Everyday
Shoe Size and Foot Length Calculator
Estimate adult US, UK, and EU shoe-size starting points from foot length and a user-entered fit allowance. The calculator uses estimated size from foot length plus fit allowance using common linear sizing approximations. It returns more than one result so you can check the main answer against a useful secondary measure. Measured foot length plus allowance is only a starting point because brand lasts and width vary. There is no perfectly uniform global conversion; use the manufacturer chart and try footwear when fit matters.
Check the displayed units, assumptions, and rounding before relying on the result.
Calculate and compare
Use the number box for precision or the slider for fast scenario testing.
Scenario results
Estimated EU size
40.1
Common Paris-point approximation.
Estimated UK / US men
6.5 / 7.5
Linear adult starting-point estimates.
Length-to-width ratio
2.6
Use brand width charts for actual fit.
How the calculation works
Use consistent units and retain full precision until the final display step.
Worked example
Reproduce the displayed scenario, then change one assumption at a time.
Assumptions behind the result
- • Inputs use the units shown beside each control.
- • The displayed formula is applied without hidden market or demographic data.
- • Rounding occurs only for display; calculations keep full numeric precision.
- • Measured foot length plus allowance is only a starting point because brand lasts and width vary.
- • There is no perfectly uniform global conversion; use the manufacturer chart and try footwear when fit matters.
Mistakes that change the answer
- • Mixing percentages with decimals or mixing incompatible units.
- • Relying on a rounded intermediate value instead of the full result.
- • Changing several assumptions at once instead of testing foot length separately.