Quick Answer: Calculate before-tax price, sales tax amount, after-tax total, or implied sales tax rate from any two known values.
How This Calculator Works
Sales tax is applied as a percentage of the taxable price. This calculator supports forward tax calculations, reverse tax extraction from a total, and implied rate calculations from before-tax and after-tax prices.
Worked Scenario: Scenario: Adding Sales Tax at Checkout
A customer buys an item listed at $100 and the applicable sales tax rate is 6.5%.
Scenario Inputs
- Before-tax price: $100
- Sales tax rate: 6.5%
- Sales tax amount: $6.50
Outcome: Multiplying 100 by 6.5% gives 6.50 of tax. Adding that tax to the price produces an after-tax total of $106.50.
Formula and Methodology
Sales tax amount = Before-tax price * Sales tax rate / 100
After-tax price = Before-tax price + Sales tax amount
Before-tax price = After-tax price / (1 + Sales tax rate / 100)
Implied tax rate = (After-tax price - Before-tax price) / Before-tax price * 100
Variables
- Before-tax price: The taxable price before sales tax is added
- Sales tax rate: The percentage tax rate applied to the taxable price
- Sales tax amount: The added tax amount
- After-tax price: The final amount including sales tax
Assumptions
- The entered rate is the combined applicable sales tax rate for the transaction.
- The full before-tax amount is taxable.
- Rounding is performed to two decimal places for currency-style display.
Limitations
- This calculator does not look up jurisdiction-specific tax rates or determine whether an item is exempt.
- Local, state, provincial, municipal, use tax, VAT, GST, discounts, and shipping rules must be handled by the user where applicable.
Practical FAQs
How do I add sales tax to a price?
Multiply the before-tax price by the tax rate as a decimal, then add the tax amount to the original price. For example, 100 at 6.5% tax becomes 106.50.
How do I remove sales tax from a total?
Divide the after-tax total by one plus the tax rate as a decimal. For example, 106.50 divided by 1.065 gives a before-tax price of 100.
Can I use this for VAT or GST?
The math is similar for many percentage-based transaction taxes, but VAT and GST rules can differ. Use the VAT calculator when you specifically need VAT-style gross-to-net or net-to-gross calculations.