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Enter your values, then click Calculate result.How this calculator helps
This wire length calculator separates a cable-jacket route from the total length of individual conductors following that route. Enter one measured route, the number of identical routes, conductors per route, extra termination or slack per conductor per route and an explicit ordering allowance. The result is a quantity takeoff, not a wire-size or voltage-drop calculation. A three-core cable bought by jacket length must not be ordered as three times that length merely because it contains three conductors. The two outputs remain separately labeled so the purchasing basis can match the actual product.
How to use it
- 1
Measure the actual one-way route and identify identical routes, conductors and your extra termination length per conductor per route.
- 2
Enter the values in the displayed units and verify the source record or measurement basis.
- 3
Click Calculate result to submit the current inputs.
- 4
Read the labeled outputs with the methodology and checks. Input edits retain the previous result until Calculate is clicked again.
Formula and methodology
Length per conductor per route = measured route + supplied extra length. Jacket-route takeoff = that length × routes. Individual-conductor takeoff = jacket-route takeoff × conductors. Planned individual length = takeoff × (1 + allowance/100).
The calculator applies the displayed arithmetic to the values entered on this device. It does not silently load a local tax rate, currency conversion or commercial assumption.
Worked calculation example
A 20 m route with 2 identical runs, 3 conductors per run, 1 m extra per conductor per route and 10% allowance gives 42 m jacket-route takeoff, 126 m individual-conductor takeoff and 138.6 m planned individual length.
How to interpret your result
A 20 m route with 2 identical runs, 3 conductors per run, 1 m extra per conductor per route and 10% allowance gives 42 m jacket-route takeoff, 126 m individual-conductor takeoff and 138.6 m planned individual length. Length takeoff only. No path optimization, wire-size selection, voltage-drop calculation, circuit design, spool-size rounding or electrical installation approval. Compare the main quantity with the separately labeled intermediate values before using it in another worksheet. Retain units, input basis and any selected convention with the result so it can be reproduced.
For different inputs or formulas, use Wire Size Calculator; Ohms Law Calculator; Watt Hour Calculator.
Related questions this calculator covers
- wire length calculator
Scenario comparison
| Scenario | What it shows |
|---|---|
| 20 m + 1 m extra over 2 routes | 42 m jacket-route takeoff. |
| Three conductors per route | 126 m individual takeoff. |
| Ten-percent ordering allowance | 138.6 m individual length. |
Common mistakes to avoid
- Ordering a multi-core jacket as multiplied individual-wire length.
- Counting termination tails twice.
- Treating length alone as wire-size or circuit approval.
Reconcile the measured path schedule, identical-route count and conductor count. Check that individual takeoff divided by conductors equals jacket-route takeoff. Independently verify slack and purchasing increments, then keep quantity arithmetic separate from electrical design.
Authoritative reference. NIST documents length units and conversions. Route and conductor takeoff are the disclosed multiplication model, not an electrical design standard. Reference reviewed 4 October 2026. Mohammad Qasim reviews the arithmetic and editorial scope; individual professional assessment is not performed.What can affect the result?
Measure the actual path rather than endpoint distance
A route can rise, turn, pass through designated pathways and terminate away from the direct line between endpoints. Measure the intended path from the actual layout rather than simply using room length. This worksheet has no automatic routing or bend allowance. If different runs have different lengths, calculate them separately instead of pretending they are identical. Keep a route schedule so a later layout change can be reconciled with the original quantity and conductor totals.
Routes and conductors are separate counts
Routes means how many identical paths are being repeated. Conductors means how many individual wires follow each of those paths. A multi-core cable often uses jacket length as its purchasing quantity, whereas separate single conductors use their summed length. The calculator reports both before the percentage allowance, making the distinction visible. Do not multiply a supplier’s already aggregated cable length by the conductor count again. Check product packaging and the bill-of-materials basis before ordering.
Extra length applies to each conductor in each route
The extra field is the combined termination and slack allowance you supply for one conductor on one route. It is added to the measured path before the route and conductor multiplications. It does not prescribe how much slack is required or where it belongs. If your route measurement already includes termination tails, do not enter them again. A fixed extra length differs from a percentage ordering buffer, so keep the reasons for both adjustments separate in the takeoff record.
Percentage allowance changes purchasing quantity
The explicit percentage applies to the total individual-conductor takeoff. Zero lets you inspect the raw route and conductor arithmetic. Ten percent multiplies the takeoff by 1.10, without rounding to a reel size or automatically adding damaged lengths. Suppliers can sell different spool lengths or minimum increments, which require another purchasing step. The page deliberately leaves those increments out rather than implying that the displayed continuous length is an available sealed package.
Length does not establish electrical suitability
Longer paths can matter to voltage drop and circuit behavior, but this calculator does not select conductor material, cross-section, insulation, protection or installation method. It gives no current rating or code approval. Use an appropriate separately verified electrical design and actual product instructions before installation. The related wire-size tool answers a different intent and should not be confused with a quantity takeoff. A correct length schedule cannot substitute for inspection of the circuit or its operating conditions.
Privacy and browser processing
Values entered on this page are processed in the current browser session. SolvePilot does not require an account and does not receive the values entered into the calculator. Refreshing or closing the page clears the working values unless the browser itself restores a previous session. Avoid entering identifying or account information because the calculation needs summary values only.
Accuracy and verification
Accuracy depends first on input quality. Confirm definitions, scales, dates and source information before entering a value. Keep an independent record of any result used for planning because this page does not create an official statement or retain a calculation history.
Limits of this estimate
Length takeoff only. No path optimization, wire-size selection, voltage-drop calculation, circuit design, spool-size rounding or electrical installation approval. Results use the entered assumptions and do not verify their real-world applicability. Calculator inputs are processed locally by the browser interface. Avoid entering identifying records; save only the quantities and context necessary for your own review.
Sources and review information
Frequently asked questions
Is wire length the same as cable length?＋
Not always. Jacket length follows each cable route, while individual-conductor length sums the wires inside or along those routes.
Does slack apply once overall?＋
No. Here it is supplied per conductor per route, and is added before the route and conductor multiplications.
Can different route lengths be combined?＋
Calculate them separately and add matching quantity outputs. The identical-route count assumes equal path lengths.
Does this choose wire gauge?＋
No. Ampacity, voltage drop, insulation, circuit protection and code requirements need a separate design.
Are reel sizes rounded?＋
No. The output is continuous length. Confirm the actual purchasing increments with your supplier.