ASICS Shoe Size Guide

ASICS trainers are true to length: the heel-to-toe measurement of a given size lines up with the foot-length figures in the conversion chart below, so an ASICS US 9 matches a foot of the same length as any other true-to-size brand. Where ASICS differs is across the width. The brand's performance lasts are deliberately narrow through the midfoot and snug around the heel, and that close hold is the whole point — it is the trade-off that gives ASICS its renowned lockdown and keeps the foot from sliding during fast turnover. If your foot is regular-to-narrow, that means you can buy your usual length and trust it to fit straight out of the box.

Wider feet need a small adjustment. The simplest fix is to size up half, which buys a little extra room across the ball of the foot and through the toe box without changing brands — though it will not cure a genuinely narrow midfoot, only ease the pressure. The better answer, where it is offered, is the dedicated wide fitting: the 2E width for men and the D width for women, available on staples such as the GEL-Kayano, GT-2000, and Gel-Nimbus. A wide last keeps your true length while opening up the volume, so you avoid the heel slip that comes from over-sizing. As a rule, take the wide option if you have the choice and reserve the half-size-up trick for models that only come in a standard width.

ASICS is a Japanese company, and Japanese shoe sizing is refreshingly literal: the JP number is simply the length of the foot the shoe is built to fit, measured in centimetres. That is why the JP figure printed on an ASICS box doubles as a foot-length reading. A box marked JP 26.0 is cut for a 26.0 cm foot; JP 26.5 fits a 26.5 cm foot, stepping up in clean half-centimetre increments. There is no hidden offset to decode and no men's-versus-women's shift to remember — the centimetre value speaks for itself.

The practical upshot is that ASICS is one of the easiest brands to size by measurement alone. Stand on a sheet of paper, mark heel and longest toe, measure the distance in centimetres, and you have your JP size directly — round to the nearest half-centimetre and that is the number to look for on the box. Measure both feet late in the day, when they are at their largest, and size to the longer one. With your foot length in hand you can skip the chart entirely for the JP column, then read across the rows below to translate that same centimetre figure into US, UK, EU, and the other systems.

To move an ASICS size between systems, find your starting size in the charts below and read along the row — every column is anchored to the same foot length in centimetres, so the conversions stay internally consistent. Take a worked example: a women's US 8 sits on roughly a 24.1 cm foot, which reads across to a UK 6 and an EU 38. A men's US 9.5 is about a 26.0 cm foot, converting to a UK 9 and an EU 42. The men's and women's US scales are offset, so US women's sizing runs roughly one and a half sizes above the men's number for the same foot — a women's US 9.5 and a men's US 8 land on a similar length. The EU figure, by contrast, is a single unisex scale derived from Paris points, so a 39 is a 39 regardless of gender.

Use the EU and JP columns as your cross-checks when the US number looks ambiguous. The JP value is your foot length in centimetres, the EU value is the Paris-point scale, and between them they pin down the length far more reliably than the US figure alone. Bear in mind these conversions are approximate: ASICS lasts vary from model to model, and a snug GEL-Kayano will feel different from a roomier Gel-Nimbus even at the identical printed size. Treat the chart as your baseline, then apply the fit notes above — size up half or choose a wide fitting for broader feet — before you commit to a purchase.