Sales Tax Calculator
Add sales tax to a price, or work out how much tax is inside a price that already includes it, using the rate you enter.
Amount and tax rate
Enter the combined rate that applies to the sale (for example, state plus local). This calculator doesn't look up rates.
Sales tax
$8.25
Total with tax
$108.25
Breakdown
- Price before tax
- $100.00
- Tax rate
- 8.25%
- Sales tax
- $8.25
- Total including tax
- $108.25
Tax = price × rate, rounded to the nearest cent. Total = price + tax.
How sales tax is calculated
The OpenStax Contemporary Mathematics textbook gives the formulas, with the rate written as a decimal (8.25% = 0.0825):
When the tax comes to a fraction of a cent, the same source says to round up for half a cent or more and down for less. This calculator does the same. Your point-of-sale or invoicing system may round each line or the whole invoice, which can change the result by a cent.
Worked examples
- Adding tax: $19.99 at 7.5% gives $19.99 × 0.075 = $1.49925 of tax. That rounds up to $1.50, so the total is $21.49.
- Taking tax out: a $50.00 price that includes 20% tax is $50.00 ÷ 1.20 = $41.666…, which rounds to $41.67 before tax. The tax is $50.00 − $41.67 = $8.33.
Showing tax on an invoice
Listing the tax as its own line, with the rate, lets your customer see the price and the tax separately and makes the amounts easy to total when you report what you collected. Whether you need to collect tax at all, and at what rate, depends on the rules where the sale is taxed. For US sellers, see our guide to sales tax nexus.
Frequently Asked Questions
- How do I take sales tax out of a price that already includes it?
- Divide the tax-inclusive price by 1 plus the tax rate as a decimal to get the price before tax, then subtract that from the total to get the tax. For $108.25 at 8.25%: $108.25 ÷ 1.0825 = $100.00 before tax, and $8.25 of tax. Choose "Includes tax" in the calculator to do this.
- Which tax rate should I enter?
- Enter the full rate that applies to the sale. In the US that can be a state rate plus local rates, and it can depend on where the sale is taxed and what is being sold. The calculator doesn't look up rates, so take the rate from the tax authority where the sale is taxed.
- Do I have to charge sales tax on my invoices?
- It depends on where you sell, where your customer is and what you sell, so check with the tax authority in each place you sell into, or with a tax adviser. This calculator only does the arithmetic for the rate you enter.
- Can I use this for VAT or GST?
- The arithmetic for adding or removing a percentage tax is the same, so yes, as long as you enter the right rate. For VAT you can also use the VAT calculator.
Related: VAT calculator
Add tax to your invoices automatically
Save your tax settings in Billed once and it calculates the tax on each invoice for you.
No credit card required.