Conduit Fill Calculator
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Did you know? One 4″ EMT can hold more cable than four 2″ EMTs. Here’s why →
FREE TOOLS · PRACTICAL PLANNING
Plan your installation
with confidence.
Built for low-voltage installers, electricians, designers, and engineers.
- Size & compareConduit, conductors, boxes, and pathways.
- Design & documentFiber links, rack elevations, and clear project reports.
Project details (optional)Optional details for PDF and CSV reportsAdd details
Choose your conduit
Conduit 1
Select the raceway type and trade size for this calculation.
Cables
Add one row for each cable type in the conduit.
Cable 1Select cable detailsSelect cable
Fill criteria
Choose the permitted fill limit used for the calculation.
Bends and pulling allowance0° entered — no bend reductionConfigure
NEC conduit-fill percentages do not change based on the number of bends. Select an optional manufacturer/project method only when required by the cable manufacturer, project specification, or authority having jurisdiction.
Calculation Results
Select a cable to begin
Choose a manufacturer and cable product, or select Custom round cable to enter an outside diameter.
Export this calculation
Create a field-ready record containing the inputs, detailed results, conduit plan, calculation formulas, and verification notes.
Correct the calculator inputs before exporting or sharing.
- Select a cable to begin.
For a formatted report with page numbers, choose Download PDF report. When using browser printing, turn off Headers and footers in the print settings to omit the browser title and address.