What Size Running Shoes Should You Get?

Short answer: your running shoe size starts from your foot length and your US size, not the number on your everyday shoes. Measure in the evening, check whether the brand’s cm column is foot length or the label size, and keep about a thumb’s width of room in front of your longest toe.

The trap: one foot, four different EU sizes

The same US size gets a different EU number depending on the brand. A men’s US 9, 27 cm on the label (Japanese size), becomes:

The US size is the common reference. That is why you should compare in US sizes, never in EU sizes.

The trap: the “cm” on size charts

The cm figure on a size chart does not always mean the same thing:

•             Foot length. Nike, adidas, Hoka and Salomon publish the bare-foot length for each size. For a men’s US 9: about 10 5/16 in (26.2 cm) at Nike, 10.4 in (26.3 cm) at adidas, 10.4 in (26.4 cm) at Hoka, 10.4 in (26.5 cm) at Salomon.

•             Label cm. Asics, On, Saucony and Brooks list the Japanese size printed on the tongue: 27 cm for a men’s US 9.

Your measured foot is shorter than the label cm. On the Nike and adidas charts, which give both numbers, the gap is about 0.7 to 0.8 cm (roughly 0.3 in) for a men’s US 9. Other brands do not publish that gap. If you read your foot measurement into a label column, you risk buying a size too small. Brand guide: Hoka.

Switching brands? The StrideMatch size converter does the math for you.

Measure your foot in 2 minutes

1.          Do it in the evening: your feet have swollen, like at the end of a long run.

2.          Stand with running socks on, heel against a wall, foot on a sheet of paper.

3.          Mark the tip of your longest toe (not always the big toe).

4.          Measure from the wall to the mark. Do both feet and keep the longer one.

5.          Also measure the width at the widest point of the forefoot.

Then compare that number to the foot length column when the brand publishes one. If it does not, start from the US size of your current running shoe.

How much toe room?

Leave about a thumb’s width between your longest toe and the end of the shoe, laced and standing. Less, and your toenail hits the front on downhills. Much more, and your foot slides, which causes heel blisters.

When to go half a size up

•             You fall between two sizes on the chart.

•             You are training for a marathon or a long trail race: feet swell over the hours.

•             The model is known to fit snug (see our brand guides).

•             Your foot is high-volume (high instep) and the model has no wide version.

Wide feet: width first, length second

If your foot spills over the insole, the answer is a wide version, not a longer shoe. A shoe that is too long moves the flex point and lets your foot slide.

Signs your size is wrong

FAQ

Should running shoes be a size bigger? Not a full size. The right size leaves a thumb’s width of room, which is often half a size above your everyday shoes.

Does my size change from one brand to another? In EU sizes, yes. In US sizes, barely, so compare on those. In inches or cm, first check whether the chart lists foot length or the label size.

Do running shoes need breaking in? No. They should feel comfortable from the first try.

Same size for road and trail? Often yes, but downhills need a locked-in heel and enough toe room: test them before a long race.

Found your size? Now find your model. Take the free StrideMatch test to get the shoes that match your stride and your training.