Last Updated on October 23, 2026 by Jaxon Mike
Measuring your head for a mountain bike helmet is simple and quick. You just need a flexible tape measure. Wrap it around the widest part of your head, about an inch above your eyebrows and ears. The number you get in centimeters or inches is your helmet size, ensuring a safe and snug fit.
Getting the right helmet size is your first step to mountain biking fun. A helmet that’s too loose won’t protect you. One that’s too tight can be really uncomfortable on the trail. We found that many riders overlook this simple measurement, risking their safety. Proper sizing means you’ll forget you’re even wearing it.
- Measure your head circumference.
- Use a flexible tape measure.
- Wrap it above your eyebrows and ears.
- The measurement is your helmet size.
- A snug fit is key for safety.
Let’s walk through exactly how to measure your head for that perfect helmet fit, step by step.
Getting the Right Mountain Bike Helmet Fit: A Simple Measurement Guide
You’ve picked out your new mountain bike, and now you’re ready for the trails! One of the most important pieces of gear you’ll need is a helmet. Getting the right fit isn’t just about comfort; it’s about ensuring maximum protection. A helmet that’s too big can shift around, leaving you exposed. One that’s too small? Well, that’s just going to be a headache, literally and figuratively. We’ve found that a simple head measurement is your secret weapon for a perfect fit.
Why Measuring Your Head is Non-Negotiable
Think of your helmet like a seatbelt. It needs to be snug and correctly positioned to do its job. If it’s loose, it might not stay in place during a crash. If it’s too tight, you’ll be miserable and distracted, which isn’t ideal when you’re navigating rocky terrain. Many manufacturers provide sizing charts based on head circumference. Measuring your head ensures you consult the right chart and avoid ordering a helmet that won’t work for you right out of the box. We found that many riders skip this step, leading to returns or, worse, ill-fitting helmets.
What You’ll Need for an Accurate Measurement
Grab yourself a flexible tape measure. You know, the kind you might use for sewing or crafts. If you don’t have one, a piece of string or even a shoelace will do the trick. Just make sure you have a ruler or another tape measure handy to measure the string afterward. Avoid using a metal construction tape measure; it’s too stiff and won’t give you the accurate curve of your head.
The Step-by-Step Process for Measuring Your Head
Let’s get down to business! It’s a super straightforward process. We’ve broken it down into easy steps to make sure you get it right the first time.
1. Find the Widest Part of Your Head
This is key. You want to find the largest circumference. Picture a line that circles your head. This line should run above your ears and eyebrows. Most people find the widest part is about an inch (or two centimeters) above their eyebrows and ears. Gently run your fingers around your head to feel for where it bulges out the most. This spot will give you the most accurate measurement for helmet sizing.
2. Wrap the Tape Measure Snugly
Once you’ve located that sweet spot, take your flexible tape measure and wrap it around your head. Make sure the tape is level all the way around. It should feel snug, but not uncomfortably tight. Imagine you’re giving your head a gentle hug with the tape measure. The tape should lie flat against your head, without any kinks or twists.
3. Note the Measurement
Read the measurement where the tape measure overlaps. Most helmet manufacturers use centimeters, but inches are also common. It’s a good idea to note both if your tape measure shows them. If you used string, mark where the string overlaps and then lay it flat next to a ruler to get your measurement in centimeters or inches. Don’t guess – precision is important here for a safe riding experience.
4. Repeat for Accuracy
It’s always a good idea to measure a couple of times. Sometimes our first attempt isn’t perfectly level. Measure again, following the same steps. If your measurements are significantly different, try to find a third measurement that’s in between. Consistency here helps ensure you’re getting the true circumference of your head. We found that a second or third check increases confidence in the reading.
Understanding Your Measurement and Helmet Sizing Charts
So, you’ve got your number. What now? This measurement is your golden ticket to finding the right helmet size. Now, you’ll look at the sizing charts provided by helmet brands. These charts are usually available on their websites or on the helmet packaging.
How to Read a Sizing Chart
You’ll typically see a range of head circumferences listed next to helmet sizes like Small (S), Medium (M), Large (L), and Extra Large (XL). For example, a chart might say:
| Helmet Size | Head Circumference (cm) | Head Circumference (inches) |
|---|---|---|
| Small (S) | 51-55 cm | 20-21.7 inches |
| Medium (M) | 55-59 cm | 21.7-23.2 inches |
| Large (L) | 59-63 cm | 23.2-24.8 inches |
| Extra Large (XL) | 63-67 cm | 24.8-26.4 inches |
Find where your measurement falls within these ranges. If your measurement is right on the border between two sizes, it’s often recommended to try the smaller size first. However, always check the specific brand’s recommendations, as fit can vary slightly.
When Your Measurement Falls Between Sizes
This is where things can get a little tricky, but don’t worry. If your head measures 58.5 cm, for instance, you’re right between a Medium and a Large on our example chart. What do you do? Many experts suggest that if you are between sizes, you should try the smaller size first. A helmet that’s too big is worse than one that’s a little snug initially, as it can be adjusted. However, if you can, trying on both sizes is the best bet. Sometimes, one brand’s medium fits like another’s large. It’s a bit like buying shoes!
What to Do After You Have Your Size
Once you’ve identified your likely size, the next step is trying the helmet on. This is crucial. A helmet can look like the right size on paper, but head shapes vary. Some heads are rounder, some are more oval. The helmet should feel snug all around your head, without any significant pressure points. You shouldn’t feel any pinching or pain. A good helmet will feel secure and comfortable. You want to be able to wear it for hours without discomfort.
The Snugness Test: Is It Right?
Here’s a quick test. With the helmet on and buckled, but not tightened with the adjustment system yet:
- Gently shake your head from side to side. The helmet shouldn’t wiggle or slide excessively.
- Try to roll the helmet off your head by pushing it forward from the back. It should resist moving.
Common Pitfalls to Avoid
We’ve seen people make a few common mistakes when measuring for a helmet. Being aware of these can save you time and frustration. Let’s avoid them together!
Don’t Measure Too High or Too Low
Measuring too high up on your head will give you a smaller reading. This could lead you to buy a helmet that’s too small. Measuring too low, near your forehead, might give you a false sense of security with a larger reading. Stick to that spot about an inch above your eyebrows and ears. It’s the most reliable spot for sizing.
Avoid Over-Tightening the Measurement
While you want a snug measurement, pulling the tape too tight can distort the reading. It might make your head appear smaller than it is. A gentle, snug fit is all you need for the measurement. Think “comfortable snug,” not “constricting.”
Don’t Forget About Hair
If you regularly ride with a helmet liner or have very thick hair, consider that when measuring. You might want to measure with your liner on, or account for the extra bulk. However, most helmets are designed to accommodate standard hair thickness and thin liners. We found that for most riders, measuring with dry, styled hair is perfectly fine.
Quick Checklist for Your Helmet Measurement
To wrap it all up, here’s a quick checklist to ensure you get that perfect measurement:
- Grab a flexible tape measure or string.
- Find the widest part of your head (above ears/brows).
- Wrap the tape snugly, but not too tight.
- Note the measurement in cm and/or inches.
- Double-check your measurement for accuracy.
- Compare to the helmet brand’s sizing chart.
Conclusion
You’ve now got the know-how to get that perfectly snug mountain bike helmet fit. Remember, a simple measurement with a flexible tape measure is your key to safety and comfort on the trails. By finding the widest part of your head, wrapping the tape snugly, and comparing it to sizing charts, you’re well on your way. Don’t skip this vital step!
Your next action? Grab that tape measure and get your head circumference. Then, head to your favorite online retailer or local bike shop with your measurement in hand to find the helmet that’s just right for you. Happy trails!
Frequently Asked Questions
How do I know if my helmet is too big or too small after measuring?
After measuring, compare your number to the brand’s sizing chart. If your measurement falls on the edge between two sizes, it’s usually best to try the smaller one first. A helmet that’s too big won’t stay put, while one that’s too small will cause discomfort.
Can I use a regular metal tape measure?
No, you really shouldn’t use a metal tape measure. They are too stiff and can’t accurately follow the curve of your head. A flexible tape measure, string, or even a shoelace is much better for getting a precise circumference.
What if my hair is really thick or I wear a beanie under my helmet?
If you frequently ride with a helmet liner or have very thick hair, it’s a good idea to account for that extra bulk. You can measure with your liner on, or add about half an inch to your measurement to be safe. Most helmets are designed for average hair thickness.
Does head shape matter as much as circumference?
Yes, head shape is important! While circumference gives you the correct size range, different brands and models have slightly different internal shapes. That’s why trying a helmet on after measuring is so critical to ensure there are no pressure points and it feels secure all around.
How often should I re-measure my head for a helmet?
You generally only need to re-measure if you suspect your head size has changed significantly, perhaps after a major weight change or injury. For most people, a correct measurement taken once will serve them for buying multiple helmets over the years, as long as the helmet fit is still snug and comfortable.
I am Jaxon Mike, the owner of the Rcfact website. Jaxon Mike is the father of only one child. My son Smith and me we are both RC lovers. In this blog, I will share tips on all things RC including our activities, and also share with you reviews of RC toys that I have used.
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