An overwhelming majority of Americans believe an attractive smile makes a person more appealing, according to a survey commissioned by the American Academy of Cosmetic Dentistry. And, respondents typically named whiter teeth as the key to a more attractive smile. The teeth-whitening industry had $11 billion in sales in 2015.

The cost of whitening your teeth depends on the products you use and whether you do it at home or at your dentist’s office.

Cost of over-the-counter products

Whitening your teeth at home using an over-the-counter product such as teeth-whitening strips or gel is the least expensive option. You can usually find whitening strips for $20 to $40 per box. A box contains enough strips to treat your teeth for a week or two.

You can also find over-the-counter trays that you fill with a whitening solution and place over your teeth. These are typically under $100.

A more expensive, but usually more effective and longer-lasting option, is to see your dentist for a custom-fitted whitening tray. A custom tray that you can use at home usually costs $400 or less.

Cost of whitening at dentist’s office

The average cost of in-office teeth whitening is $650, although it can climb to $1,000 or more, depending on the type of product used and how much your dentist charges.

In many cases, in-office teeth whitening pays off. More people say they notice a difference in the appearance of their teeth after an in-office treatment than they do with at-home treatments.

The bleaching agents a dentist uses are considerably stronger than the bleaching agents found in whitening strips or other at-home treatments. Whitening strips you buy at a store usually contain no more than 10 percent hydrogen peroxide, one of the more common bleaching agents. In-office treatments can contain between 25 and 40 percent hydrogen peroxide.

A brighter smile can be even more rewarding when you pay for your treatment with a rewards credit card.

Additional time and maintenance costs

It’s also important to consider the cost of maintaining a whiter smile. In-office whitening treatments are the fastest way to get whiter teeth. Many of those treatments take about an hour and usually only a single treatment is needed. In contrast, whitening strips need to be used for several days to two weeks before you see full results.

No teeth-whitening method offers permanent results. How long your results will last depends mostly on how you care for your teeth after whitening. Avoiding foods and drinks that stain teeth, such as coffee, tea, chocolate and red wine, will extend the results. Usually, you can expect results to last for up to a year.