Sales Tax Calculator (Add or Remove Tax)
Add sales tax, VAT or GST to a price, or work backwards from a tax-inclusive total to the pre-tax price.
How to add sales tax: price with tax = price × (1 + rate). How to remove it: price before tax = total ÷ (1 + rate). The tax is the difference.
Example: a $249.99 item at an 8.875% rate: $249.99 × 1.08875 = $272.18, of which $22.19 is tax. Removing tax divides; it does not subtract the rate, because the rate applies to the pre-tax price.
Work out any share of a total with the percentage calculator, or a sale price with the discount calculator.
Build your scenario
Use your actual figures where available. The output is an educational estimate based on the assumptions below.
Displayed amounts are rounded to two decimal places. Keep the same currency and time period across related inputs.
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How this calculator works
Adding tax multiplies the pre-tax price by (1 + rate). Removing tax, often called a reverse sales tax calculation, divides the tax-inclusive total by (1 + rate). Subtracting the rate from the total gives the wrong answer, because the tax was charged on the smaller pre-tax amount. The same maths works for U.S. state and local sales tax, European VAT and GST in countries such as Singapore, as long as one rate applies to the whole amount.
Sales tax formula: add and remove tax
Price before tax = total ÷ (1 + rate)
Tax = price with tax − price before tax
Worked examples: adding and removing sales tax
| Question | Rate | Before tax | Tax | Total |
|---|---|---|---|---|
| Add tax to a $249.99 item | 8.875% | $249.99 | $22.19 | $272.18 |
| Remove tax from a $59.95 receipt | 7.25% | $55.90 | $4.05 | $59.95 |
| Remove 9% GST from $129.00 | 9% | $118.35 | $10.65 | $129.00 |
Note the reverse case: 7.25% of $59.95 is $4.35, but the tax actually included is only $4.05.
Common mistakes
- Subtracting the tax rate from a tax-inclusive total instead of dividing.
- Using only the state rate when local taxes also apply. Combined rates vary by location.
- Applying one rate to items that are taxed differently or exempt.
- Expecting an exact match to a till receipt. Stores may round tax per item, not per total.
Sources
- Tax Foundation – State and local sales tax rates
- European Commission – VAT rates
- IRAS (Singapore) – Goods and Services Tax
Malaysia and Singapore notes
- Singapore GST has been 9% since 1 January 2024. Illustration: S$100 before GST is S$109 with GST, and S$109 including GST contains S$9 of GST. See IRAS.
- Malaysia SST is two taxes. Sales tax applies to taxable goods at 5% or 10%, and service tax applies to taxable services, generally at 8% with some services at 6%. Illustration: an RM100 taxable service at 8% costs RM108. See the Royal Malaysian Customs SST portal for which goods and services are taxable.
Related calculators
- Discount calculator — sale price after a percentage off
- Percentage calculator — percent of, change and reverse
- Markup calculator — selling price from cost
Related education
- How sales commission is calculated — whether commission is paid on sales before or after tax and returns.
- How to calculate percentages, including reverse percentages
- How discounts affect selling price
Frequently asked questions
How do I calculate sales tax backwards?
Divide the total by (1 + rate). For 8% tax, divide by 1.08. The difference between the two amounts is the tax.
Does this work for VAT and GST?
Yes, as long as a single rate applies. Choose add or remove depending on whether your price already includes tax.
Why doesn't it exactly match my receipt?
Shops may round tax per item, and some items can be exempt or taxed at a different rate.
Where can I find my sales tax rate?
For U.S. combined state and local rates, see the Tax Foundation's table or your state revenue department. Other countries publish VAT or GST rates through their tax authority.
How do I add sales tax to a price?
Multiply the price by (1 + tax rate). A $249.99 item at 8.875% costs $249.99 × 1.08875 = $272.18.
How do I work out the price before tax from a total?
Divide the total by (1 + tax rate). Subtracting the rate from the total gives the wrong answer, because tax is charged on the pre-tax price.
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