Cable drum length and weight calculator
Enter the drum’s flange diameter, barrel diameter and inside traverse width with the cable’s overall diameter. The calculator gives layers, turns per layer, the length that fits with your freeboard and, with the cable weight, the gross drum weight for transport.
Basis
Layer-wound geometry: length = Σ π (barrel + d (2k − 1)) × turns per layer, for k = 1 to the number of full layers.
Reference values for planning and comparison. Confirm against the current standard, the purchaser’s specification and the manufacturer’s datasheet before ordering.
Worked example: How much 45 mm cable fits on an 1800 mm drum
- Winding depth = (1800 − 900) ÷ 2 − 50 = 400 mm → 8 layers of 45 mm.
- Turns per layer = 1100 ÷ 45 → 24.
- Length = Σ π × (900 + 45 × (2k − 1)) × 24 for k = 1…8 ≈ 760 m.
How do you calculate cable length on a drum?
Work out how many layers fit between the barrel and the flange less the freeboard, and how many turns fit across the traverse. Each layer’s length is its mean circumference times the turns; add the layers.
What freeboard should be left on a cable drum?
A clearance of at least one cable diameter, often 50 mm or more, between the top layer and the flange edge protects the cable in handling. Follow the manufacturer’s packing standard.
Is the calculated length exact?
It is a geometric estimate for neat layer winding. Real drums vary with winding tension and nesting, so confirm the drum schedule with the manufacturer.