Adidas Adizero Evo SL

For fewer than 4 in 10 feet. If you follow Adidas's size guidance online, the Adizero Evo SL fits true to size for 37% of feet. Here, true to size means the size Adidas's online guidance gives you is less than a full size away from the size that fits best, with enough toe room and enough forefoot volume.

Adidas did a good job with the length. Adidas's size chart says clearly that the measurement to compare is your foot length from heel to toe, and the inside of the Adizero Evo SL is about 10 mm longer than the foot length the chart gives for each size, so the room in front of the toes is already built in. Most brands only list a measurement for each size, so shoppers don't know whether to add extra length to their foot measurement for toe room. The guidance falls short on forefoot volume, because the Adizero Evo SL comes in one width. If Adidas offered width options with width measurements in its guide, the Adizero Evo SL might have gotten a full score of 100!

Adidas's size chart is shared across its shoes, but how well the chart works depends on the model. Here is where every foot landed in the Adizero Evo SL, in the standard width, when we followed that chart and ordered the usual size, as Adidas recommends.

Share of 16,874 feet. Each foot is counted once.

• Right size from the size chart: 37% of feet got a size that fit both their foot length and their forefoot volume in the standard width. Adidas's online size guidance worked well for this group in the Adizero Evo SL.
• Sized up for more forefoot volume: For 25% of feet, the standard width had too little forefoot volume at the size the chart gave. The Adizero Evo SL has no wide version, so going up a size was the only way to get more forefoot volume, and the bigger size also adds length in front of the toes.
• Sized up for toe room only: No feet landed here: 0 of 16,874. Adidas's size chart leaves every foot enough room in front of the toes in the Adizero Evo SL.
• Sized down for less forefoot volume: For 38% of feet, the standard width had too much forefoot volume at the size the chart gave. The Adizero Evo SL has no narrow version, so a smaller size was the only way to get less forefoot volume. Most of these feet (5,895 of 6,427) still fit inside a size smaller than Adidas's guidance gave, but with less room in front of the toes. The other 532 feet are too long for the smaller size, so the Adizero Evo SL leaves them with too much forefoot volume at either size.

We measured the standard width of the Adizero Evo SL and virtually fitted 16,874 real feet from our earlier in-store 3D foot scanners. Out of 17,311 foot scans, those 16,874 feet fall in the Adizero Evo SL's size range (US men's 4 to 15). For every foot, we followed Adidas's size guidance online: the length chart, ordering the usual size as Adidas recommends, in the standard width. A difference of a full size or more between Adidas's size and the size that fits best counts as a miss. These numbers show how the Adizero Evo SL fits a large group of feet, not how the shoe feels on a run.