Wire harness length planner

Turn a point-to-point route into the actual wire cut length per wire — accounting for routing slack and per-end termination allowance — and total it up for cost.

Route & allowance

Routed path length

Length of the cable route, m

Number of wires

Identical wires sharing the same route

Allowance per wire end

mm per termination (strip, crimp, connector entry)

Routing factor

1.0 straight · 1.15–1.25 real panel routing

Wire price (optional)

Per metre — leaves the cost row blank if empty

Cut length per wire: 1.2m
Total wire length: 1.2m
Total wire length: 4.0ft

How to use it

Measure or estimate the physical route the wires follow (through grommets, around corners, along the chassis), multiply by a routing factor that reflects real-world slack, and add a per-end allowance for stripping, crimping and connector entry. Summing the per-wire cut length times the wire count gives the total harness length — the figure a cable planner quotes to buy wire, and the basis for the harness weight and cost.

Add the harness current capacity and harness weight calculators to complete the harness design pass.

Related parts

Browse related parts:

wire cable ties heat-shrink tubing

Frequently asked questions

How do I estimate how much wire a harness needs?

Cut length per wire = routed path length × routing factor + per-end allowance. Routing factor covers bends, bundle slack and routing deviation — use 1.15–1.25 for real panel routing, 1.0 for a straight point-to-point run. Allowance covers stripping, crimping and connector entry, typically 10–20 mm per termination.

How much extra length should I allow for routing a cable?

A routed path is rarely a straight line, so add a routing factor of 1.15–1.25 — the bundle has to dress around corners, through grommets and along the chassis. Add a per-end allowance on top for the stripped and crimped termination. For a direct point-to-point run set the factor to 1.0 and the allowance to zero to get the raw path length.

What is the total wire length for a 4-wire, 1 m routed harness?

With routing factor 1.2 and a 20 mm service allowance, each wire cuts to 1.0 × 1.2 + 0.02 = 1.22 m, so four wires total 4.88 m. Add the price per metre (if you enter it) to estimate wire cost. Pair this with the harness current capacity and weight calculators for the full design pass.

How it works

The planner models each wire as routed length × routing factor, plus an allowance per wire end for the termination. Multiplied by the wire count it gives the total length a harness needs — the figure that drives both wire purchase and finished harness weight.IC Source Direct provides this tool for reference only.

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