Sales Tax Calculator
Calculate sales tax and total price, or back out the pre-tax price from a total.
What is the Sales Tax Calculator?
This tool calculates sales tax two ways: forward, from a pre-tax price and tax rate to the final total; and in reverse, from a tax-included total back to the original pre-tax price and the tax amount hidden inside it.
Why the reverse calculation isn't just "subtract the rate"
A common mistake is subtracting the tax rate percentage directly from a tax-included total (e.g. treating $108 at 8% tax as "$108 − 8% = $99.36 pre-tax"), which is wrong. The correct reverse formula divides by (1 + rate): pre-tax price = total ÷ 1.08 = $100.00 exactly. The tax rate applies to the pre-tax amount, not the total, so subtracting a percentage of the total overcorrects.
Why we don't hardcode any tax rate
Sales tax rates vary enormously — by country, by US state (some states have no sales tax at all), by city or district-level add-on taxes, and sometimes by product category (many places exempt groceries or apply different rates to different goods). Rather than guess or embed a rate table that would be wrong for most users, this tool simply asks for your local rate.
How to use it
- Choose whether your number is the pre-tax price or the tax-included total.
- Enter the amount and your local sales tax rate.
- Read off the pre-tax price, tax amount and total.