Children's bike sizing guide

If you’re in the market for a kid’s bike, it's important to know the right size to buy.

To fit your child for a bike, take her with you when you go shopping and have your child straddle the bike as though she were getting on. There should be 1 to 2 inches of space (a.k.a. standover height) between your child’s crotch area and the bike’s top bar. Any less than an inch and the bike is too big for your child. Any more than two inches and the bike is too small. (See our bikes buying guide and bike safety tips for kids.)

Kids’ bikes are sold according to wheel size. In general, for the correct standover height, look for bikes with:

• 14-inch inch wheels for kids ages 4 to 6 years 
• 16-inch wheels for kids ages 5 to 8 years 
• 18- to 20-inch wheels for 7- to 10-year-olds
• 24-inch wheels are ideal for kids ages 10 and up.

But the right wheel size all depends on how tall your child is, not age, which is why test-fitting bikes in the store is the way to go.

While you’re bike shopping, consider getting a new bike helmet. (See our youth and toddler bike helmets Ratings, available to subscribers.) A helmet can reduce the risk of a bicycle-related brain injury by up to 88 percent, so buy one that fits well and make sure your child always wears it. (See our video: fitting a bike helmet for your child.)

See the full ShopSmart blog post.

Related: Toddler bicycle seats and bike trailers.