Baby & Kids Shoe Size Calculator
The Baby & Kids Shoe Size Calculator converts your child's foot length into EU, UK, and US shoe sizes, with a little growing room built in. Measure from the heel to the longest toe, enter the length in centimetres, and you get the recommended size in each system. Because brands fit differently, treat the result as a starting point and check each brand's chart.
Formula
EU size ≈ (foot length cm + ~1.2 cm growing room) × 1.5
- Shoe size is based on foot length plus a small allowance so toes have room to move and grow.
- EU size ≈ (foot length in cm + ~1.2 cm growing room) × 1.5; UK and US sizes are derived from the EU size.
- Input definitions: • Foot length: the distance from the heel to the longest toe, in centimetres.
- Measure both feet — they're often slightly different — and use the larger one to choose the size.
- Feet swell during the day, so measuring in the evening gives the most reliable fit.
- Check there's about a thumb's width of space at the toe when your child stands in the shoe.
Example Calculation
Inputs
- Foot length (heel to longest toe): 12 cm
A 12 cm foot maps to about EU size 20 (≈ (12 + 1.2) × 1.5), which is roughly a UK 3.5 and US 4.5. The result includes a little growing room so the shoe isn't outgrown immediately.
Frequently asked questions
How do I measure my child's foot?
Stand them on a sheet of paper, mark the heel and the longest toe, and measure the distance between the marks in centimetres.
Why add growing room?
Toes need space to move and feet grow quickly, so a small allowance prevents shoes from becoming too tight within weeks.
Why measure in the evening?
Feet swell slightly over the day, so an evening measurement reflects the largest size and avoids buying shoes that pinch later.
My child's feet are different sizes — which do I use?
Use the larger foot. A shoe that fits the bigger foot will be comfortable on the smaller one.
Do brands fit the same?
No. Sizing varies between brands and styles, so use this as a starting point and check the brand's own size chart.
How often should I re-measure?
Young children's feet grow fast — check every 6–8 weeks for babies and toddlers, and every few months for older kids.
Related calculators
Baby Clothing Size Calculator The Baby Clothing Size Calculator suggests the right clothing size for your baby from their height (length). Because EU baby sizes are based directly on height in centimetres, you enter your baby's length and get the recommended size band plus the typical age range it covers. Sizes vary by brand, so it's usually smart to size up a little. Baby Age Calculator (Weeks & Months) The Baby Age Calculator tells you exactly how old your baby is in weeks and in months. Enter your baby's date of birth and today's date, and it returns the age in weeks (plus extra days), the number of completed calendar months, and the total days lived. It's handy for tracking milestones, vaccination schedules, and age-based clothing or feeding guides.