Sales Tax Calculator

What this calculator does

This tool handles sales tax in both directions. In Add tax mode, you enter a pre-tax subtotal and a tax rate, and it shows the tax amount plus the final total a customer pays. The formula is simple: total = subtotal × (1 + rate). In Remove tax mode you do the reverse — you already know the tax-inclusive total (say, a receipt total or an all-in listing price) and you want to pull out the original pre-tax amount and how much of that total was tax. That uses subtotal = total ÷ (1 + rate), then tax is whatever is left over.

When reverse mode is handy

Reverse tax is useful when a price is quoted "tax included" and you need to break it down — for bookkeeping, expense reports, invoicing, or figuring out the true product cost behind a rounded shelf price. Sellers use it to back out tax from a flat all-in price so their books show the correct taxable base.

How to use it

1. Pick a mode: Add tax to build a total from a subtotal, or Remove tax (reverse) to break a total apart.
2. Type the dollar amount — your pre-tax subtotal in Add mode, or the tax-included total in Remove mode.
3. Enter your sales tax rate as a percentage, like 8.25 for 8.25%.
4. Read the results instantly: subtotal, sales tax, and total. Nothing is sent anywhere — the math runs entirely in your browser.

FAQ

What tax rate should I enter?

Use your combined state and local sales tax rate for the point of sale. Rates vary by location, so check your local rate — this tool does not look it up for you.

How does reverse (tax-inclusive) mode work?

It divides the total by 1 + rate to recover the pre-tax amount, then treats the remainder as tax. So a $108.25 total at 8.25% gives a $100.00 subtotal and $8.25 tax.

Why might my total be a cent off a receipt?

Stores round each line or the final tax to the nearest cent, and rounding rules differ. Results here are estimates for quick math, not official tax filings.

Is my data uploaded anywhere?

No. Every calculation happens locally in your browser — nothing you type is stored or sent to a server.