Kids’ bike size chart by height and wheel size

Start with a child’s actual height and inseam, not age alone. The result suggests a wheel reference to check against the specific bike.

Editorial responsibility: Gonzalo Caballero González · Reviewed: 2026-09-18

BIKZER / Sizing guides

Find your reference bike size

Your sizing reference

Enter your measurements to check the chart.

Read our method and limitations →

01 / How to measure

Height

Stand barefoot against a wall and look straight ahead.
Place a level book on your head and mark its lower edge.
Measure from the floor to the mark. Repeat to check consistency.

02 / How to measure

Inseam

Stand barefoot against a wall with your feet slightly apart.
Hold a level book between your legs with firm, comfortable pressure.
Measure from the floor to the top edge. Do not use your trouser inseam.

Choose a bike they can control now

Age can organise a catalogue, but children of the same age have different measurements and abilities. Buying a large bike to grow into can make mounting, stopping and using the brakes harder. Check the current fit and the adjustment room allowed by the manufacturer.

What to try before buying

With the bike supported in a safe place, check that the child reaches the handlebar and brakes without stretching. Look at minimum saddle height, clearance when stepping down and the ability to start and stop with control. A learning saddle position may differ from one used for confident pedalling.

How to read the children’s chart

These references come from Trek’s children’s guide and are converted from feet and inches to centimetres. Overlaps and uncovered gaps are intentional; we do not fill gaps with invented recommendations. This tool caps the 26-inch range at 158 cm. Above it, compare the manufacturer’s youth and adult frame options.

Frequently asked questions

What wheel size matches a 110 cm child?

This height matches the 16-inch reference. Also check inseam, minimum saddle height and control on the actual model.

Can I choose by age alone?

No. Measure height and inseam and check the child’s ability to control the bike.

Why do two wheel sizes match one height?

The ranges overlap and geometry varies by model. Compare both with measurements and a test; do not choose the larger one automatically.

Sources and model checks

Reference size chart

Children’s reference based on Trek’s guide, converted to centimetres. Fit also depends on the model, brake reach and minimum saddle height. The 26″ range is capped at 158 cm in this tool.

Scroll the table sideways to see every column.

Reference size chart · Kids
Wheel	Rider height	Reference inseam
12″	91.44–99.06 cm3′ 0″–3′ 3″	38.1–45.72 cm15–18 in
16″	104.14–121.92 cm3′ 5″–4′ 0″	40.64–55.88 cm16–22 in
20″	114.3–137.16 cm3′ 9″–4′ 6″	48.26–63.5 cm19–25 in
24″	124.46–149.86 cm4′ 1″–4′ 11″	58.42–71.12 cm23–28 in
26″	142.24–158 cm4′ 8″–5′ 2.2″	≥ 63.5 cm≥ 25 in