How to Calculate Sales Tax (Free, With Examples)
Sales tax is added on top of a price at checkout, and it's handy to know the total before you pay — or to work backward from a total to the pre-tax price. This guide shows how to calculate sales tax with simple formulas and examples, plus a free calculator for exact figures.
🧾 Try the Percentage Calculator now — freeOpen →Knowing the real total helps you budget, check receipts, and price your own products correctly. Sales tax varies by location, so being able to calculate it for any rate keeps you accurate wherever you are.
The sales tax formula
To find the tax amount: multiply the price by the tax rate as a decimal. On a $50 item at 8% tax, that's 50 × 0.08 = $4 tax. The total is the price plus the tax: $54. Or find the total in one step by multiplying by (1 + rate): 50 × 1.08 = $54.
So for any tax rate, the final price is price × (1 + rate). At 7% tax, multiply by 1.07; at 10%, multiply by 1.10. One multiplication gives you the checkout total.
Working backward from a total
Sometimes you have the tax-included total and want the pre-tax price — useful for expenses and accounting. Divide the total by (1 + rate). If a receipt shows $54 including 8% tax, the pre-tax price was 54 ÷ 1.08 = $50, and the tax was $4.
The calculator handles both directions, so you never have to guess.
Step-by-step
Common mistakes to avoid
Pro tips
Frequently asked questions
How do I calculate sales tax?
Multiply the price by the tax rate as a decimal for the tax amount, then add it — or multiply the price by (1 + rate) for the total.
How do I find the pre-tax price?
Divide the tax-included total by (1 + the rate). $54 at 8% tax = 54 ÷ 1.08 = $50 pre-tax.
Is the calculator free?
Yes — free with no sign-up, and it runs instantly in your browser.
Do I apply tax before or after a discount?
After the discount — discounts reduce the price, then tax is applied to the discounted amount.
What tax rate should I use?
Your local sales tax rate, which varies by state, region or country.
Sales tax is one quick multiplication: price × (1 + rate) gives the total, and total ÷ (1 + rate) gives the pre-tax price. Use your local rate, apply it after discounts, and let the free calculator handle the exact figures.