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Southwire® Conduit Fill Calc

Southwire® Conduit Fill Calc

by Southwire Company

746 ratings
46 reviews
🔧 Utilities
💼 Business
Free

Details

  • Released
  • Updated
  • March 19, 2012
  • June 17, 2026

Features

Developer

Southwire Company
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About

This tool assists electricians, engineers, and contractors in determining the correct conduit size based on NEC guidelines. It calculates conduit fill percentages and jam probability, saving time compared to manual calculations.

✓Conduit size calculation
✓NEC fill percentages
✓Jam probability
✓Email results
✓Quick navigation
Show original description

What users say

Summarized from real user reviews of Southwire® Conduit Fill Calc. Based on 746 reviews and a 4.5/5 average, it highlights the 8 positives and 7 negatives reviewers mention most about this Utilities app.

Positive things

  • 🚀Quick and easy calculations
  • 👍User-friendly interface with spin wheel controls
  • 📊Shows actual fill percentage and NEC compliance
  • 🔧Ability to add multiple wire sizes simultaneously
  • 💾Customizable wire data entry
  • ⚡Saves significant time on job sites
  • 🎯Accurate calculations (when working properly)
  • 📱Convenient mobile access to conduit fill information

Negative things

  • ⚠️Accuracy issues reported by multiple users
  • ❌Limited wire gauge options (missing 16 & 18 AWG)
  • 🔄Changing conduit type erases conduit size
  • 📉Jam probability calculations unreliable
  • 🗑️No data persistence between calculations
  • 🐛Blank screen crashes on older versions
  • ⚠️Discrepancies with NEC standards calculations
See all reviews

What's New in Southwire® Conduit Fill Calc

2.5

June 17, 2026

Added new banner and improved the look of the button that takes you to the user-defined outer diameters screen.

User reviews

Most RecentHighest RatedLowest Rated

Florida

My go to app for quick calculations
Dave 810Dave 810

Good but slightly off

Love the app except I’ve had others check me after I’ve used and found a small deficiency of accuracy not severe
TannerwjTannerwj

Basically Worthless

The reason I say this is because we work with 0-10 lightning controls a lot, which means that without 16 & 18 awg, this utility is incomplete. Disappointing really…
MrSparkie63MrSparkie63

Amazing

This app is simple to use and works. Ask Google about wire fill and you get an answer based on people’s opinion which is mostly wrong. This app calculates it and you know exactly if you’re good to go or not.
RMTFamilyRMTFamily

Very Helpful

Best part about the app is you can add as many different sized wires as you want. Online you can only use one size at a time.
Ty-wireTy-wire
See 41 more reviews

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User experience

🐞

Reported Bugs

6 issues

Blank white screen on app launch

Bug

Conduit size data erased when changing conduit type

Bug

Inaccurate fill calculations compared to NEC standards

Bug

Jam probability calculations not accurate

Bug

App crashes and fails to display results

Bug

No method to reload or recover from crashes

Bug
✨

Requested Features

8 requests

Add 16 & 18 AWG wire sizes

Feature

Include bare solid copper and other conductor types

Feature

Save calculation history/results

Feature

Voltage drop calculator

Feature

Maximum wire count per conduit type calculator

Feature

Conduit length parameter

Feature

Restore calculate button functionality

Feature

Auto-fill missing fields

Feature

FAQ

What does the Conduit Fill Calc app do?

This app helps electricians, engineers, and contractors determine the correct conduit size by calculating the conduit fill percentage and jam probability according to NEC guidelines. It simplifies the process of answering the question, 'What size conduit do I use?'

What are the key features of this app?

Key features include calculating conduit fill percentages and jam probability based on NEC guidelines, easy navigation, and the ability to email your calculation results with a single click. It eliminates the need for manual calculations or referencing the NEC book.

Is this app free to use?

Yes, the application is provided for free. There are no in-app purchases or advertisements mentioned, indicating it is a completely free utility.

What information do I need to use the app?

To use the app, you will need to enter the Conduit Type and Size, and then specify your conductors. The app will then calculate the Conduit Fill % as per NEC Guidelines.

Who is this app designed for?

This app is specifically designed for professionals in the electrical industry, including electricians, engineers, and contractors who regularly need to calculate conduit fill and ensure compliance with NEC standards.