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Best Electrical Conduit Fill Apps

249+ iOS apps curated and reviewed

4.3 avg rating
14 free apps
Updated July 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 (July 2026)

#AppPriceRatingAdsIn-App PurchasesUpdated
1Southwire® Conduit Fill CalcSouthwire® Conduit Fill CalcFree4.5★ (746)NoNoAug 2026
2FILL ◦ Conduit Fill CalculatorFILL ◦ Conduit Fill CalculatorFree4.0★ (3)NoYesJul 2026
3Conduit Fill Capacity CalculatorConduit Fill Capacity CalculatorFree4.0★ (1)NoNoMay 2026
4NEC Box & Conduit CalcNEC Box & Conduit CalcFree4.9★ (18)YesYesJul 2026
5Southwire® Voltage Drop CalcSouthwire® Voltage Drop CalcFree4.6★ (1.5K)NoNoAug 2026
6Electrical Toolkit by HCPElectrical Toolkit by HCPFree4.8★ (18)NoNoAug 2026
7Mike Holt's Electrical ToolboxMike Holt's Electrical ToolboxFree4.6★ (197)NoNoJul 2026
8Conduit FillConduit Fill$4.993.3★ (3)NoNoAug 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

Room to Improve

  • ⚠️ Accuracy issues reported by multiple users
  • ❌ Limited wire gauge options (missing 16 & 18 AWG)
  • 🔄 Changing conduit type erases conduit size
FILL ◦ Conduit Fill Calculator#2

FILL ◦ Conduit Fill Calculator by James McKinney

NEC 2026 & 2023 Wire Sizing
Strong Contender
🔧 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

4
NEC Box & Conduit Calc
NEC Box & Conduit Calc
NEC Box & Conduit Calc
NEC Box & Conduit Fill
Free

Calculate electrical box and conduit fill accurately according to the NEC. This app provides instant, reliable calculations for electricians, contractors, and students, saving time on job sites. It offers support for various box and conduit types, conductor sizes, and includes wire volume data.

Box fill calculationsConduit fill calculationsWire volume data
🔧 Utilities
(18)
free with in-app purchases
5
Southwire® Voltage Drop Calc
Southwire® Voltage Drop Calc
Southwire® Voltage Drop Calc
Southwire Calculator
Free

Calculate the appropriate wire size for electrical circuits. This tool helps determine wire size based on voltage drop and current carrying capacity, ensuring compliance with NEC ampacity limits.

Determine wire size for voltage dropCalculate voltage drop for conductor runsLimit wire size by voltage drop
🔧 Utilities
(1.5K)
free
6
Electrical Toolkit by HCP
Electrical Toolkit by HCP
Electrical Toolkit by HCP
Conduit + load calcs for pros
Free

This comprehensive mobile toolkit provides electricians and professionals with essential calculations, NEC-compliant tools, and field utilities. It offers features for conduit bending, fill calculations, load analysis, and various electrical calculators, all designed for speed and clarity.

Conduit bending calculationsNEC-compliant conduit fillResidential load calculations
🔧 Utilities
(18)
free
7
Mike Holt's Electrical Toolbox
Mike Holt's Electrical Toolbox
Mike Holt's Electrical Toolbox
Electrical Power Calculator
Free

This app provides essential calculations for electricians, inspectors, contractors, and engineers. It helps determine conductor sizing, circuit protection, race sizing, and grounding conductor sizes for various electrical equipment and services.

Conductor sizingVoltage drop limitationsCircuit protection sizing
🔧 Utilities
(197)
free
8
Conduit Fill
Conduit Fill
Conduit Fill
quickly calculate conduit fill
$4.99

This app helps electricians quickly calculate conduit fill based on the latest NEC or CEC codes. Easily add various wire types and quantities to determine the minimum required conduit size.

NEC and CEC code calculationsSupport for up to 1000 wiresSelect from different wire types
🔧 Utilities
(3)
paid
9
Prysmian Group Conduit Fill
Prysmian Group Conduit Fill
Prysmian Group Conduit Fill
Electrical Conduit Fill
Free

This tool quickly calculates the minimum conduit size required for electrical projects based on National Electrical Code standards. It supports various conductor types, insulation, and conduit options, providing essential fill data for professionals.

NEC code selection (2011, 2014, 2017)Metric or standard conductorsAllowable fill rates
📊 Productivity
(2)
free
10
Derated: Conduit Fill
Derated: Conduit Fill
Derated: Conduit Fill
Fill and Derating Calculator
$1.99

This app simplifies complex electrical calculations for electricians. It allows real-time calculation of conduit fill and wire ampacity derating, adhering to NEC guidelines. Results are accurate and easily shareable for collaboration or client communication.

Real-time conduit fill calculationSimultaneous wire ampacity deratingAdheres to NEC guidelines
📊 Productivity
(5)
paid
11
TrueFill: Conduit Fill
TrueFill: Conduit Fill
TrueFill: Conduit Fill
Conduit Fill Calculator
Free
🔧 Utilities
(0)
12
Ugly's Electrical References
Ugly's Electrical References
Ugly's Electrical References
by Informed Publishing
$12.99

This app provides electricians and electrical professionals with up-to-date digital information based on the National Electrical Code. It includes formulas, wiring diagrams, conduit bending guides, and calculators for various electrical calculations. The app is designed for on-the-job reference and works offline.

NEC 2026 updatesMathematical formulas and calculatorsConduit bending guide with videos
📊 Productivity
(1.5K)
paid
13
Conduit Fill Pro - Electrician
Conduit Fill Pro - Electrician
Conduit Fill Pro - Electrician
NEC 2023 Conduit Calculator
$2.99
🔧 Utilities
(0)
14
Box Fill Pro - Electrician
Box Fill Pro - Electrician
Box Fill Pro - Electrician
NEC 2023 Box Fill Calculator
$4.99
🔧 Utilities
(0)
15
Conduit Fill Pro
Conduit Fill Pro
Conduit Fill Pro
Capacity Calculator & Code
Free
🔧 Utilities
(0)
16
Conduit Fill & Bending Calc
Conduit Fill & Bending Calc
Conduit Fill & Bending Calc
Box Fill, EMT Bend, Ampacity
Free

This professional calculator helps licensed electricians perform complex NEC code calculations for conduit fill, voltage drop, wire sizing, and more. It offers multiple NEC code years and provides inspector-ready PDF exports with project management features. Designed for offline use in the field.

16 NEC calculatorsNEC year-aware (2017-2026)Inspector citations on results
🔧 Utilities
(3)
free with in-app purchases
17
Conduit Fill Calculator-NEC
Conduit Fill Calculator-NEC
Conduit Fill Calculator-NEC
NEC Chapter 9 Pipe Fill
$0.99
🔧 Utilities
(0)
18
Electrician's Sidekick
Electrician's Sidekick
Electrician's Sidekick
by IDEAL INDUSTRIES, INC
Free

This free tool consolidates essential electrical calculations and reference guides into a single app. It offers precise tools for conduit bending, wire sizing, voltage drop, and conduit fill, designed to enhance fieldwork efficiency and accuracy for professionals. The app functions offline, ensuring constant access to critical information.

Conduit bending calculatorWire sizing and voltage drop calculatorConduit fill calculator
📊 Productivity
(16)
free
19
Conduit Fill: NEC Calculator +
Conduit Fill: NEC Calculator +
Conduit Fill: NEC Calculator +
Wire, box fill & derating calc
Free
🔧 Utilities
(0)
20
WireSpan: Conduit Fill Calc
WireSpan: Conduit Fill Calc
WireSpan: Conduit Fill Calc
NEC Voltage Drop & Wire Size
Free
🔧 Utilities
(0)

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 July 2026, with a 4.5-star average from 746 App Store ratings, and it's free to download.
Yes — 14 of the top electrical conduit fill apps we rank are free to download, including Southwire® Conduit Fill Calc and FILL ◦ Conduit Fill Calculator.
Southwire® Conduit Fill Calc has no ads and has no in-app purchases, according to its App Store listing as of July 2026.
We track 249+ electrical conduit fill apps on the iOS App Store as of July 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.