The Ultimate Bike Helmet Size Chart For Beginners

The Ultimate Bike Helmet Size Chart For Beginners

Hey there! If you’re new to cycling, one of the first things you’ll need is a properly fitted bike helmet.

I know searching for the right size helmet can be confusing, but this guide will make it easy.

I’ll explain everything you need to know about measuring your head, reading size charts, and finding the perfect helmet for you or your kids.

Stick with me and you’ll be picking out stylish brain buckets in no time!

Bike Helmet Size Chart

Let’s start with the basics – how helmet sizes are measured.

Most brands determine sizes based on the circumference of your head.

This is typically measured in inches or centimeters just above your eyebrows and around the largest part of your head.

Here’s a handy size chart to use as a reference:

SizeHead Circumference (inches)Head Circumference (cm)Typical Age Range
XXXXXS18.11460-1 years
XXS18.5471-2 years
61948.33-4 years
6 1/819 3/849.24-5 years
6 1/419 3/450.25-6 years
6 3/820 1/851.15-7 years
6 1/220 1/252.16-10 years
6 5/820 7/8537-11 years
6 3/421 1/4548-12 years
6 7/821 5/8559-13 years
72255.910-14 years
7 1/822 3/856.811-15 years
7 1/422 3/457.812-16 years
7 3/823 1/858.712-16 years
7 1/223 1/259.713-17 years
7 5/823 7/860.614+ years
7 3/424 1/461.614+ years
7 7/824 5/862.5Adult
8 1/825 3/864.4Adult
8 1/425 3/465.4Adult

As you can see, helmet sizes generally correspond to hat sizes, but the exact fit can vary depending on the brand and model.

Most adult helmets range from small to large, covering head circumferences from around 52-62 cm or 20.5-24.4 inches.

Youth and children’s helmets start around 46 cm or 18 inches.

I’ll go into more detail on how to use this chart properly in a bit.

First, let’s go over how to measure your noggin!

How Do I Know My Bike Helmet Size?

To find your perfect helmet size, you’ll need to accurately measure the circumference of your head.

Here’s a simple step-by-step guide:

What You’ll Need

  • Flexible measuring tape
  • Helper (optional)
  • Pen and paper (optional)


  1. Remove any hair accessories, buns, or ponytails that protrude from your head.
    You want the tape to lay flat against your head.
  2. Wrap the flexible tape measure around your head about 1 inch above your eyebrows and ears.
    Make sure the tape lays flat all the way around.
  3. For the most accurate measurement, have a helper assist you.
    They can line up the tape properly and read the measurement.
  4. Record the measurement in both inches and centimeters.
    Round to the nearest eighth of an inch or half centimeter.
  5. Repeat steps 2-4 a couple times to ensure an accurate reading.
    The circumference may vary slightly but should be very close between measurements.
  6. Compare your head circumference to the size chart to find your approximate helmet size.
  7. Still not sure? You can always consult with a bike shop employee to match your measurement to brand and model options.

See, learning your helmet size isn’t so tough!

Now let’s talk about how to take the measurement of a wiggly kiddo…

How Do I Measure My Child’s Head for a Bike Helmet?

Getting an accurate measurement for a child’s head circumference requires a bit more finesse.

Kids don’t always love sitting still for head measurements.

Here are some tips to make it easier:

  • Explain what you are doing and why so they understand the process.
    Tell them it will only take a minute.
  • Make it fun by singing songs or turning it into a game.
    See who can stay still the longest.
  • Have them sit in a chair or on your lap while you measure.
    Gently hold their head to keep it steady.
  • Distract them with toys, books, or videos so they focus on something else.
  • For infants, swaddle them snug in a blanket with their head exposed to measure easily.

Move slowly and patiently.

It may take a few tries to get an accurate read.

Allow wiggle room in your schedule and don’t force it if they become upset.

Recording a couple different measurements allows room for error.

The right motivation and restraint, along with a dash of creativity, and you’ll have that measurement in no time!

What Size Helmet for a 10-Year-Old?

The average 10-year-old has a head circumference of 20-21.25 inches (51–54 cm).

According to the size chart, that puts most kids this age in the small to medium helmet range.

However, all kids grow at different rates, so always measure first.

If your 10-year-old falls outside the average range, go by their individual measurement, not their age.

Proper fit is essential.

For borderline measurements, consider sizing up to allow room for growth.

Kids’ heads grow rapidly and you don’t want them outgrowing a helmet after one season.

Leave room for thick winter headwear too.

Some kids in this age range may still fit youth helmets, which often come in fun colors and patterns they’ll love.

If in doubt, consult your local bike shop on the best options.

And don’t forget to model safe behavior by wearing your own helmet every time you ride!

What Size Helmet for a 22-inch Head?

A 22-inch (55.9 cm) head circumference falls into the large adult helmet size range.

Looking at the chart, 22 inches is on the smaller end of large.

With this measurement, you have some flexibility.

Large-size helmets from most manufacturers should fit comfortably.

You may want to try some XXL helmets too, especially brands labeled “large/XL.”

The XXL will give you a little more wiggle room in the fit.

I always recommend trying on a few options around your size measurement.

Helmet shapes and interior padding differ between brands.

A Bell helmet may fit slightly different than a Giro or Specialized, even if they are all large.

Don’t settle if a helmet doesn’t feel secure or comfortable on your 22-inch head.

A proper fit should encapsulate your head snugly without pinching.

Keep trying helmets until you find that just right feeling.

Safety and comfort are non-negotiable!

Should I Size Up or Down for Bike Helmet?

I get this question a lot since helmet sizing can be tricky.

If your head measurement falls between the cracks of two sizes, follow these tips:

Size Up If:

  • Your measurement is closer to the upper end of your base size
  • It’s for a child who will grow
  • You wear thick hair or headwear while riding
  • You prefer a looser fit

Size Down If:

  • Your measurement is closer to the lower end of your base size
  • The helmet brand runs large
  • You have a very oval head shape
  • You prefer a snugger fit

For example, if your head measures 57 cm, that puts you between a medium and a large.

I would size up to large if you ride with a thick headband.

But I would size down to medium for a child near the lower end of that range to leave room to grow.

Getting the right fit means safely maximizing the helmet’s protection.

Don’t hesitate to swap sizes during your search.

Consult staff for guidance too.

A little trial and error will lead you to the perfect match.

How Do I Know What Size Helmet to Buy?

Here are my top tips for using your head measurement to buy the perfect bike helmet:

  • Print out the size chart to take with you when shopping.
  • Try on multiple brands and models in your size. Fit varies.
  • Give it a good wiggle test – it should not shift on your head when shaking side to side or up and down.
  • Make sure straps lay flat against the cheek and jawbone. Adjust so the buckle sits just below the ear lobe.
  • Test with any headwear you’ll wear while riding – headbands, winter hats, etc.
  • For kids’ helmets, opt for adjustable sizing pads and straps to allow room to grow.
  • Don’t hesitate to size up or down if you’re between sizes.
    Go with the one that feels most secure.
  • Ask bike shop employees for recommendations based on your head shape and measurement.
    They are experts!

Take your time and don’t settle.

A helmet should fit like a glove, keeping you safe and comfortable on every ride.

Following this guide and using the tips above will set you up for success.

Final Thoughts

Finding your perfect bike helmet match doesn’t have to be a painful process.

Arm yourself with a soft measuring tape, utilize the size chart as a guide, and remember to try on a range of options around your measurement.

Consult the experts at your local bike shop and listen to your gut – you’ll know the right fit when you feel it.

A snug and secure helmet means you’re ready to ride safely and comfortably.

Here’s to many happy helmet-haired miles ahead!

Let me know if you have any other bike safety questions.

For now, get out there and start wheeling around in your new favorite headgear. Pedal on, friends!

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Joey B. Ramsey
Passionate cyclist, father, and blogger.
I've been riding bikes since childhood and enjoy sharing my knowledge with fellow cycling enthusiasts.
My diverse bike collection allows me to write reviews and advice based on personal experience with various bikes and accessories.
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