Rope Diameter Converter
Convert rope and cable diameters between metric and imperial with load capacity estimates
Diameter Conversion
Millimeters
10 mm
Decimal Inches
0.39"
Fractional (nearest)
3/8"
Rope Properties
Circumference
31.42 mm
Cross Section
78.54 mm²
Working Load (est.)
305.81 kg
674.31 lbs
Breaking Strength (est.)
15,000 N
5:1 safety factor
* Estimates based on typical nylon rope. Actual values vary significantly by material and construction.
Common Rope Types
Size Reference Chart
| Metric | Imperial | Common Use |
|---|---|---|
| 4 mm | 5/32" | Light utility, paracord |
| 6 mm | 1/4" | Accessory cord, light rigging |
| 8 mm | 5/16" | Light climbing, utility |
| 10 mm | 3/8" | Standard climbing, marine |
| 12 mm | 1/2" | Static lines, dock lines |
| 16 mm | 5/8" | Heavy marine, rigging |
| 19 mm | 3/4" | Bull rope, heavy rigging |
| 22 mm | 7/8" | Tow lines, mooring |
| 25 mm | 1" | Heavy duty towing |
| 32 mm | 1-1/4" | Ship mooring |
Rope Safety Information
Working Load Limit (WLL): Maximum load for normal use. Typically 1/5 of breaking strength (5:1 safety factor).
Breaking Strength: Force required to break the rope under ideal lab conditions. Never approach this in actual use.
Safety Factors: 5:1 for general use, 10:1 for life safety (climbing, rescue), 15:1+ for overhead lifting of people.
Knots reduce strength: Most knots reduce rope strength by 25-50%. Factor this into load calculations.
Inspection: Retire ropes showing wear, fuzziness, stiffness, discoloration, or flat spots.