Conduit Fill Calculator | MJJ Tools

Conduit Fill Calculator

Calculate electrical conduit fill capacity for NEC compliance with comprehensive wire and conduit database

Conduit Selection

Conduit Type and Size

Wire Configuration

No wires added yet. Click "Add Wire" to start.

NEC Fill Guidelines

1 conductor:53% max fill

2 conductors:31% max fill

3+ conductors:40% max fill

Based on NEC Article 314.16 and Chapter 9, Table 1

Features

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NEC Compliance

Automatic NEC Article 314.16 compliance checking

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Multiple Conduit Types

EMT, IMC, RMC, and PVC Schedule 40 support

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Wire Database

Comprehensive THWN/THHN and XHHW wire data

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Detailed Reports

Professional calculation reports for documentation

How to Use This Calculator

Step-by-Step Guide

1Select your conduit type and size from the dropdown menu.
2Click "Add Wire" to add conductors to your configuration.
3For each wire, specify the AWG size, insulation type, and quantity.
4Review the fill analysis and NEC compliance status in real-time.
5Copy the detailed report for your electrical plans or documentation.

Important Notes

• This calculator uses NEC Chapter 9, Table 1 fill percentages
• Wire areas include insulation thickness per NEC requirements
• Equipment grounding conductors may have different requirements
• Always verify calculations with local electrical codes
• Consider derating factors for temperature and bundling
• This tool is for reference only - consult a licensed electrician