How much bigger is a half size in shoes?
A half size adds 4 to 5 mm of length. In 62 brands' official men's charts, the usual step between neighbouring half sizes is 5 mm at 34 brands and about 4 mm at 20.
By Sizelane · Published 2026-11-01 · Numbers computed from the official charts on this site
The step, brand by brand
Each row is the median step between neighbouring half sizes on that brand's men's chart. Only charts with at least five half-size steps are counted. On women's charts the median across 63 brands is 5 mm. A whole size is twice the step.
| Median step | Brands | Which |
|---|---|---|
| 3.5 mm | 3 | KEEN, Lucchese, Steve Madden |
| About 4 mm | 20 | adidas, ALDO, ANTA, Ariat, BOGS, Crockett & Jones, Florsheim, Geox, Haglöfs, Hanwag, HOKA, Jordan, Karhu, LOWA, Nike, OOFOS, REEF, Sebago, Sioux, TOMS |
| 4.5 mm | 1 | Lacoste |
| 5 mm | 34 | Altra, ASICS, Asolo, Cat Footwear, Chaco, Cole Haan, Columbia, Converse, Craft, DC Shoes, Emerica, etnies, K-Swiss, Kizik, Meermin, Meindl, Merrell, Mizuno, New Balance, On, Onitsuka Tiger, PUMA, Red Wing, Reebok, Rockport, Salomon, Sam Edelman, Saucony, Sorel, Teva, UGG, Under Armour, Vans, Wolverine |
| Uneven (see below) | 4 | 361°, Blundstone, Sperry, Timberland |
Why some charts say 4 and others 5
Two habits account for most of it. Nike prints a foot length to the millimetre: 25.8, 26.2, 26.7 and 27.1 cm for US 8.5 to 10, which is steps of 4, 5 and 4 mm. New Balance moves in half centimetres: 27 to 27.5 cm for US 9 to 9.5, a step of 5 mm.
The difference adds up. From US 8 to US 12, Nike's chart gains 34 mm and New Balance's gains 40 mm, so the two scales drift apart as sizes rise. They are not two roundings of one number. The pattern is not absolute either: 3 charts with a measured foot length step 5 mm, and 6 charts with a size in cm step about 4 mm.
A half size up can add nothing on paper
4 charts list two neighbouring half sizes at the same length: 361°, Blundstone, Sperry, Timberland. 6 other charts have a step above 6 mm somewhere. On those charts, look at the two rows you are choosing between rather than the median.
If your shoes are half a size too big
You are dealing with about 4 to 5 mm. Dr. Martens is the one brand in our data with a figure for this: in our summary of its advice, leather tends to stretch in width with wear but not in length; if between sizes, go a little bigger and use an insole, which adds about half a size. Source. For the size that fits your foot instead, enter your foot length in the converter or read how much room brands say to leave.
Sources
Size data: the source register, read with the method described here.
- Nike: www.nike.com/size-fit/mens-footwear (read 2026-10-24)
- New Balance: www.newbalance.com/size-guide.html (read 2026-10-24)
- Dr. Martens: www.drmartens.com/us/en/about/size-guide (read 2026-10-24)