How Should a Bike Helmet Fit
No matter your age, biking outdoors is a great way to stay active, view nature’s scenery, and enjoy fresh air. With any outdoor adventure, it’s always important to think about safety first. Aside from keeping up with routine bike maintenance for safety, it’s also important to wear a properly fitted bike helmet. Whether you’re looking to purchase a new bike helmet for your child or yourself, we’ll walk you through how to measure for a bike helmet and how your bike helmet should fit.
How to Measure Head for Bike Helmet
Wearing a bike helmet that properly fits is important in order to offer maximum head protection upon impact. Since most bike helmets are sized by head circumference, you’ll want to use the basic steps below to get an accurate measurement.
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Grab a flexible tape measure or a piece of string
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Wrap around the largest part of your head (about one inch above the eyebrows)
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Check to make sure the tape measure is even
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Take note of the measurement in both inches and centimeters. This is your head circumference.
Now that you know your head circumference, you can use this information to find the right size bike helmet. Below are a few bike helmet size charts to use to get an idea of what bike helmet size would work best. Please note that bike helmet sizes are slightly different depending on the brand, so pay attention to the circumference and sizing information related to the bike helmet’s brand if available.
A bike helmet size that’s marked as “one size fits most” or “universal sizing” will have a highly-adjustable sizing system for a wide range of head sizes.
Kids’ Bike Helmet Size Chart
| Age (years) | Circumference (in.) | Circumference (cm) |
|---|---|---|
| Infant (1—2) | 18.7—19.7 | 46—50 |
| Toddler (2—5) | 18.9—20.5 | 48—52 |
| Kids (5—8) | 19.7—21.3 | 50—54 |
| Kids (8—14) | 21.2—22.8 | 54—58 |
Adult Bike Helmet Size Chart
| Size | Circumference (in.) | Circumference (cm) |
|---|---|---|
| S | 20.1—22.4 | 51—57 |
| S/M | 20.1—22.8 | 51—58 |
| M | 21.25—23.6 | 54—60 |
| M/L | 21.7—24 | 55—61 |
| L | 22.8—24.8 | 58—63 |
| XL | 23.6—26 | 60—66 |
| Universal Sizing (one size fits most) | 21.25—24 | 54—61 |
If you’re between helmet sizes, start by sizing up and making the necessary adjustments. It’s important to push the helmet side-to-side and front-to-back. If you notice your helmet moving more than an inch in any direction, try the next size smaller.
How to Fit a Bike Helmet
When to Replace Your Bike Helmet
Many people wonder how often they should replace their bike helmet. If you are in an accident, you’ll want to replace your bike helmet right away. Even if you don’t see any exterior damage, once your bike helmet has absorbed impact from a fall, the plastic shell and helmet liner won’t offer the right protection against a second fall. Otherwise, if your helmet hasn’t absorbed impact, you’ll want to replace your bike helmet after five years. If you don’t remember the last time you purchased a new bike helmet, it’s a good idea to buy a new one!
