ASICS Shoe Sizing Guide: Do They Run Small?
ASICS fits true to size, and it offers genuine width options (standard D, wide 2E, and extra-wide 4E) on its key running models — so if your foot is wide, ASICS is one of the few performance brands where sizing up for width rather than length is a real option. Start with your usual US size and choose a wider grade if needed.
Across our data ASICS true to size: 10% of wearers report it runs small, 75% true to size and 15% large.
ASICS sizing philosophy
ASICS (Anima Sana In Corpore Sano — "a sound mind in a sound body") is a Japanese running brand, and its lasts reflect the Japanese tradition of precision fit: shoes are graded to a last designed for a specific foot type rather than given a single universal cut. That philosophy shows up in the width range — D, 2E and 4E are stocked on the Gel-Kayano and Gel-Nimbus lines — and in the higher-than-average confidence of the brand's fit data.
The length calibration is close to standard, making ASICS one of the more straightforward running brands to check from the usual-size starting point. The main variable is the upper: knit uppers on the Gel-Nimbus 25+ stretch slightly and feel more accommodating, while the structured mesh of older models is less forgiving at the same length.
How ASICS models differ
There is no single "ASICS size" — different lines are graded on different lasts. Here is how the key models compare:
- Gel-Kayano (stability)
- A wide-last flagship with excellent width availability (D, 2E, 4E). True to size in length; choose your width first, then your length.
- Gel-Nimbus (neutral cushion)
- Similar to the Kayano in sizing and width availability; runs true to size with a roomy toe box that suits many foot shapes.
- GT-2000 / Gel-Cumulus (daily trainer)
- Slightly narrower through the midfoot than the Kayano/Nimbus; true to size for length, but standard-width buyers may notice a snugger feel through the arch.
Practical sizing advice
If you normally wear US 9, start by checking ASICS in US 9 — and if your foot is wide, check for 2E or 4E availability before sizing up in length.
If your feet are wide
ASICS is one of the best performance brands for wide feet, offering genuine D, 2E and 4E widths on major running models. Always pick a wider grade before adjusting length — a 2E at US 9 fits very differently from a D at US 9.5, and the 2E is usually the right answer.
If you wear US 9, start by checking ASICS in US 9
This table starts from the US size you wear in a true-to-size brand, converts it to a foot length, and applies ASICS's measured fit so you can see the first size to check — plus the UK, EU and CM equivalents.
| You normally wear (US) | Foot length | Check ASICS (US) | UK | EU | CM |
|---|---|---|---|---|---|
| US 7 | 246mm | US 7 | 6 | 37 | 24.5 |
| US 8 | 254mm | US 8 | 7 | 38 | 25.5 |
| US 9 | 262mm | US 9 | 8 | 39 | 26 |
| US 10 | 271mm | US 10 | 9 | 41 | 27 |
| US 11 | 279mm | US 11 | 10 | 42 | 28 |
| US 12 | 288mm | US 12 | 11 | 43 | 29 |
EU sizes are always rounded to a whole size — there is no exact half-size equivalent. The recommended ASICS size applies this brand's average fit; individual models still vary, so check the model notes above.
Full ASICS size conversion
For the complete ASICS size chart with US, UK, EU and CM by foot length, the reported-fit distribution and our sources, visit the ASICS brand hub.
ASICS size guide & converter →
ASICS offers wider widths (2E, 4E) — see the brand hub for the full width breakdown.