Know Your Head First
Helmet Fit: Round vs Oval
Measure first, then match your head shape to the helmet shape for a riding helmet that sits level and snug.
Wrap a tape around your head one inch above your eyebrows to get your size, then check whether your head is round or long oval. Match both to the helmet, and try the next size if you land between two.
How to measure your head for a riding helmet size
Measure your head with a soft tape one inch above your eyebrows, around the widest part at the back, and compare that number to the chart for the helmet you want. Read it in centimeters or inches and measure twice. For more detail, see our guide on how to measure your head for a riding helmet, and use the 2-2-2 rule to check the fit once the helmet is on.
- Use a soft cloth or paper tape measure, not a metal one.
- Wrap the tape around your head about one inch (2.5 cm) above your eyebrows.
- Run it over the widest part at the back of your head and keep it level all the way around.
- Read the number in centimeters or inches and measure a second time to confirm.
- Find that number on the chart for the maker you are shopping and note which size it falls in.
Round vs oval head shape: which riding helmet fits
Round heads measure about the same front to back as side to side, while long oval heads run longer front to back than ear to ear, and the helmet shape should follow yours. One K builds two shells for this, Regular/Round and Long Oval, both in every size, and Troxel states that the Spirit's inside shape fits round to long oval heads. Our guide to round or oval heads and which helmet fits goes further. Padding and adjustment change how a shell feels on your head, and the rider words below show it.
I have a very round head (I cannot wear Charles Owen, at all) and even the “long oval” OneK fits me, probably because it has a lot of padding.
I’m a long oval and my favorites are GPAs (yes, the older models were very round, but I haven’t found that to be the case with my last several models), Samshields, and (drum roll) the Ovation dial-to-fit helmets (these are actually my favorites despite having several of the other two brands).
Riding helmet size charts by brand and head circumference
Find your measurement from the first section in the charts below, then read across to the size on the same row. Each chart prints its own notes and is a guide only, because head shape can change which size works. Choose the row your number lands in, not the one nearest your usual hat size.
| EU Size | US Size | Helmet Size | (A) Head Circumference |
|---|---|---|---|
| 54-55 | SMALL | 6 5/8- 6 3/4 | 20.5" - 21" |
| 56-57 | MEDIUM | 6 7/8- 7 | 21.5"-22" |
| 58-59 | LARGE | 7 1/8- 7 1/4 | 22.5"-23" |
| 60-61 | XLARGE | 7 3/8- 7 1/2 | 23.5"-24" |
- All measurements in the table are body measurements, not actual helmet measurementsUse a measuring tape to measure your head circumference. The tape should sit just above the ears and wrap around the center of the forehead and the back of your skull. The EU helmet size equals the head circumference in centimeters. The helmet should sit as low as possible, and be a snug fit, so that it doesn't move when you shake your head around.
| SIZE | INCHES | CM | HAT SIZE |
|---|---|---|---|
| XS | 19 5/8" - 20 3/8" | 50-52 | 6 1/4 - 6 1/2 |
| S | 20 3/4" - 22" | 53-56 | 6 5/8 - 7 |
| M | 22" - 22 3/4" | 56-58 | 7 - 7 1/4 |
| L | 22 3/4" - 23 1/8" | 58-59 | 7 1/4 - 7 3/8 |
| XL | 23 1/8" - 24 3/8" | 59-62 | 7 3/8 - 7 3/4 |
- This size chart is a guide only. Head shapes can be unique, changing what size is needed.
| SIZE | cm | US Hat size |
|---|---|---|
| XX Small - Small | 52 - 55cm | 6 1/2 - 6 7/8 |
| Small - Medium | 55 - 57cm | 6 7/8 - 7 1/8 |
| Medium - Large | 57 - 59cm | 7 1/8 - 7 3/8 |
| Large - X Large | 59 - 61cm | 7 3/8 - 7 5/8 |
| Size | Centimeters | Inches |
|---|---|---|
| XS/S | 51 - 54 cm | 6 3/8 - 6 3/4 |
| S/M | 54 - 57 cm | 6 3/4 - 7 1/8 |
| M/L | 57 - 58 cm | 7 1/8 - 7 1/4 |
| LG/XLG | 58 - 61 CM | 7 1/4 -7 5/8 |
| Size | Centimeters | Inches |
|---|---|---|
| XS/S | 51 - 54 cm | 6 3/8 - 6 3/4 |
| S/M | 54 - 57 cm | 6 3/4 - 7 1/8 |
| M/L | 57 - 58 cm | 7 1/8 - 7 1/4 |
| LG/XLG | 58 - 61 CM | 7 1/4 -7 5/8 |
| Size | Centimeters | Hat Size |
|---|---|---|
| XS/S | 51cm - 54cm | 6 3/8 - 6 3/4 |
| S/M | 54cm - 57cm | 6 3/4 - 7 1/8 |
| M/L | 57cm - 58cm | 7 1/8 - 7 1/4 |
| L/XL | 58cm - 61cm | 7 1/4 - 7 5/8 |
Between helmet sizes: how to check the fit at home
If you fall between two sizes, try both and keep the one that sits snug all around with no rocking front to back or side to side. The brim should sit about two fingers above your eyebrows, as the 2-2-2 rule describes. Makers offer ways to fine-tune, from dial-fit systems to refit liners, and the table below shows the liner options from the makers we carry.
| Maker | Liner detail | Carried |
|---|---|---|
| One K | CCS MIPS Refit Liner and CCS MIPS JR Refit Liner | |
| IRH | IR4G XLT helmets come with two machine-washable liners in two thicknesses; replacement liners come as 8 different liners in 4 thicknesses | IR4G and XLT Helmet Replacement Liner |
| TuffRider | The Coolmax liner is sold on its own and is machine washable. | Washable Coolmax Helmet Liner |
| Ovation | The Deluxe Schooler has a removable lining. | Deluxe Schooler Helmet |
Riding helmet size ranges for adults, kids and small heads
Kids and small heads start at sizes as small as XS, and the table below lists the smallest size and head range for several makers. Troxel's kids guide says to measure the child's head one inch above the eyebrows and buy a helmet that fits now, not one to grow into, and notes that dial-fit systems adjust as heads grow. Our page on how a child's helmet should fit covers it step by step.
| Model | Smallest size | Head range as listed | Adjuster |
|---|---|---|---|
| Ovation Deluxe Schooler | XXS/XS | Dial | |
| Equinavia Skylar | XS/SM | Dial | |
| TuffRider Ultimate Wide Brim | Small | Adjustable dial fit system | |
| Shires Karben Sonic Alessa | X Small | 49 to 51 cm | See the product page |
| IRH Equi-Pro | X Small | Hat size 6 1/8 to 6 3/8 | See the product page |
| Trauma Void Lynx Smooth | Small | 50 to 53 cm | Dial-fit system |
| Troxel Sport 2.0 | X Small | Hat size 6 1/4 to 6 1/2 | See the product page |
| One K Junior (Defender Jr) | X Small | Swappable liners |
What riders say about helmet fit and head shape
Fits great, is comfortable and a great price. I have a rounder oval shaped head, as opposed to a long oval. I'm on the line between a med and lg, even with non adjustable helmets I'm always in-between two sizes and needed a shim. This helmet was supposed to fit a slightly more round head shape, and it was suggested to size up to Lg if in-between. And it fits perfect, so happy I got the right helmet on the 1st try! I don't need a shim, the adjustment dial doesn't get caught in my hair. It looks good, I get a lot of compliments.
I CANNOT fit in a CO. I tried both Samshield and One K (was prepared to buy whatever fit better), and it was the One K.
On a two-hour ride I had no issues with the headgear whether going up or down hills. I love this helmet, by the end of the ride I felt like I was wearing a baseball cap with a chinstrap.
Very pretty and elegant for training. I bought a Large and it fit perfect! I use a size 7 3/4 and I was happy the helmet had a tightening dial to make it fit snug and comfortable. I love the adjustment option because I can wear my hair up, down or in braids and I can adjust to size. Definitely buying this item again in the future.
Shop riding helmets by head shape and size
Shop Riding Helmets
Shop all ›Once you have your measurement and head shape, filter the helmets below by size to see the ones that cover your head circumference. Check the maker's chart on the product page, and try two sizes if you sit between them.
Riding Helmet Fit FAQ
How do I measure my head for a riding helmet?
Wrap a soft tape measure around your head one inch above your eyebrows, over the widest part at the back, and keep it level. Read the number in centimeters or inches, then match it to the size chart for the helmet you want. Measure twice, then pick your size from the chart.
CloseHow do I know if I have a round or oval head?
A round head measures about the same front to back as side to side, while a long oval head is longer front to back than ear to ear. Check by comparing those two measurements. Then look for a helmet built for your shape, such as One K's Regular/Round or Long Oval shells.
CloseWhat if I am between riding helmet sizes?
Try both sizes and keep the one that sits snug all around with no rocking in any direction. Dial-fit systems and sized refit liners from the maker can fine-tune the fit. If the larger size still moves, go down a size. Measure again before you decide.
CloseHow should a riding helmet fit?
A riding helmet should sit level and snug all around, with no rocking front to back or side to side. The brim sits about two fingers above your eyebrows. If it moves, try another size or a different shape, and check the 2-2-2 rule page for the full test.
CloseHow should a child's riding helmet fit?
Measure the child's head one inch above the eyebrows and buy a helmet that fits now, not one to grow into, as Troxel's kids guide advises. A dial-fit system can adjust as the head grows. Check the size chart for kids' sizes before you order.
Close