Tool
Cable length estimator
The right cable length is the horizontal tray distance plus vertical drops at each end, plus slack at each end and any service loop, multiplied by a waste allowance. The estimator rounds up to the next stock length and groups multiple runs into an order.
Enter your runs below. Everything is calculated in your browser from what you type.
Your runs
Runs
Run 1
Order summary
Per-run breakdown
Run 1: 19.0 m raw, 20.9 m required → 30 m stock
How this is worked out
Every input is yours to change. An estimator with hidden allowances is not a tool.
Raw length is horizontal plus both drops plus twice the slack plus the service loop. Required length adds the waste allowance, which defaults to 10 percent for cuts, dressing and mistakes. Stock lengths run from 0.5 m to 50 m.
Anything above the longest stock length is flagged as custom, because it will need to be made to order rather than bought off the shelf.
Questions about cable lengths
How is required length calculated?
Raw length is horizontal plus both drops plus twice the slack plus the service loop. Required length adds the waste allowance, which defaults to 10 percent.
What are stock lengths?
Stock lengths are standard cables you can buy off the shelf, from 0.5 m to 50 m. The estimator rounds up to the next stock length. Anything above needs custom manufacture.
How much slack should I leave?
The default is 0.5 m per end for dressing and re-termination. More slack makes future changes easier but costs more cable and takes up tray space.
What is a service loop?
A service loop is extra cable left coiled for future moves or re-termination. It is separate from slack and waste. Enter the loop length in metres.
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