Sales tax is a percentage added to the price of goods or services at checkout

When you buy something in a store or online, the final price you pay includes the item's listed price plus sales tax. Sales tax is a percentage of that price set by your state, county, or city. The tax gets collected by the seller and sent to the government. You calculate it by multiplying the item price by the tax rate, then adding that amount to the original price.

The tax rate varies by location. Some states have no sales tax at all. Others charge between 4 and 10 percent, and some cities add an extra local tax on top of the state rate. The rate also depends on what you're buying — groceries are often taxed differently than clothing or electronics.

Key Takeaways

  • Sales tax is calculated by multiplying the item price by the tax rate as a decimal, then adding that amount to the original price.
  • Tax rates vary by state and sometimes by county or city, so the same item costs different amounts in different locations.
  • Some items like unprepared food are exempt from sales tax in many states, while prepared food and most goods are taxed.
  • Online purchases are now subject to sales tax in most states, even if the seller is located elsewhere.
  • You can find your local sales tax rate on your state's Department of Revenue website or by asking a cashier.

The basic formula for calculating sales tax

The math is straightforward. Take the price of the item, convert the tax rate to a decimal, multiply them together, and add the result to the original price.

Here's the formula: Item Price × Tax Rate (as decimal) = Sales Tax Amount, then Item Price + Sales Tax Amount = Total Price.

Example: You buy a shirt for $40 in a state with a 7 percent sales tax. Convert 7 percent to 0.07. Multiply: $40 × 0.07 = $2.80. Add that to the original price: $40 + $2.80 = $42.80. That's what you pay at checkout.

If you're buying multiple items, add up all the prices first, then explore the tax rate to the total. A $40 shirt and a $30 pair of pants = $70 subtotal. At 7 percent tax: $70 × 0.07 = $4.90 in tax. Total: $74.90.

Finding your local sales tax rate

Your state's Department of Revenue website lists the state sales tax rate. Search "[your state] sales tax rate" to find it quickly. The rate is usually between 4 and 10 percent, though some states have no sales tax at all.

Many cities and counties add their own local tax on top of the state rate. For example, your state might charge 6 percent, but your city adds another 1 percent, making your total rate 7 percent. To find the combined rate for your specific location, call your city or county tax assessor's office, or check your city's official website.

Retailers are required to display the tax rate at checkout, either on the receipt or on a sign near the register. If you're unsure, ask the cashier — they can tell you the exact rate for your area.

Items that are usually taxed and items that are not

Most states tax clothing, electronics, household goods, and prepared food. However, many states exempt unprepared groceries — items like raw vegetables, meat, bread, and milk that you cook at home. The logic is that groceries are necessities, while prepared food (like restaurant meals or deli sandwiches) is a service and gets taxed.

Prescription medications are exempt from sales tax in all states. Over-the-counter medicines vary by state — some tax them, others don't. Medical equipment like wheelchairs or hearing aids may be exempt depending on where you live.

Services are usually not taxed, though this varies. A haircut, car repair, or plumbing job typically isn't subject to sales tax, but some states tax certain services. The best way to know is to ask the business or check your state's Department of Revenue website for a list of taxable and non-taxable items.

How sales tax works for online purchases

Online retailers are now required to collect and send sales tax in most states, even if the company is located elsewhere. This means when you order something online and have it shipped to your address, you pay the sales tax rate for your location, just as you would in a physical store.

The tax is usually calculated and added to your total before you complete the purchase. You'll see it listed separately on your receipt or invoice. If a retailer fails to collect sales tax when they're required to, you may be responsible for paying it to your state — though this is rare and most states don't enforce it for individual purchases.

Some states have different rules for digital goods like e-books, software, or streaming services. A few states tax them; most don't. Check your state's rules if you're buying digital items.

Using a sales tax calculator

If you don't want to do the math by hand, many online sales tax calculators let you enter the item price and your location, and they calculate the total for you. Your state's Department of Revenue website often has one built in. Retailers like Amazon also show the tax amount before you check out.

A calculator is useful when you're buying multiple items or comparing prices across states. It removes the chance of making an arithmetic error and shows you exactly what you'll pay.

Why sales tax rates differ by location

States set their own sales tax rates based on their budget needs. States with no income tax, like Florida and Texas, often rely more heavily on sales tax to fund schools and services. States with income tax may have lower sales tax rates.

Cities and counties add local taxes to fund schools, public transit, or local services. This is why the same item costs different amounts in different parts of the same state. A purchase in one county might have a 6 percent rate, while a purchase 20 miles away in another county has a 7.5 percent rate.

Frequently Asked Questions

Do I pay sales tax on everything I buy?

No. Unprepared groceries, prescription medications, and some services are exempt in most states. Clothing, electronics, and prepared food are usually taxed. The rules vary by state, so check your state's Department of Revenue website for a full list of what's taxed in your area.

What if the tax rate changes after I buy something?

Sales tax rates can change, but they don't affect purchases you've already made. You pay the rate that was in effect on the date of your purchase. If a rate increases next month, items you bought this month are not retroactively taxed at the new rate.

Can I get sales tax refunded if I return an item?

Yes. When you return an item for a refund, the store refunds both the item price and the sales tax you paid. If you exchange the item for something else, the tax is recalculated based on the new item's price.

Do I owe sales tax on items I buy out of state and bring home?

Technically, many states require you to pay "use tax" on items you buy out of state and use at home, at the same rate as sales tax. However, this is rarely enforced for individual purchases. It's mainly enforced for businesses buying inventory out of state.

How do I know if an online seller is charging me the right sales tax?

Check your receipt against your state's sales tax rate. The tax shown should match your location's combined state and local rate. If it doesn't, contact the seller. Most major retailers calculate tax correctly, but errors can happen with smaller online businesses.