Working backward from a tax-inclusive total to figure out the original pre-tax price trips people up more often than the forward calculation — you can’t just subtract the tax rate percentage, since that percentage was applied to a different (smaller) number.
What Is the Sales Tax Calculator?
A two-way calculator that either adds sales tax to a pre-tax price, or reverses the process — taking a tax-inclusive total and a tax rate to recover the original pre-tax price and tax amount.
How to Use It
- Open the tool at /tools/sales-tax-calculator.
- Choose “Add tax to price” or “Remove tax from total.”
- Enter the amount and tax rate.
- Read the tax amount and resulting total (or pre-tax price) instantly.
Key Features
- Two-way calculation, both adding tax forward and reversing it out of a total.
- Correct reverse-tax math, dividing by (1 + rate) rather than incorrectly subtracting the tax percentage.
- Works for any percentage-based tax, including VAT, GST, or combined state+local US sales tax rates.
- Instant, live recalculation as you type.
When to Use This Tool
- Checking a receipt or invoice, verifying the tax amount charged matches the stated rate.
- Pricing products for different tax jurisdictions, quickly seeing the final customer-facing price.
- Reverse-engineering a pre-tax cost from a tax-inclusive total for bookkeeping or expense reports.
Try It Now
Open Sales Tax Calculator directly, or press ⌘K and type the tool name from anywhere on the site.
Part of the Math & Numbers collection on WebdevToolbox — free, browser-based developer tools with no login required.