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LunaCalc

Everyday life

Shoe Size Conversion

Estimate adult or child shoe sizes from measured foot length using the captured formulas.

Calculator
mm

About this calculator

This shoe-size converter maps a measured foot length into adult or child sizes across common US, UK, EU, Mexico, Japan, and Korea scales.

Formula notes

The converter normalizes the measured length to millimetres, then applies the captured adult or child reference formulas for each regional scale.

Worked examples

  1. Example: a 254 mm adult foot length returns UK 7, US men 8, US women 9, and Japan 25.5, with a 255 mm Korea size.
  2. A 127 mm child foot length returns UK 5, US child 5.5, EU 21, and marks other adult scales as not applicable.

How to use it

  1. Choose adult or child sizing.
  2. Measure the standing foot and enter its length in mm, cm, or inches.
  3. Compare the returned sizes with the shoe manufacturer's chart.

Frequently asked questions

Should I measure with socks on?

Measure the foot the way you will wear the shoe; light socks or foot length differences are typical when fitting.

Do brands use the same formulas?

No. Regional scales are standardized references, but individual brands, lasts, and half-size conventions can differ.

Limits and interpretation

  • Foot length is only one sizing input; width, instep, age lock, and brand-specific lasts are not measured.
  • Measure both feet and follow the manufacturer or seller chart for the final size because half-size and width conventions differ.