Southwire® Conduit Fill Calc 4+

Southwire Company

Designed for iPad

    • 4.5 • 402 Ratings
    • Free



Southwire has created this great tool to help electricians, engineers and contractors answer the question, “What size conduit do I use” per the NEC®, includes fill percentages and jam probability.  If you do not have the NEC book handy or do not want to spend time manually calculating the Conduit Fill %, this is the right app for you.

The app provides quick and easy navigation.  Enter the Conduit Type and Size and specify your conductors.  The App will calculate the Conduit Fill % as per NEC Guidelines. 

Southwire Company is North America’s leading manufacturer of wire and cable used in the distribution transmission of electricity.  Throughout its history, our company has sought to deliver power through our products, our service and by helping empower our customers, employees and communities.

The App Answers the question, “What size conduit do I use” includes fill percentages and jam probability per the NEC®.  With one click, you can email your results.

What’s New

Version 2.1.13

Performance enhancements

Ratings and Reviews

4.5 out of 5
402 Ratings

402 Ratings

Rod0915 ,


I like the fact that I can build my one cable data if needed.

howieguthrie ,

This app will lie to you!

Don’t use this app! I work as an electrician and used this app for a conduit fill on a nipple between two panels. I had (4) 350 xhhw and (1) 1/0 xhhw and it came out to 56% fill for a 2 inch emt. Used a 2 inch emt for my nipple and inspector called me on it. I calculated it out via 2020 nec and sure enough it came out to 67% fill over the 60% max. Made me look stupid and wasted time. We’re trained to trust our tools but apparently you can’t this one.

mwallis kw ,

Works, but...

The app really should have an option to tell you the total number of wires per type to said type of conduit. Rather than having to plug in all the numbers manually to find the max number

App Privacy

The developer, Southwire Company, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy.

Data Not Linked to You

The following data may be collected but it is not linked to your identity:

  • Location
  • Usage Data
  • Diagnostics

Privacy practices may vary, for example, based on the features you use or your age. Learn More

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