What Is the Right Size Kid's Bike for My Child?

Kids riding bikes
Imgorthand / Getty Images

Kids love riding bikes. As a bonus, it gets kids fit, gets them outside, offers them some independence, and most all of riding is fun. 

But kids don’t stay the same size for long. That’s why choosing the right bike for your kid, can initially seem quite confusing, but is also crucial to their being able to ride their bike safely and with confidence.

If you buy a bike that is too small your child may feel silly sitting on it, and also feel cramped. Conversely, buying a bike that is too large will be unwieldy, difficult to control, and undermine their fledgling confidence on the pedals.

Kids' Bike Sizing Chart

Use the sizing chart below to figure out how kids' bikes are measured and defined, and to know best what you're looking for when shopping for a particular bike. An important thing to know is that kids' bikes are measured using the outside diameter of the tire (diameter). This is in contrast to adult bikes, whose measurements refer to frame size.

Guide to Kid's Bike Sizes
Age Child's Height Tire Diameter (outside)
Age 2 - 5 26 - 34 inches 12 inches
Age 4 - 8 34 - 42 inches 16 inches
Age 6 - 9 42 - 48 inches 18 inches
Age 8 - 12 48 - 56 inches 20 inches
Youth 56 - 62 inches 24 inches

Go Big or Go Small?

One of the real challenges in buying a kid's bike is knowing that they will outgrow it not long after they get it. So, you're faced with a dilemma. Do you buy a good bike that will likely be too small? Or do you get a big-box clunker, a cheap and temporary solution? In that case, you're hoping that the bike doesn't fall apart or otherwise be such a poor choice that it turns your kid off to cycling altogether.

It is a question with no easy answer, but perhaps a couple different options that you can explore to help yourself out. First, do you have other kids, older or younger, that bikes can be passed through? If that's the case, it makes the question a lot easier on whether or not to spend money on a decent bike. How about extended family, cousins and the like? Are there families in the neighborhood with kids that you can maybe set up some sort of bike exchange with? 

Another option is resale. If you have connections with other cyclists who have kids, they are more likely to know and appreciate the value of a good bike. Offering it for sale, just like you would an adult's bike, is a good way to recoup some of your investment. 

Finally, certain bike shops and online retailers (including Performance Bike) offer programs for people buying kids' bikes.  The basic premise is that when you buy a kid's bike, you get either guaranteed trade-in value on the old bike when it is outgrown, and/or straight out discounts on future bikes as the kid continues to move through the bikes into the larger sizes.