Best Electrical Box Fill Calculator Apps

212+ iOS apps curated and reviewed

4.5 avg rating
15 free apps
Updated May 2026

If you already know NEC Box & Conduit Calc, this is the deeper bench. 212+ electrical box fill calculator apps for iPhone, all reviewed and ranked by user rating, recency, and download trend as of May 2026.

Top Picks for Electrical Box Fill Calculator

Southwire® Conduit Fill Calc#2

Southwire® Conduit Fill Calc by Southwire Company

Strong Contender
🔧 Utilities
4.5😊(679 ratings)
Free
Southwire® Conduit Fill Calc screenshot 1
Southwire® Conduit Fill Calc screenshot 2
Southwire® Conduit Fill Calc screenshot 3

This application helps electricians, engineers, and contractors quickly determine the proper conduit size to use based on NEC guidelines, including fill percentages and jam probability. Simply input conduit type, size, and conductors, and the app will calculate the conduit fill percentage for you.

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

Room to Improve

  • ⚠️ Accuracy issues reported by multiple users
  • ❌ Limited wire gauge options (missing 16 & 18 AWG)
  • 🔄 Changing conduit type erases conduit size

More Electrical Box Fill Calculator apps to explore

4
Electrician's Sidekick
Electrician's Sidekick
Electrician's Sidekick
by IDEAL INDUSTRIES, INC
Free

This free tool combines multiple electrical calculators into one convenient app, allowing electricians to efficiently and accurately complete tasks such as conduit bending, wire sizing, and voltage drop calculations. With its various calculators and features, it helps electricians maximize their fieldwork efficiency and accuracy, and is available for use even without internet connectivity.

📊 Productivity
(16)
5
National Electricians Calc
National Electricians Calc
National Electricians Calc
#1 Electrical Calculator
Free
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(1)
6
Box Fill Calc NEC
Box Fill Calc NEC
Box Fill Calc NEC
NEC Art.314 Box Volume
$0.99
🔧 Utilities
(0)
7
Box Fill 2
Box Fill 2
Box Fill 2
by Snappy Appz Inc.
$3.99

This application is a comprehensive calculator for electricians, contractors, and engineers, combining electrical box fill calculations with construction math in one intuitive interface, helping users stay compliant and efficient on the job site. With expert calculations, full construction features, and modern tools, it streamlines workflow and boosts productivity, making it an essential toolkit for professionals - download it today to upgrade your workflow.

🔧 Utilities
(2)
8
ElectriCalc Pro
ElectriCalc Pro
ElectriCalc Pro
Electrician NEC Calculator
Free
$29.99 | 100% OFF

This electrical code calculator app helps electrical contractors, designers, and specialists solve complex calculations in seconds, ensuring conformance with the latest National Electrical Code (NEC). Try it for free before buying, and discover a comprehensive electrical reference tool that saves time, trouble, and money.

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9
Box Fill Calc
Box Fill Calc
Box Fill Calc
by Snappy Appz Inc.
$4.99

This application helps users quickly and easily create schedules of box fill calculations for jobs of any size, allowing for professional and consistent results. With its user-friendly features, users can solve calculations for various box sizes, save and export results, and even print directly from the app.

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(6)
10
Electrical Calculations
Electrical Calculations
Electrical Calculations
by Egal Net di Ettore Gallina
Free
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(125)
11
Southwire® Voltage Drop Calc
Southwire® Voltage Drop Calc
Southwire® Voltage Drop Calc
Southwire Calculator
Free

Calculate the right wire size for your electrical circuit with this voltage drop calculator. Ensure proper conductivity while meeting specific voltage drop limits and NEC ampacity standards. Perfect for AWG and KCMIL sizes in various applications.

🔧 Utilities
(1.4K)
12
AWG Calculator: Wire Size
AWG Calculator: Wire Size
AWG Calculator: Wire Size
Electrician Wire Tool
Free

This electrical calculation tool simplifies wire size and other calculations following NEC standards, making it ideal for professionals and DIYers. Download now and try it for free for a month to streamline your electrical design and installation work.

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13
Electrical Code-A-Day
Electrical Code-A-Day
Electrical Code-A-Day
Quiz for Electricians
Free

Put your electrical knowledge to the test with this daily quiz app for electricians! Answer a new question each day or binge-answer them all at once. Perfect for apprentices, journeymen, and masters looking to sharpen their skills or refresh their knowledge. Lightning-fast learning on all things electrical!

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14
Electrician Tools: Calc & Bend
Electrician Tools: Calc & Bend
Electrician Tools: Calc & Bend
Bend, Size, Fill—All in One
Free
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(0)
15
Master Electrician Ref. Lite
Master Electrician Ref. Lite
Master Electrician Ref. Lite
A handbook for electricians
Free

A comprehensive electronic pocket electrician reference guide for electrical professionals and enthusiasts, providing essential information, calculations, NEC tables, and safety manuals. Visit MasterSparky.com for more details and upgrade to the full version for extensive content covering NEC codes over various years.

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16
Electrical Calc Pro
Electrical Calc Pro
Electrical Calc Pro
by Snappy Appz Inc.
$19.99

This professional electrical application is an essential tool for electricians and engineers, providing calculations for various electrical problems, including wire sizing, conduit sizing, and fusing, based on the Canadian Electric Code. With its numerous features, it helps users with tasks such as motor load calculations, transformer sizing, feeder calculations, and more, making it a comprehensive solution for electrical design and planning.

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17
Conduit Fill Pro
Conduit Fill Pro
Conduit Fill Pro
Capacity Calculator & Code
Free
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(0)
18
Electrical Calculator lite
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19
Calculator‰
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Calculator‰
Default Calculator
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Experience a beautifully designed calculator with large buttons and a clear display for quick and efficient calculations. Try it now to discover the simplicity and ease of use for your everyday arithmetic needs.

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(404K)
20
Ugly's Electrical References
Ugly's Electrical References
Ugly's Electrical References
by Informed Publishing
$12.99

This app is a comprehensive electrical reference guide that has been updated to align with the 2020 National Electrical Code. It offers a range of features such as calculators, interactive tools, and in-depth information for electricians, making it a valuable on-the-job resource.

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