tool shows the price before tax, tax amount, and total after tax.
How do I calculate sales tax from a price?
Multiply the price before tax by the tax rate written as a decimal. For example, $100 at 8.25% produces $8.25 in tax and a $108.25 total.
How do I remove sales tax from a total?
Divide the tax-inclusive total by 1 plus the tax rate as a decimal. At 8.25%, divide $108.25 by 1.0825 to get a $100 price before tax. The remaining $8.25 is the included tax.
Does this calculator find my local sales tax rate?
No. Enter the current combined rate supplied by the government tax authority for the buyer or delivery location and the item being sold. This tool calculates amounts but does not identify jurisdictions or decide whether a purchase is taxable.
Can I use this as a VAT or GST calculator?
Yes, for the percentage calculation. Choose Add tax for a price before VAT or GST, or Remove included tax for a tax-inclusive total. VAT, GST, and retail sales tax have different legal and filing rules.
Can I enter a decimal sales tax rate?
Yes. Enter 7.25 for 7.25%, 8.875 for 8.875%, or another rate from 0 to 100. The calculator keeps full precision and formats the currency result.
Does the sales tax calculator store my data?
No. The calculation runs in your browser. The amounts and tax rate are not submitted to the website.