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Best Electrical Conduit Fill Apps

249+ iOS apps curated and reviewed

4.2 avg rating
15 free apps
Updated September 2026

Southwire® Conduit Fill Calc is the household name in electrical conduit fill, but it's far from the only option. We track 249+ alternatives and competitors on iOS — many free, many higher-rated than you'd expect.

Compare top Electrical Conduit Fill Apps (September 2026)

#AppPriceRatingAdsIn-App PurchasesUpdated
1Southwire® Conduit Fill CalcSouthwire® Conduit Fill CalcFree4.5★ (746)NoNoSep 2026
2Mike Holt's Electrical ToolboxMike Holt's Electrical ToolboxFree4.6★ (197)NoNoAug 2026
3FILL ◦ Conduit Fill CalculatorFILL ◦ Conduit Fill CalculatorFree4.0★ (3)NoYesSep 2026
4Conduit Fill Capacity CalculatorConduit Fill Capacity CalculatorFree4.0★ (1)NoNoAug 2026
5Prysmian Group Conduit FillPrysmian Group Conduit FillFree3.0★ (2)NoNoSep 2026
6TrueFill: Conduit FillTrueFill: Conduit FillFree—NoNoJul 2026
7NEC Box & Conduit CalcNEC Box & Conduit CalcFree4.9★ (19)NoYesAug 2026
8Electrical Toolkit by HCPElectrical Toolkit by HCPFree4.6★ (68)NoNoSep 2026

Top Picks for Electrical Conduit Fill

Southwire® Conduit Fill Calc#1

Southwire® Conduit Fill Calc by Southwire Company

Editor's Choice
🔧 Utilities
4.5😊(746 ratings)
Free
Southwire® Conduit Fill Calc screenshot 1
Southwire® Conduit Fill Calc screenshot 2
Southwire® Conduit Fill Calc screenshot 3

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.

What We Love

  • 🚀 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

Room to Improve

  • ⚠️ 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
FILL ◦ Conduit Fill Calculator#3

FILL ◦ Conduit Fill Calculator by James McKinney

NEC 2026 & 2023 Wire Sizing
Worth Considering
🔧 Utilities
4.0(3 ratings)
FreeIn-App Purchases
FILL ◦ Conduit Fill Calculator screenshot 1
FILL ◦ Conduit Fill Calculator screenshot 2
FILL ◦ Conduit Fill Calculator screenshot 3
FILL ◦ Conduit Fill Calculator screenshot 4
FILL ◦ Conduit Fill Calculator screenshot 5

This app calculates conduit fill percentages based on NEC 2023 standards. It helps electricians determine if wires will fit in a conduit or find the smallest suitable conduit for a given set of wires. Features include real-time status updates, history, and export options.

More Electrical Conduit Fill apps to explore

FAQ about Electrical Conduit Fill

What are the best electrical conduit fill apps for iPhone?
Southwire® Conduit Fill Calc tops our electrical conduit fill apps ranking as of September 2026, with a 4.5-star average from 746 App Store ratings, and it's free to download.
Yes — 15 of the top electrical conduit fill apps we rank are free to download, including Southwire® Conduit Fill Calc and Mike Holt's Electrical Toolbox.
Southwire® Conduit Fill Calc has no ads and has no in-app purchases, according to its App Store listing as of September 2026.
We track 249+ electrical conduit fill apps on the iOS App Store as of September 2026, ranked by rating, recency, and analysis of real user reviews.
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?'
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.