Boot Sole Length (BSL) Guide
Everything you need to know about measuring, locating, and converting your ski boot's millimeter sole dimension for safe DIN calculations.
Mondo Point vs. Boot Sole Length
The most common mistake skiers make is inputting their Mondo size (e.g., 27.5) into a DIN calculator instead of their Boot Sole Length (e.g., 315mm).
- ✕Mondo Size: The inner foot/liner size in centimeters (e.g., 26.5 cm).
- ✓Boot Sole Length (BSL): Total physical exterior shell length in millimeters (e.g., 305 mm).
3 ways to find your BSL.
Examine the Heel Lug
In 95% of ski boots (Salomon, Atomic, Head, Lange, Rossignol, Tecnica), the 3-digit millimeter number is molded directly on the side or bottom of the heel.
Measure Tip-to-Tail
If the stamp has worn away from walking on parking lot asphalt, measure with a metric millimeter tape from the back of the heel lug to the tip of the toe lug.
Lookup Mondo Conversion
Use the chart below to estimate typical BSL from your Mondo or US shoe size. Note: boot shell molds vary by brand by ±3–8mm.
Mondo Size to Typical BSL Conversion Table
| Mondo (cm) | US Men | US Women | EU Size | Typical BSL |
|---|---|---|---|---|
| 21.0 / 21.5 | 3.5 / 4.0 | 4.5 / 5.0 | 34 / 35 | 255 mm |
| 22.0 / 22.5 | 4.5 / 5.0 | 5.5 / 6.0 | 35.5 / 36 | 265 mm |
| 23.0 / 23.5 | 5.5 / 6.0 | 6.5 / 7.0 | 37 / 37.5 | 275 mm |
| 24.0 / 24.5 | 6.5 / 7.0 | 7.5 / 8.0 | 38 / 39 | 285 mm |
| 25.0 / 25.5 | 7.5 / 8.0 | 8.5 / 9.0 | 40 / 40.5 | 295 mm |
| 26.0 / 26.5 | 8.5 / 9.0 | 9.5 / 10.0 | 41 / 42 | 305 mm |
| 27.0 / 27.5 | 9.5 / 10.0 | 10.5 / 11.0 | 42.5 / 43 | 315 mm |
| 28.0 / 28.5 | 10.5 / 11.0 | 11.5 / 12.0 | 44 / 44.5 | 325 mm |
| 29.0 / 29.5 | 11.5 / 12.0 | 12.5 / 13.0 | 45 / 46 | 335 mm |
| 30.0 / 30.5 | 12.5 / 13.0 | — | 46.5 / 47 | 345 mm |
| 31.0 / 31.5 | 13.5 / 14.0 | — | 48 / 49 | 355 mm |
Ready with your BSL?
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