Wire Spool Capacity Calculator
Count complete rectangular-grid wire layers and turns that fit within a spool envelope.
YOUR CALCULATION
Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Fit whole touching turns axially and whole wire layers radially, then sum each layer centerline circumference.
Turns/layer=floor(width/wire); layers=floor((outside−core)/(2 wire)); length=Σ turns×π(core+(2j+1)wire)
Worked example
A 50 mm core, 100 mm outside limit, 100 mm width and 2 mm wire fit 50 turns per layer and 12 layers; modeled length is about 139.486714 m.
Assumptions and input details
Rectangular touching-layer packing, with no crossover allowance, traverse error, helix-length correction, hex packing or winding strain. Overall diameter includes insulation. Flange clearance must be removed from inputs.
Unit definitions
Unit selection is independent of language. Each selector contains only units for its physical quantity. Calculations use defined base units internally.
Choose from 23 length definitions, including explicitly labelled regional measures. Area conversions square the length factor; geometric volumes cube it.
Regional measures are not interchangeable merely because their names look similar. This is a documented selection, not a claim to include every historical unit.
NIST measurement tables · Japanese traditional units · Mainland China and Hong Kong unit distinctions
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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