Sales Tax Calculator

What is a sales tax calculator?

A sales tax calculator turns two numbers — an amount and a tax rate — into the three figures you actually need on a receipt or an invoice: the net price, the tax on it and the total. It works both directions. In add mode you start from a pre-tax price and find the total a customer pays; in remove mode you start from a tax-inclusive gross total and work back to the net and the tax hidden inside it. That reverse calculation is the one people most often get wrong by hand.

How sales tax is worked out

There are two formulas, and the calculator picks the right one based on the mode you choose.

1. Adding tax. The tax is the net price multiplied by the rate, and the total is the net plus that tax:
   • tax = net × rate ÷ 100
   • total = net + tax
2. Removing tax. The gross total already contains the tax, so you can't simply subtract the percentage. Instead you divide by one plus the rate to recover the net, then subtract:
   • net = total ÷ (1 + rate ÷ 100)
   • tax = total − net

Both modes fill in the same net / tax / total breakdown, so whichever way you start, you always see all three numbers.

Common sales tax rates

Rates vary a lot by place, which is why the calculator offers a few quick presets:

• 5% — a common flat or reduced rate in several countries.
• 7.25% — a widely quoted US base rate.
• 8.875% — a combined state-and-local rate used in some US cities.
• 10% — a round national rate seen in many countries.
• 20% — a standard rate in much of Europe (there it's usually called VAT).

Tap a preset or type your own exact rate — including fiddly ones with three decimal places.

How to use it

1. Pick your currency (display only — it doesn't change the maths).
2. Choose a mode: Add tax if you have a net price, Remove tax if you have a gross total.
3. Type the amount — the net price in add mode, or the tax-inclusive total in remove mode.
4. Enter the tax rate, or tap a preset.
5. Read the net, tax and total in the breakdown, and use Copy to grab a one-line summary.

A worked example

Say a customer is billed a $108.88 gross total and you need the net and the tax for your books, at an 8.875% rate. Switch to remove mode:

• Net: 108.88 ÷ (1 + 0.08875) = $100.00
• Tax: 108.88 − 100.00 = $8.88
• Total: $108.88 (unchanged — it was your input)

Add the tax back in add mode from $100.00 and you land on the same $108.88, which is the quick sanity check that the reverse formula is right. If you're working with European VAT specifically, the VAT Calculator uses the same idea; to knock a coupon off first, reach for the Discount Calculator; and for any other share-of-a-number question, the Percentage Calculator is a click away.

A note on accuracy

This is a straightforward single-rate calculation. Real invoices can layer several taxes, apply different rates to different line items, or round each line separately, so a multi-line receipt might differ by a cent or two from a single all-in figure. Treat the result as a clean, fast estimate and follow your local rules for rounding and for which rate applies to which goods.

Private by design

The whole calculation runs in your browser with plain JavaScript. Your amounts and rates are never uploaded, stored or shared — they stay on your device, and the currency button is purely cosmetic. Browse more number tools on the all tools page.