# Southwire® Conduit Fill Calc

> Calculate conduit fill percentage and jam probability per NEC guidelines. (iPhone/iPad app by Southwire Company.)

- Source: https://appshunter.io/ios/app/southwire-conduit-fill-calc/id509204523 (this page in markdown: same URL + `.md`)
- Developer: [Southwire Company](https://appshunter.io/developer/440338423)
- Category: Utilities, Business
- Price: Free
- Rating: 4.48/5 from 746 App Store ratings · 47 written reviews indexed
- Age rating: 4+
- Requires: iOS 15.6 · 19 MB
- Languages: English
- Released: 2012-03-19
- Data updated: 2026-08-27
- Monetization: free
- User reviews in markdown: https://appshunter.io/ios/app/southwire-conduit-fill-calc/id509204523/reviews.md

## What is Southwire® Conduit Fill Calc?

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.

## Key features

- Conduit size calculation
- NEC fill percentages
- Jam probability
- Email results
- Quick navigation

## What do users think of Southwire® Conduit Fill Calc?

Overall sentiment: positive

**Pros**

- 🚀 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

**Cons**

- ⚠️ 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

**Commonly reported bugs**

- Blank white screen on app launch
- Conduit size data erased when changing conduit type
- Inaccurate fill calculations compared to NEC standards
- Jam probability calculations not accurate
- App crashes and fails to display results
- No method to reload or recover from crashes

**Most requested features**

- Add 16 & 18 AWG wire sizes
- Include bare solid copper and other conductor types
- Save calculation history/results
- Voltage drop calculator
- Maximum wire count per conduit type calculator
- Conduit length parameter
- Restore calculate button functionality
- Auto-fill missing fields

## Recent user reviews (10 of 47)

All indexed reviews: https://appshunter.io/ios/app/southwire-conduit-fill-calc/id509204523/reviews.md

### 5/5 — Awesome app

*2026-06-26, version 2.5*

Quick and easy. Can’t mess it up. That’s what you need in the field.

### 5/5 — Florida

*2026-02-07, version 2.3.1*

My go to app for quick calculations

### 3/5 — Good but slightly off

*2025-10-25, version 2.3.1*

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

### 2/5 — Basically Worthless

*2025-08-02, version 2.3.1*

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…

### 5/5 — Amazing

*2025-07-17, version 2.3*

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.

### 5/5 — Very Helpful

*2025-05-10, version 2.3*

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.

### 5/5 — Helpful in the field

*2024-12-08, version 2.2.2*

Thanks for the wire,conduit fill for new code requirements on fillet thanks south wire very helpful on decision making and doing things the correct way

### 5/5 — Great app for quickly calculating conduit fill.

*2024-07-23, version 2.1.15*

The app is extremely easy to use and immediately shows the actual percentage of fill. It also flags whether fill exceeds NEC requirements. With spin wheel fields for each variable, selections are quick, easy and accurate. Thanks for making this available to customers.

### 5/5 — Conduit fill

*2024-07-23, version 2.1.15*

Excellent app easy to use and saves you soo lots of time.

### 1/5 — App doesn’t work

*2024-01-23, version 2.1.15*

Typed all info but no results!!

## Frequently asked questions about Southwire® Conduit Fill Calc

### 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.

## Version history (last 5 releases)

### 2.5 — 2026-06-17

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

### 2.3.1 — 2025-07-24

New graphics.

### 2.3 — 2025-01-22

Duplicate conductor warning and unique file name for shared results.

### 2.2.2 — 2024-11-20

New banner.

### 2.2.1 — 2024-10-23

Behind the scenes update

## Apps similar to Southwire® Conduit Fill Calc

| App | Rating | Price | Category |
| --- | --- | --- | --- |
| [Electrical Calculator lite](https://appshunter.io/ios/app/electrical-calculator-lite/id922903696) | 4.6 (574) | Free | Utilities |
| [Generac Field Pro](https://appshunter.io/ios/app/generac-field-pro/id6550921902) | 3.2 (21) | Free | Utilities |
| [SolarEdge Go](https://appshunter.io/ios/app/solaredge-go/id1628098907) | 2.2 (158) | Free | Utilities |
| [Mike Holt's Electrical Toolbox](https://appshunter.io/ios/app/mike-holts-electrical-toolbox/id1406630647) | 4.6 (197) | Free | Utilities |
| [AWG Calculator: Wire Size](https://appshunter.io/ios/app/awg-calculator-wire-size/id1607173204) | 4.6 (67) | Free | Utilities |
| [Fault Current Calculator](https://appshunter.io/ios/app/fault-current-calculator/id647477910) | 3.1 (23) | Free | Utilities |

## More apps by Southwire Company

- [Southwire® Voltage Drop Calc](https://appshunter.io/ios/app/southwire-voltage-drop-calc/id440338420)
- [Partial Reel Calculator](https://appshunter.io/ios/app/partial-reel-calculator/id489177969)
- [Southwire® MCAP® Savings Calc](https://appshunter.io/ios/app/southwire-mcap-savings-calc/id509207536)
- [Proof Positive© Copper](https://appshunter.io/ios/app/proof-positive-copper/id518391353)
- [Southwire® Conversion Calc](https://appshunter.io/ios/app/southwire-conversion-calc/id545756420)

All apps by Southwire Company: https://appshunter.io/developer/440338423

## Related topics

[conduit fill](https://appshunter.io/ios/topics/conduit-fill) · [conduit fill tracker](https://appshunter.io/ios/topics/conduit-fill-tracker) · [conduit fill calculator](https://appshunter.io/ios/topics/conduit-fill-calculator) · [electrical conduit fill](https://appshunter.io/ios/topics/electrical-conduit-fill) · [southwire conduit fill](https://appshunter.io/ios/topics/southwire-conduit-fill) · [conduit calculator](https://appshunter.io/ios/topics/conduit-calculator) · [okonite](https://appshunter.io/ios/topics/okonite) · [prysmian group conduit fill](https://appshunter.io/ios/topics/prysmian-group-conduit-fill) · [conduit fill capacity calculator](https://appshunter.io/ios/topics/conduit-fill-capacity-calculator) · [southwire voltage drop calculator](https://appshunter.io/ios/topics/southwire-voltage-drop-calculator) · [electrical box fill calculator](https://appshunter.io/ios/topics/electrical-box-fill-calculator) · [nema configuration guide](https://appshunter.io/ios/topics/nema-configuration-guide) · [ugly book](https://appshunter.io/ios/topics/ugly-book) · [wire size calculator](https://appshunter.io/ios/topics/wire-size-calculator) · [wire size calculator for electricians](https://appshunter.io/ios/topics/wire-size-calculator-for-electricians) · [captain code nec code changes](https://appshunter.io/ios/topics/captain-code-nec-code-changes) · [building wire reliability calc](https://appshunter.io/ios/topics/building-wire-reliability-calc) · [uglys](https://appshunter.io/ios/topics/uglys) · [coildata](https://appshunter.io/ios/topics/coildata) · [eaton bussmann fuse finder](https://appshunter.io/ios/topics/eaton-bussmann-fuse-finder)

---

*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-27.*