What size bike helmet do I need for my child?

You want to experience the most beautiful bike adventures together, and you want to do it safely. Therefore, a good-fitting bicycle helmet is crucial. Finding the right size is important, because a helmet doesn’t offer the promised protection when it’s too big or small. Besides that, a well-fitting helmet is more comfortable, so it’s more pleasant for your child to wear it. But how do you find the right size bike helmet for your little adventurer? We'll tell you in this blog article!

What does the size of a child’s bike helmet mean?

The sizes of children’s bike helmets are based on the wearer’s head circumference. This measurement, expressed in centimeters, can be found on any helmet. For instance, if you see 44-48 cm on a helmet, this means the helmet is suitable for children with a head circumference that falls within this range.

Apart from the standard size in cm, most manufacturers use their own sizing. These sizes are often expressed in letters, and range from XXS via medium to L or even XXL. Because these sizes differ per manufacturer, it is best to rely on the head circumference in centimeters.

How to measure a child’s head circumference

The numbers tell the tale. Thus, you should measure the head circumference of your child. Use a soft and flexible tape measure to find out your child’s head circumference. Measure slightly above the ears and make sure the tape goes in a straight line over the forehead and back of the head. This is the largest part of the head and thus represents the maximum circumference. It’s best to measure several times to rule out mistakes.

Choose the right bike helmet size for your child

Once you have determined the head circumference of your baby or child, it’s very easy to find the right size. Go to the (online) store and pick the size that corresponds to your kid’s head circumference. When it falls just between sizes, go for the larger option. Children grow fast, and enjoy a larger bike helmet for longer.

For example: if your child has a head circumference of 48 cm, and you can choose between a 44-48 cm helmet and a 48-52 cm helmet, the 48-52 cm helmet is the best choice!

What bike helmet size for what age?

Just orienting and don’t have a measuring tape at hand, but still want to know what helmet size you usually need for a certain age? This might give you an idea:

 What bike helmet size for a baby from up to 9 months old?
The average head circumference of a 9-month-old baby (the age they are usually allowed in a bicycle seat) is about 45 to 47 cm. Babies aged 1 to 1.5 years have an average head circumference of 47 to 49 cm. A good baby bicycle helmet size would thus be 44 to 48 cm.

What bicycle helmet size for children from 1.5 to 4 years?
Children aged 1.5 to 2 years have an average head circumference of 49 to 51 cm. The most common circumference of children aged 2 to 4 years is 51 to 53 cm. A children’s bicycle helmet in size 48 to 52 cm is therefore an excellent choice for most children in this age group.

What size child bike helmet for a child of 5 years old
For children from about 4 years old you should probably look for a helmet with a circumference greater than 53 cm. Urban Iki extended it’s assortment with larger helmet sizes. These helmets are suitable for head circumference of 51 tot 54 cm.

How to fit a child bike helmet for your child?

Once you have chosen a certain size bike helmet for your child, it is important to fit and adjust it properly. Put the helmet straight on the head and make sure the front covers the forehead. The back of the helmet should cover the back of your little one’s head. Also make sure that there are no spaces on the side, and the helmet cannot slide back and forth. If this is all fine, you can start fine-tuning the fit. This usually works with a knob on the back (this is also the case with Urban Iki bicycle helmets). Turn the knob so that the helmet does not fall off the head, but also make sure it is not too tight. Lastly, you can fasten the chin closure. Make sure it is neither too loose, nor too tight.

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  • 06-11-2025 - Marie Rwebsite is clear and easy to usewebsite is clear and easy to use. Good help by email to choose the right product
  • 02-11-2025 - Nick AProducts look goodProducts look good, but the website was buggy as hell on my iPhone.
  • 01-11-2025 - Konstantins BThe screw of the footrests delivered…The screw of the footrests delivered with iki urban junior seat is too long and damaged frame of my bike...
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  • 17-09-2025 - Katriona Hgreat designs and great user friendly…great designs and great user friendly website
  • 09-09-2025 - Nicola BBest bike seats available to buy! Best bike seats available - they look great and super safe. Love the Sakura pink for my daughter. We are...
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  • 02-09-2025 - Sarah GI have bought products from urban iki…I have bought products from urban iki before ans would recommend. Am looking forward to using the junior bike seat...
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