True-to-Size Millimeter Sizing Comparison
Ariat Terrain H2O vs Dr. Martens 2976 Chelsea
Detailed size conversion chart, cavity measurements in millimeters, and crowd-sourced fit advice for choosing your perfect size.
Interactive Size Converter
Select what size you wear in the Terrain H2O to see your calculated size in the 2976 Chelsea.
Complete Size Conversion Matrix
Direct millimeter-calibrated mapping comparing all available sizes between both shoes.
| Terrain H2O (US) | Internal Cavity | 2976 Chelsea Equivalent | Match Accuracy | Fit Difference |
|---|---|---|---|---|
| US 4.5 | 234 mm | US 5 | 64% | +3.1 mm |
| US 5 | 238 mm | US 5.5 | 75% | +2.1 mm |
| US 5.5 | 241 mm | US 6 | 75% | +2.1 mm |
| US 6 | 244 mm | US 6.5 | 64% | +3.1 mm |
| US 6.5 | 248 mm | US 7 | 75% | +2.1 mm |
| US 7 | 251 mm | US 7.5 | 75% | +2.1 mm |
| US 7.5 | 254 mm | US 8 | 64% | +3.1 mm |
| US 8 | 258 mm | US 8.5 | 75% | +2.1 mm |
| US 8.5 | 261 mm | US 8.5 | 89% | -0.9 mm |
| US 9 | 268 mm | US 9.5 | 75% | +2.1 mm |
| US 9.5 | 271 mm | US 10 | 75% | +2.1 mm |
| US 10 | 274 mm | US 10.5 | 64% | +3.1 mm |
| US 10.5 | 278 mm | US 11 | 75% | +2.1 mm |
| US 11 | 281 mm | US 11 | 89% | -0.9 mm |
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Frequently Asked Questions
How does the Terrain H2O size compare to the 2976 Chelsea?
Both shoes share a very similar length profile. We recommend ordering your standard size in both. The Terrain H2O has an internal fit offset of 0.84mm compared to -0.08mm for the 2976 Chelsea.
Do these shoes fit wide feet comfortably?
The Terrain H2O has a roomy/wide width profile, while the 2976 Chelsea is snug/narrow.