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Cable run cost and spool length.
Enter the number of runs, the average length, a slack allowance and spool details to get the cable to buy, leftover and the total cost.
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Network Cable Run Cost Calculator: how it works
The tool multiplies the average run length by the slack allowance to get the cut length per run, then by the number of runs for total cable. Dividing by the spool length and rounding up gives the spools to buy; leftover is the remainder. Cost is spools times price plus two jacks or plugs per run. A copper permanent link should not exceed 90 m, per Wikipedia's Structured cabling article, so the tool flags longer runs.
Worked example. 6 runs averaging 25 m with 10% slack are 27.5 m each, 165 m in total. One 305 m spool covers it with 140 m left over. At 120 per spool and 2 per jack or plug (12 ends = 24), the total is 144, or 24 per run.
Spools come in different lengths and the tool does not assume one: enter yours. A single box cannot be split between jobs, which is why the tool rounds up.
Frequently asked questions
How much Ethernet cable do I need?
Multiply the number of runs by the average route length plus slack, then divide by your spool length and round up. Six 25 m runs with 10% slack need 165 m.
How much slack should I add?
The tool defaults to 10% as an assumption for bends and service loops. There is no standard figure; add more for awkward routes.
What is the longest copper run?
The permanent link should be 90 m at most, with up to 10 m of patch cords, for a 100 m channel, per Wikipedia's Structured cabling article.
Why does the tool round spools up?
You buy whole spools, so a partial spool still has to be purchased.
Sources
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Slack, spool length and prices are your inputs; no published source gives them.
Runs entirely in your browser. Nothing you type is sent or stored.
Not professional advice
Cost planning aid only. Prices, spool sizes and local building and electrical codes are yours to confirm.