Everyday Life⏱ 4 min read
How to Calculate Shoe Sizes: UK, EU, US Conversion Guide
Shoe sizing across UK, EU, and US scales is not a simple formula — it is a set of historical conventions with inconsistencies. Here is the cleanest way to convert and measure correctly.
Buying shoes online across different sizing systems is confusing because there is no single universal formula. The conversions between UK, EU, and US sizes follow historical last measurements that are close to formulaic — but not exact.
Foot Measurement Method
Most accurate approach: measure the foot, not guess the size.
1. Stand on paper with full weight on the foot
2. Mark the heel and longest toe
3. Measure the distance in mm (or cm)
4. Add 5-10mm for comfort allowance
5. Use the length to find the size
Length to size conversion (approximate):
UK size = (Foot length in cm - 1.5) / 0.667 - 23
Or use the reference table below for the foot lengths per size.
Measuring matters because sizes vary between brands by up to 1 full size.
Size Conversion Table (Adults)
UK SizeEU SizeUS Men'sFoot Length (mm)
6396.5240-245
740-417.5250-255
8428.5260-265
9439.5270-275
1044-4510.5280-285
1145-4611.5288-293
124712.5295-300
Women's Size Differences
UK women's sizes are the same numbers as UK men's,
but correspond to different foot lengths.
Women's sizing is typically 1.5 sizes smaller than men's in US:
UK 6 women = EU 39 = US Women's 8.5
Common confusion: US women's vs US men's
US Women's 8 = US Men's 6.5 = UK 6
When ordering from US sites: ALWAYS check if it is men's or women's sizing.
A women's 8 is not the same as a men's 8 -- 1.5 sizes different.
Children's Sizes
UK children's sizes start at 0 (newborn ~95mm foot)
and run to 13.5 before transitioning to adult sizing at UK 1.
Children's UK to EU:
UK 1 child = EU 17 (baby)
UK 5 child = EU 21
UK 10 child = EU 28
UK 13 child = EU 32
UK 13.5 transitions to adult: adult UK 1 = EU 33
Children's sizing changes rapidly:
Under 3 years: feet can grow a half-size every 6-8 weeks
Age 3-5: a full size every 3-4 months
Age 6-12: a full size every 4-6 months
Measure children's feet every 3 months -- never assume last year's size fits.