Sales Tax Calculator
Provide any 2 values below to calculate before-tax price, tax rate, or total price including sales tax.
Provide any 2 values and click Calculate.
Formulas
After = Before × (1 + Rate% / 100)
Tax = After − Before
Tax = After − Before
How to use this sales tax calculator
- Enter any two of: before-tax price, tax rate, or after-tax total.
- Leave the third field blank — it will be calculated for you.
- Click Calculate to see the total, tax amount, and step-by-step breakdown.
Sales tax formulas
Total with tax = Before-tax price × (1 + Tax rate ÷ 100)
Before-tax price = Total ÷ (1 + Tax rate ÷ 100)
Tax rate = ((Total ÷ Before-tax price) − 1) × 100
Example: A $100 item at 8% tax costs $108 total ($8 in tax).
Real-world uses
- Shopping: Estimate your checkout total before you reach the register.
- Business invoicing: Add the correct tax rate to line items on quotes and invoices.
- Receipt verification: Work backward from a receipt total to confirm the tax rate applied.
- Cross-state comparison: Compare effective prices in regions with different tax rates.
Frequently Asked Questions
Any 2 of the 3 fields — before-tax price, tax rate, or after-tax total — are enough to calculate the third.
Yes. Enter the before-tax subtotal and the after-tax total. The calculator solves for the tax rate percentage.
Yes. Enter the applicable percentage rate whether it is called sales tax, VAT, or GST — the math is the same.