Kids’ bike size finder
Enter standing height for a wheel-size shortlist. Add inseam and the dimensions of a specific bike for extra fit checks. The result is a starting point for a test ride.
How to measure
Measure height barefoot against a wall. For inseam, have your child stand upright and hold a thin book between their legs, spine facing upward. Measure from the floor to the top edge of the book. Use centimetres and write both measurements down before shopping.
Use wheel size to shortlist
Children’s bikes are commonly described by wheel diameter, such as 16, 20 or 24 inches. The same wheel size can come on frames with different minimum saddle heights, standover heights and reaches. Use the height ranges below to choose bikes to try, then compare your measurements with the maker’s chart.
| Wheel size | Rider height |
|---|---|
| 12-inch | 78–94 cm |
| 16-inch | 84–112 cm |
| 20-inch | 108–129 cm |
| 24-inch | 125–148 cm |
| 26-inch | 145–160 cm |
Check fit on the actual bike
Ask your child to step over the frame, sit on the saddle and put a foot down confidently. New riders often feel more secure with both feet down at first. Check whether they can reach and squeeze the brake levers while keeping their hands on the grips. Let them practise starting, stopping and turning somewhere quiet and flat.
If two sizes overlap
Compare the smaller bike’s ease of handling with the larger bike’s reach and weight. A child who can comfortably ride either may have room to grow on the larger one. If they struggle to stop, mount or steer it, choose the bike they can control today.
Compare a bike’s dimensions
The calculator can compare an entered inseam with the minimum saddle height and standover height of a bike you are considering. It uses those numbers to flag questions for a test ride. Saddle width, shoes, foot position and where the maker measures standover all affect practical fit. A close numerical match needs an in-person check.
How the size finder works
Wheel-size suggestions use the broad height bands in 99 Bikes’ published children’s guide. Overlapping bands show both sizes. Inseam is used for the optional dimension checks, rather than to create a universal wheel-size formula. The tool stores no measurements and sends no form data.
Compare individual wheel sizes
Read the 16-inch guide for early pedal-bike controls and stopping, the 20-inch guide for gears and overlapping sizes, and the 24-inch guide for comparisons with youth and adult frames.
Further reading · 99 Bikes kids’ wheel-size guidance