True-to-Size Millimeter Sizing Comparison

Allbirds Tree Runner vs On Cloud 6

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

Shoe Aunisex
Allbirds Tree Runner
4.7(6,450 reviews)
Fit TendencyTrue to Size
Width ProfileStandard (Medium)
View Full Tree Runner Breakdown
Shoe Bwomen
On Cloud 6
4.0(377 reviews)
Fit TendencyTrue to Size
Width ProfileStandard (Medium)
View Full Cloud 6 Breakdown
Fit Verdict

True to Size Comparison

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

Length Delta0 mm
Width DeltaIdentical

Interactive Size Converter

Select what size you wear in the Tree Runner to see your calculated size in the Cloud 6.

Recommended Size in On Cloud 6
US 10.5100% Match

Internal shoe cavity difference: 0.0 mm (snugger)

Complete Size Conversion Matrix

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

Tree Runner (US)Internal CavityCloud 6 EquivalentMatch AccuracyFit Difference
US 3.5240 mmUS 5.5100%0.0 mm
US 4243 mmUS 6100%0.0 mm
US 4.5247 mmUS 6.5100%0.0 mm
US 5250 mmUS 7100%0.0 mm
US 5.5253 mmUS 7.5100%0.0 mm
US 6257 mmUS 8100%0.0 mm
US 6.5260 mmUS 8.5100%0.0 mm
US 7267 mmUS 9100%0.0 mm
US 7.5270 mmUS 9.5100%0.0 mm
US 8273 mmUS 10100%0.0 mm
US 8.5277 mmUS 10.5100%0.0 mm
US 9280 mmUS 11100%0.0 mm
US 9.5283 mmUS 1165%-3.0 mm
US 10287 mmUS 1117%-7.0 mm
US 10.5290 mmUS 110%-10.0 mm
US 11293 mmUS 110%-13.0 mm
US 11.5297 mmUS 110%-17.0 mm
US 12300 mmUS 110%-20.0 mm
US 12.5303 mmUS 110%-23.0 mm
US 13307 mmUS 110%-27.0 mm
US 14313 mmUS 110%-33.0 mm

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Frequently Asked Questions

How does the Tree Runner size compare to the Cloud 6?

Both shoes share a very similar length profile. We recommend ordering your standard size in both. The Tree Runner has an internal fit offset of 0mm compared to 0mm for the Cloud 6.

Do these shoes fit wide feet comfortably?

The Tree Runner has a standard medium width profile, while the Cloud 6 is standard medium.