True-to-Size Millimeter Sizing Comparison

Allbirds Wool Runner vs Saucony Cohesion 17

Detailed size conversion chart, cavity measurements in millimeters, and crowd-sourced fit advice for choosing your perfect size.

Shoe Aunisex
Allbirds Wool Runner
4.6(3,196 reviews)
Fit TendencyTrue to Size
Width ProfileStandard (Medium)
View Full Wool Runner Breakdown
Shoe Bunisex
Saucony Cohesion 17
4.3(265 reviews)
Fit TendencyTrue to Size
Width ProfileStandard (Medium)
View Full Cohesion 17 Breakdown
Fit Verdict

True to Size Comparison

Both shoes share a very similar length profile. We recommend ordering your standard size in both.

Length Delta-0.04 mm
Width Delta-0.21 mm

Interactive Size Converter

Select what size you wear in the Wool Runner to see your calculated size in the Cohesion 17.

Recommended Size in Saucony Cohesion 17
US 8.565% Match

Internal shoe cavity difference: +3.0 mm (slightly roomier)

Alternate option if between sizes: US 8 (52% match)

Complete Size Conversion Matrix

Direct millimeter-calibrated mapping comparing all available sizes between both shoes.

Wool Runner (US)Internal CavityCohesion 17 EquivalentMatch AccuracyFit Difference
US 3.5239 mmUS 4100%-0.0 mm
US 4242 mmUS 4.553%+4.0 mm
US 4.5246 mmUS 4.5100%-0.0 mm
US 5249 mmUS 4.564%-3.0 mm
US 5.5252 mmUS 4.529%-6.0 mm
US 6256 mmUS 70%+10.0 mm
US 6.5259 mmUS 718%+7.0 mm
US 7266 mmUS 7100%-0.0 mm
US 7.5269 mmUS 7.5100%-0.0 mm
US 8272 mmUS 8100%-0.0 mm
US 8.5276 mmUS 8.565%+3.0 mm
US 9279 mmUS 8.5100%-0.0 mm
US 9.5282 mmUS 9100%-0.0 mm
US 10286 mmUS 9.5100%-0.0 mm
US 10.5289 mmUS 1065%+3.0 mm
US 11292 mmUS 10100%-0.0 mm
US 11.5296 mmUS 10.5100%-0.0 mm
US 12299 mmUS 11100%-0.0 mm
US 12.5302 mmUS 11.553%+4.0 mm
US 13306 mmUS 11.5100%-0.0 mm
US 14312 mmUS 1330%+6.0 mm

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Frequently Asked Questions

How does the Wool Runner size compare to the Cohesion 17?

Both shoes share a very similar length profile. We recommend ordering your standard size in both. The Wool Runner has an internal fit offset of -0.68mm compared to -0.72mm for the Cohesion 17.

Do these shoes fit wide feet comfortably?

The Wool Runner has a standard medium width profile, while the Cohesion 17 is snug/narrow.