Kids Bike Size Calculator
Find the right bike wheel size for your child based on their height.
Covers all sizes from 12-inch balance bikes to 24-inch kids bikes.
Why wheel size matters more than age
Many parents shop by age when buying a kids bike, but age alone is a poor guide. Children of the same age can differ by 20 cm or more in height, and a bike that is too large is harder to control and less safe, while one that is too small will be outgrown in months.
Height is the best measurement. Specifically, the child’s inseam (inside leg length) determines whether they can safely touch the ground when seated. A good rule of thumb: the child should be able to place both feet flat on the ground with a slight bend at the knees.
Wheel size guide by height
These are the exact bands the calculator uses, so you can check its answer against the table.
| Wheel Size | Child Height | Typical Age |
|---|---|---|
| 10–12 inch balance bike | under 90 cm (under 35 in) | 18 months–3 years |
| 12 inch | 90–100 cm (35–39 in) | 2–4 years |
| 14 inch | 100–108 cm (39–42.5 in) | 3–5 years |
| 16 inch | 108–120 cm (42.5–47 in) | 4–6 years |
| 20 inch | 120–135 cm (47–53 in) | 6–9 years |
| 24 inch | 135–148 cm (53–58 in) | 8–12 years |
| 26 inch or adult | 148 cm+ (58 in+) | 10+ years |
Real bike ranges overlap by a few centimetres, and manufacturers do not agree with each other anyway. Treat a child within about 3 cm of a boundary as fitting either size, and let the ground test decide.
Balance bikes (no pedals): These use 10–12 inch wheels and are ideal for children aged 18 months to 3 years learning to balance before transitioning to a pedal bike.
Buying tip: If your child is between two sizes, choose the smaller one. A slightly small bike is much easier to learn on and control safely. If buying for growth, choose the larger size only if they can still touch the ground.
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
SuperGlobalCalculator is independently built and maintained. See how we build and verify our calculators.