Kids’ bike size chart

Kids’ bikes are sized by wheel, and the inseam picks the wheel. Measure once, set the slider, and you get a wheel size to start with and how high to set the seat.

Pick the wheel size

Units
inseam Inseam = inside leg. From the floor to the crotch, in socks. It’s not the inseam on a jeans label. Stand against a wall, pull a book up between the legs like a saddle, mark its top edge and measure down to the floor. Measuring a child, step by step → 20″

The inside leg: floor to crotch, in socks. Not measured yet? It takes a book and a wall.

Rider
Seat height20″First pedal bike: equal to inseamEvery rider stage
Start with14″wheels

The smallest wheel that fits, so the seat can sit at inseam height and both feet reach the ground.

Room to grow: under a year at a typical growth rate.

Also fits: 16″ and 20″. Choose a bigger wheel once your child rides confidently.

Shop your size

    Links open the shop’s own pages. No shop pays for a result.

    12″

    Inseam
    14–18″
    Height
    34–40″
    Ages
    2–3

    14″

    Start here
    Inseam
    15–20″
    Height
    37–44″
    Ages
    2–4

    16″

    Also fits
    Inseam
    16–22″
    Height
    41–48″
    Ages
    4–6

    20″

    Also fits
    Inseam
    19–25″
    Height
    45–54″
    Ages
    5–8

    24″

    Inseam
    23–28″
    Height
    49–59″
    Ages
    7–11

    26″

    Inseam
    25″ +
    Height
    56″ +
    Ages
    10 +

    Wheels drawn at their true sizes. Ranges combine REI and Two Wheeling Tots, checked 30 Oct 2026. A wheel should never be bigger than the inside leg (Cycling UK).

    Print this chart

    The kids’ bike size chart on one page, A4 or US Letter. Free to print for shops, schools and clubs.

    Download the PDF

    How high should the seat be?

    Seat height from the ground, by how confident the rider is (Two Wheeling Tots). For an inseam of 20″:

    RiderSeat compared with inseamSeat height
    Balance bike0.5–1.5″ below18.5″ to 19.5″
    Pedal bike with training wheels0–3″ above20″ to 23″
    First pedal bikeequal to inseam20″
    Experienced rider2–4″ above22″ to 24″

    How do I measure my child’s inseam?

    A girl of about six in a helmet standing beside a 16-inch children’s bike, with arrows from the floor to the wheel top, her inseam and her height
    Each arrow is measured from the floor.
    1. Child in socks, back to a wall, feet a little apart.
    2. Slide a hardback book up between their legs, spine up, as firmly as a saddle would sit.
    3. Mark the wall at the top of the book and measure from the mark to the floor.
    4. Won’t stand still? Cycling UK’s way: standing height minus sitting height. The full guide.

    Kids’ bike size questions

    What size bike for a 5-year-old?

    Usually a 16″ wheel (ages 4–6) or a 20″ (ages 5–8), by REI’s and Two Wheeling Tots’ charts. Measure the inseam to choose: children the same age vary a lot.

    Should I buy a bigger bike to grow into?

    Only as far as the inseam allows. Cycling UK says a wheel should never be bigger than the child’s inside leg, and woom advises against skipping a size. Bought at the low end of its range, a woom size lasts about two years.

    Should my child’s feet touch the ground?

    On a first pedal bike, yes: set the seat at inseam height so both feet reach the ground. Once they ride confidently, raise it 2–4″ (5–10 cm) above the inseam (Two Wheeling Tots).

    Why do two 16″ bikes fit differently?

    Their lowest seat heights can differ by several inches, and woom’s ranges start higher than other brands’ at the same wheel size. Check the model’s minimum seat height against the inseam.

    How we size: REI’s and Two Wheeling Tots’ inseam ranges, never a wheel bigger than the inside leg (Cycling UK). Sources and dates are on how we size.

    Related

    How to measure your inseam

    A book, a wall and two minutes

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