Kids Shoe Size by Age Calculator
Estimate children's US shoe size from age and foot length in centimetres. A handy guide for buying kids' shoes online.
How to use this tool
- Measure your child's foot from heel to longest toe on a flat surface.
- Enter the foot length in centimetres.
- Read the recommended US and EU shoe sizes.
- Always go half a size up if between sizes — kids' feet grow fast.
Quickly estimate children's US and EU shoe sizes from their foot length for worry-free online shopping.
⚠ This tool provides general estimates for education only and is not financial, tax or legal advice. Figures may not reflect your situation — verify with a qualified professional.
Formula
US kids size = round( (foot_length_inches − 3.25) × 3 × 2 ) ÷ 2
where foot_length_inches = foot_length_cm ÷ 2.54
EU size = round( foot_length_cm ÷ 0.667 )
How it works
This calculator estimates a child's US and EU shoe size from foot length in centimetres. The US formula converts centimetres to inches, subtracts a baseline offset of 3.25 inches, and multiplies by 3 to approximate the US kids' size scale; rounding to the nearest half-size is achieved by multiplying by 2, rounding, then dividing by 2. The EU size uses a standard last-unit conversion (1 Paris point ≈ 0.667 cm). Results are estimates — children's feet grow quickly and widths vary, so fitting in person remains advisable.
Worked example
- Foot length = 18 cm
- Convert to inches: 18 ÷ 2.54 ≈ 7.087 inches
- US size = round( (7.087 − 3.25) × 3 × 2 ) ÷ 2 = round(23.02) ÷ 2 = 23 ÷ 2 = 11.5
- EU size = round( 18 ÷ 0.667 ) = round(26.99) = 27
US kids size: 11.5 | EU size: 27
Common mistakes to avoid
- Using age as the primary sizing input without measuring foot length — children of the same age can differ by 2-3 shoe sizes depending on individual growth rate.
- Measuring foot length with socks on — add 0.5-1 cm for sock thickness, or measure barefoot and then account for it.
- Not allowing 1-1.5 cm of growing room — a shoe that fits snugly today will be too small within weeks for fast-growing toddlers.
Key terms
- Paris point
- The unit underlying EU shoe sizes; one Paris point equals approximately 0.667 cm (2/3 of a centimetre).
- US kids shoe size
- A sizing scale used in the United States for children's footwear, running roughly from size 0 (newborn) up to size 13.5 before transitioning to adult sizing.
- EU shoe size
- European shoe sizing based on Paris points; a foot length of 18 cm corresponds approximately to EU size 27.
- Half-size increment
- US children's shoes are commonly available in half-size steps, representing approximately 0.33 cm (one-sixth inch) of length difference.
Frequently asked questions
- How do I measure my child's foot?
- Have your child stand on paper, mark the heel and longest toe, then measure the distance. Measure both feet and use the longer one.
- Are kids shoe sizes the same worldwide?
- No. US, UK, and EU sizes all use different scales. This calculator gives US and EU sizes from foot length in centimetres.