Sales Tax Calculator
Sales Tax Terms
Tax Breakdown
| Before Tax (Net) | — |
|---|---|
| Tax Amount | — |
| After Tax (Gross) | — |
How to Use This Sales Tax Calculator
The register total never matches the shelf tag, and reverse-engineering a receipt at the end of the month is a headache. I built this around the two questions that come up constantly: what is the out-the-door price with tax, and what was the pre-tax amount when tax is already baked in?
- Choose a calculation mode. Add Tax starts from net price; Remove Tax extracts tax from a gross total.
- Enter the price. In Add Tax mode, enter net price. In Remove Tax mode, enter the gross price that already includes tax.
- Enter the tax rate. Use your combined state, county, and local rate as a single percentage (e.g. 8.25).
- Press Calculate. Review before-tax (net), tax amount, and after-tax (gross) in the breakdown table.
Converting international prices? Try the VAT Calculator for value-added tax scenarios, or the Currency Calculator for cross-border amounts.
Sales Tax Formulas and Practical Applications
Sales tax is a percentage of the taxable price added at checkout. Retailers quote net prices in some regions and tax-inclusive prices in others—knowing both directions saves surprises at the register.
Add tax (net to gross)
Tax = Net × (Rate ÷ 100)
Gross = Net + Tax
A $100 net item at 8.25% tax adds $8.25 tax for a $108.25 gross total.
Remove tax (gross to net)
Net = Gross ÷ (1 + Rate ÷ 100)
Tax = Gross − Net
A receipt showing $108.25 at 8.25% implies a net price of $100 and tax of $8.25.
When to use each mode
Use Add Tax when pricing inventory or quoting customers. Use Remove Tax when reconciling credit card statements, splitting a shared bill, or backing tax out of an invoice total for bookkeeping.
Frequently Asked Questions
How do I add sales tax to a net price?
Select Add Tax mode, enter the net price and tax rate. Tax equals net times rate divided by 100, and gross equals net plus tax.
How do I remove sales tax from a gross price?
Select Remove Tax mode and enter the gross price and tax rate. Net equals gross divided by one plus rate divided by 100.
Should I enter combined state and local tax rates?
Yes. Enter the total percentage you actually pay, including state, county, city, and district surcharges as one combined rate.
Is sales tax the same as VAT?
The math is similar for a flat rate, but VAT regimes may have exemptions and invoice rules this tool does not model.
Does this calculator include tax on tax?
No. This tool applies a single flat rate to the taxable amount. Compound or layered tax rules are not modeled.