Shoe size guide: how to measure your foot

How to measure your foot

Both Nike and ASICS describe the same method: trace your foot on paper, then measure the tracing.

1. Tape a sheet of paper to a hard, flat floor. Put your heel against a wall if you can.
2. Stand on the paper with your weight even. Nike suggests your feet about shoulder-width apart.
3. Mark the back of your heel and the tip of your longest toe. Nike’s instructions mark the tip of the big toe.
4. Measure the straight line from the heel mark to the toe mark, in cm.
5. Repeat with the other foot and use the longer measurement. ASICS says one foot is generally longer than the other.

How much room to add

ASICS says to add 1 to 1.5 cm to your foot length before you read its size chart, so your foot has room to warm up and expand during a run. Nike gives no amount, but says that if your measurement falls between two sizes, size up.

A sample size chart

This is one maker’s chart, the ASICS New Zealand size guide, men’s and unisex sizes first. Its centimetre column is shoe length, not raw foot length, so use your foot length plus 1 to 1.5 cm.

Why charts disagree

Makers do not share one chart. Nike lists a US men’s 8 as EU 41, while ASICS lists it as EU 41.5. At US men’s 6.5, Nike gives UK 6 and ASICS gives UK 5.5. Nike’s chart is in foot length in inches and ASICS’s is shoe length in centimetres, so the two cannot be compared line by line.

There is an international standard, ISO 9407, called Mondopoint. It sets out a way to mark footwear size based on measurements of the foot the shoe is meant to fit. Standards body BSI notes that some makers print centimetres in place of millimetres, for example 26 instead of 260, and that this does not follow the standard.

Use the chart on the maker’s own page for the shoe you are buying, and check that its numbers mean foot length or shoe length before you compare.