How sales tax works
When tax is added, total = pre-tax price × (1 + tax rate ÷ 100). To extract included tax, divide the tax-inclusive total by (1 + tax rate ÷ 100).
Worked example
At an 8.5% rate, a $100 pre-tax purchase has $8.50 tax and a $108.50 total.
How to use this calculator
Enter the values above and select Calculate now. Change one input at a time to compare scenarios. Results are calculated in your browser; no account is needed.
Assumptions and limitations
This is an arithmetic estimate, not a determination of tax obligations. Actual receipts may differ because of rounding, exemptions and local rules.
Frequently asked questions
Can I calculate tax already included in a price?
Yes. Select “Yes — extract tax” and enter the tax-inclusive amount. The calculator separates the estimated base price and tax.
Is the rate the same everywhere?
No. Rates vary by jurisdiction, product and exemption. Enter the rate applicable to your purchase; this tool does not look up local rates.