How to Calculate Sales Tax: Formula, Examples and Rates

Quick answer: To calculate sales tax, convert the rate to a decimal and multiply it by the taxable price: sales tax = price x rate. At 8.25%, a $200 sale has $200 x 0.0825 = $16.50 tax, for a $216.50 total. For the total in one step, multiply by 1 plus the rate. To remove tax from a total, divide by 1 plus the rate.

Knowing how to calculate sales tax correctly matters every time you invoice. Undercharge and you pay the difference yourself; overcharge and you owe it to the state and risk annoying customers. This guide covers the basic sales tax formula, combined state and local rates, discounts, shipping, rounding and reverse calculation, with worked examples. Our free invoice generator applies the rate for you, and the sales tax calculator is there for quick checks.

Important: This is general information, not tax advice. Sales tax rates and taxability rules are set by each state and locality and change during the year; confirm current rates with your state tax agency.

The sales tax formula

There are three formulas worth memorizing:

• Sales tax amount = taxable price x tax rate
• Total price = taxable price x (1 + tax rate)
• Pre-tax price from a total = total / (1 + tax rate)

The rate must be a decimal. Divide the percentage by 100: 6% is 0.06, 7.25% is 0.0725 and 8.875% is 0.08875. A common error is multiplying by 8.25 instead of 0.0825, which gives an answer 100 times too large.

Quick reference table

Here is the tax on common amounts at a range of rates, rounded to the nearest cent:

Rate	On $100	On $250	On $1,000
5%	$5.00	$12.50	$50.00
6.25%	$6.25	$15.63	$62.50
7.25%	$7.25	$18.13	$72.50
8.25%	$8.25	$20.63	$82.50
10%	$10.00	$25.00	$100.00

How to calculate sales tax step by step

1. Confirm you must collect. You collect sales tax only in states where you have sales tax nexus and are registered. A handful of states have no statewide sales tax, though some local areas in those states may still levy one.
2. Decide which items are taxable. Most tangible goods are taxable; services, food, clothing and digital goods vary by state. Sales to resellers with a valid resale certificate or exempt buyers are not taxed.
3. Find the right location. For shipped goods most states use the customer's delivery address (destination sourcing); a few use the seller's location for in-state sales.
4. Look up the combined rate for that address: state plus county, city and special district rates.
5. Apply discounts first, then calculate tax on the reduced taxable amount.
6. Treat shipping per your state's rule, shown on its own line.
7. Multiply the taxable subtotal by the combined rate and round to the nearest cent.
8. Show tax as a separate line on the invoice, with the rate used.

Combined rates: state, county, city and district

The rate you charge is rarely just the state rate. Local governments add their own taxes, and the total can vary from one street to the next. Two examples from official sources, as of 2026:

• Texas: the state rate is 6.25%, and cities, counties, special purpose districts and transit authorities can add up to 2% combined, for a maximum of 8.25%, according to the Texas Comptroller local sales tax FAQ.
• California: the statewide base rate is 7.25% (6% state, 1% local and 0.25% county transportation fund), and voter-approved district taxes can push the total higher, according to the CDTFA sales and use tax rates page.

Always add the layers into one combined rate before multiplying. If a California address has a 1.00% district tax on top of the 7.25% base, the combined rate is 8.25% and the tax on $1,000 is $82.50. Calculating $72.50 and $10.00 separately gives the same answer here, but rounding each layer separately on odd amounts can create one-cent errors.

Rates change, often on January 1, April 1, July 1 or October 1, so use your state's official rate lookup by address rather than a list saved months ago.

Worked example: a full invoice with discount and shipping

A small business in Texas sells to a customer at a delivery address with an 8.25% combined rate. The invoice includes products, a discount, an installation service and shipping. For this example, assume the installation service and the separately stated shipping are not taxable under the applicable rules; check your own state.

Line	Calculation	Amount	Taxable?
Product A	4 x $45.00	$180.00	Yes
Product B	2 x $120.00	$240.00	Yes
10% discount on products	($180 + $240) x 10%	-$42.00	Reduces taxable amount
Installation service	Flat fee	$150.00	No (assumed)
Shipping, separately stated	Flat fee	$20.00	No (assumed)
Taxable subtotal	$420.00 - $42.00	$378.00
Sales tax	$378.00 x 0.0825 = $31.185	$31.19
Invoice total	$378.00 + $150.00 + $20.00 + $31.19	$579.19

Notice three things. The discount came off before tax, which is how most states treat a seller's own discount; our guide to showing a discount on an invoice explains the layout. Tax was calculated on the taxable subtotal only, not the whole invoice. And $31.185 rounded up to $31.19 because the third decimal was 5.

If the same invoice had been fully taxable, tax would be ($378 + $150 + $20) x 0.0825 = $548 x 0.0825 = $45.21, and the total $593.21. Getting taxability wrong on two lines changes the bill by $14.02.

How to calculate sales tax backwards

Sometimes you know the total and need the tax, for example from a receipt for your records or when a client agrees a tax-inclusive price. Divide by 1 plus the rate:

• Total paid: $54.13 at 8.25%
• Pre-tax price: $54.13 / 1.0825 = $50.00
• Sales tax: $54.13 - $50.00 = $4.13

Check it forward: $50.00 x 0.0825 = $4.125, which rounds to $4.13. The mistake to avoid is taking 8.25% of $54.13 ($4.47), which overstates the tax because it applies the rate to an amount that already includes tax. Our full guide to reverse sales tax calculation has more examples.

Origin vs destination sourcing

Which address's rate you use depends on how the state sources sales. This decision often matters more than the arithmetic, because two addresses a few miles apart can carry different combined rates.

Sale type	Usual rate to charge	Example
In-person sale at your shop	Rate at your shop	A walk-in customer buys a lamp at your store
Shipped order, destination-based state	Rate at the customer's delivery address	You ship a lamp to a customer across the state
Shipped order, origin-based state (in-state sellers)	Rate at your business location	Some states let in-state sellers charge their own rate
Remote sale into another state	Generally destination rate, if you have nexus there	An online order delivered to another state where you are registered
Customer picks up from your warehouse	Usually the pickup location	A contractor collects materials at your yard

If you sell online, your platform may calculate destination rates for you, but you are still responsible for registering in the right states. Large online marketplaces generally collect and remit tax on sales made through them in states with marketplace facilitator laws, which changes what you collect on your own website.

Worked example: tax-inclusive pricing for a quote

A client asks for a flat price of $1,500 "all in" for a custom product delivered to an address with a 7.25% combined rate. You need to split the price into the taxable amount and the tax so the invoice is correct:

1. Divide the agreed total by 1 plus the rate: $1,500 / 1.0725 = $1,398.60 (rounded to the cent).
2. Calculate tax on that price: $1,398.60 x 0.0725 = $101.40 (from $101.3985).
3. Check the total: $1,398.60 + $101.40 = $1,500.00.

Your invoice then shows a product line of $1,398.60, sales tax of $101.40 at 7.25% and a total of $1,500.00. Never show a tax-inclusive price as a single line with no tax shown when your state expects tax to be stated separately; it makes your sales tax return harder to reconcile and confuses customers who need to claim tax as an expense. Tracking these splits is easier if every invoice has a unique number; the invoice number generator can set up a clean sequence.

Rounding rules

Sales tax is calculated to the cent. Most states accept standard rounding, where a fraction of half a cent or more rounds up. You can usually calculate either on each line or on the invoice's taxable total, but the two can differ slightly:

Method	Three items at $1.99, 8.25%	Tax
Per line	$1.99 x 0.0825 = $0.164 (rounds to $0.16), three times	$0.48
Per invoice	$5.97 x 0.0825 = $0.4925	$0.49

A one-cent difference is not a compliance problem in itself, but you should pick one method your state permits and use it consistently.

What to do with the tax you collect

Sales tax you collect is not your income. It is money held for the state until your filing date, which may be monthly, quarterly or annually depending on your sales volume and state. A simple habit keeps you safe: each time a customer pays, move the tax portion of that payment into a separate account. When the return is due, total the taxable sales and tax from your invoices for the period, check that the tax equals the taxable sales multiplied by the rates you charged, and file. If you collected tax by mistake, most states expect you to either refund it to the customer or remit it, not keep it.

Common sales tax calculation mistakes

• Using only the state rate. Forgetting local and district rates is the most common cause of undercollection.
• Using your own rate for shipped orders in a destination-based state.
• Taxing the whole invoice when some lines, like certain services, are exempt.
• Applying tax before a discount.
• Bundling shipping into product prices, which can make shipping taxable where it otherwise would not be.
• Taxing exempt customers who have given you a sales tax exemption certificate.

Sales tax vs VAT calculations

The arithmetic is similar, but the systems differ. US sales tax is charged once, at the final sale, and is usually added on top of the shelf price. VAT is charged at every stage, with businesses reclaiming the VAT they pay, and consumer prices usually include it. If you also bill clients abroad, see the sibling guide on how to calculate VAT and our comparison of sales tax vs VAT vs GST.

Show sales tax clearly on your invoices

To calculate sales tax, find the combined rate for the location where the sale is sourced, convert it to a decimal and multiply it by the taxable subtotal after discounts. Keep exempt items and shipping on separate lines, round to the nearest cent and show the tax and rate on the invoice. To work backwards, divide the total by 1 plus the rate.

For more on presentation, read how to show sales tax on US invoices. Then create a US invoice with automatic tax lines, pick a layout like the modern invoice template, or use the free invoice generator to send your next bill today. It is free, needs no account, and exports a print-ready PDF invoice.