To find the right helmet size, you need your head circumference in centimetres. Here we show you how to measure correctly and how to compare the result with the size of the helmet you want. After that, you check whether the helmet fits well once it's adjusted.
In just over a minute, we show you how to measure your head with a tape measure or a piece of string. The video is in German.
In the example, the head circumference is 54 cm. For the helmet shown, that means size M with 52 to 58 cm. On other models, M often covers a different range. So always compare your measurement with the size range on the product page.
You need a flexible tape measure. Stand in front of a mirror or ask someone to help, so the tape stays level all the way round.
No tape measure to hand? Use a piece of string that doesn't stretch. Mark the point where the ends meet and measure the length with a ruler or folding rule. Write the value down.
Size M isn't the same on every helmet. The table shows the size ranges of selected KED models as listed on their product pages. You'll also see that ranges can overlap within one model.
Use the table as a guide. The size range on the product page of your chosen helmet is what counts.
Swipe sideways to see all sizes.
| Model | Use | XS | S | SM | M | L | XL |
|---|---|---|---|---|---|---|---|
| Meggy II Trend | Kids | 44-49 cm | 46-51 cm | 49-53 cm | 52-58 cm | not available | not available |
| Meggy Spark | Kids | not available | 45-50 cm | not available | 50-55 cm | not available | not available |
| POP II | Kids | not available | 48-52 cm | not available | 52-56 cm | not available | not available |
| Street Jr. Pro | Kids | not available | 49-55 cm | not available | 53-58 cm | not available | not available |
| Spiri II Trend | City | not available | not available | not available | 52-58 cm | 55-61 cm | not available |
| Pedalon* | E-bike, city | not available | 53-56 cm | not available | 56-59 cm | 59-63 cm | not available |
| REACH DT-1 | Sport | not available | not available | not available | 54-58 cm | 58-62 cm | not available |
| Crom | MTB | not available | not available | not available | 52-58 cm | 57-62 cm | 60-65 cm |
* According to the product page, the Pedalon tends to run small. If you're between sizes, KED recommends the next size up for this model.
Information as of 30 September 2026. Sizes and availability may change.
On many models, the size ranges overlap. With a head circumference of 52 cm, for example, both SM (49 to 53 cm) and M (52 to 58 cm) of the Meggy II Trend would work.
If your measurement falls into such an overlap, the larger size is usually the better choice. That's also what we show in the video. You then tighten the helmet with the adjustment system. Afterwards it has to sit centred and level, must not press anywhere and shouldn't move when you gently shake your head.
Also read the note on the product page. The Pedalon page, for example, says that it tends to run small. If you can, try on both sizes.
For children too, the measured head circumference is what counts. Age alone tells you little, because two children of the same age often need different sizes. So measure just as carefully as you would for yourself.
Buy a helmet that fits today. A helmet that is too big to grow into can shift on the head, and the adjustment system can't make up for that. Once the helmet no longer sits comfortably and securely, measure again and choose the next size.
Put the helmet on centred and level, without tilting it backwards. It should sit evenly and comfortably firm all the way round.
Does the helmet slip, press in one spot or only stay put with the adjustment system fully tightened? Then a different size or a different model will probably suit you better. If you wear a hat under your helmet in winter, check the fit with the hat on as well.
With your measurement, you'll quickly find the models that suit you in our helmet overview. Each helmet lists its sizes right on the product page.
