Sales Tax Calculator
Technical Calculation Methodology and Tool
Interactive Sales Tax Calculator
Calculate sales tax, final price, and pre-tax amount instantly for shopping, invoices, and retail pricing.
Sales Tax Calculator
Calculate sales tax, total price, or reverse sales tax instantly
A sales tax calculator helps you quickly work out how much tax will be added to a purchase, what the final checkout total will be, or how much of a total price was tax-free before tax was included. It is useful for shopping, invoices, pricing, retail, and budgeting.
How to Use This Calculator
- Choose Add Sales Tax to add tax onto a pre-tax price, or choose Reverse Sales Tax to remove tax from a total price.
- Enter the amount.
- Enter the sales tax rate or use a quick preset.
- The calculator instantly shows the tax amount, total, and breakdown.
What Is Sales Tax?
Sales tax is a percentage added to the price of goods or services at the time of purchase. The percentage varies by region, state, province, or country.
When you add sales tax, you calculate the tax on the pre-tax price and then add it to the original amount. When you reverse sales tax, you start with the final total and work backward to separate the tax from the pre-tax price.
The Sales Tax Formula
Step-by-Step Calculation
- Enter the pre-tax price or total price.
- Convert the tax rate to a decimal by dividing by 100.
- For adding tax, multiply the price by the tax rate decimal to find the tax amount.
- Add that tax amount to the original price to get the final total.
- For reversing tax, divide the total by 1 plus the tax rate decimal to find the pre-tax amount.
Worked Examples
An item costs $100 before tax. The sales tax rate is 5%.
Sales tax: $5.00. Final total: $105.00.
A product costs $79.99 before tax. The tax rate is 8%.
Sales tax: $6.40. Final total: $86.39.
A purchase is $250 before tax. The sales tax rate is 12%.
Sales tax: $30.00. Final total: $280.00.
Your receipt total is $108 and that includes 8% sales tax. What was the pre-tax amount?
Pre-tax price: $100.00. Sales tax included: $8.00.
Results Table
| Pre-Tax Price | Tax Rate | Sales Tax | Total Price |
|---|---|---|---|
| $50.00 | 5% | $2.50 | $52.50 |
| $79.99 | 8% | $6.40 | $86.39 |
| $100.00 | 10% | $10.00 | $110.00 |
| $250.00 | 12% | $30.00 | $280.00 |
Common Mistakes to Avoid
- Using the tax rate as a decimal incorrectly: Enter 8 for 8%, not 0.08.
- Adding the tax twice: Make sure you only add the tax amount once to the pre-tax price.
- Reversing tax the wrong way: Do not subtract the percentage directly from the total. Divide the total by 1 plus the tax rate decimal.
- Using the wrong regional tax rate: Tax rates differ by location, so confirm the correct rate before pricing.
Quick Answers
What is 5% sales tax on $100? $5.00.
What is the total price of $80 with 10% sales tax? $88.00.
What is 8% sales tax on $50? $4.00.
What was the pre-tax amount of a $108 total at 8% tax? $100.00.