Comparison

Fault Current Calculator vs Box Fill Calc

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Fault Current Calculator

This tool helps contractors, engineers, and electricians quickly calculate available fault current on single and three-phase electrical systems. It also assists in sizing fuses and conductors for various circuits and can generate labels for service equipment.

Highlights
  • Calculate available fault current
  • Size fuses and conductors
  • Generate service equipment labels
  • Single and three-phase system support
  • NEC® 110.24 compliance
Features
Read full description

Eaton's Bussmann Series FC2 Available Fault Current Calculator application is an innovative tool developed for contractors, engineers, electricians, and electrical inspectors. This tool can be used on the Bussmann website or out in the field on a mobile device for those needing a quick and simple way to determine available fault current. With this simple tool, users can: - Calculate available fault current on single and three-phase systems - Create and send a label via email for marking the available fault current on service equipment (NEC® 110.24) - Size fuses and conductors for service, feeder, and branch circuits. This application, calculations, and other information are intended to clearly present technical information that will determine the available fault current at specific points in an electrical system. Bussmann reserves the right, without notice, to change this application and/or discontinue/ limit its distribution and/or availability. Bussmann also reserves the right to change or update, without notice, any technical information contained in this application. The data and information presented in this application are believed to be accurate. However, any and all liability for the content, or any omissions from this application, including any inaccuracies, errors, or misstatements in such data, calculations or information, is expressly disclaimed. The application, calculations and other information are provided without warranty of any kind, either expressed or implied, but not limited to, the implied warranties of merchantability, or fitness for a particular purpose. Bussmann disclaims any liability for the use of this application, calculations or other information. The complete End-User License Agreement can be found at: https://faultcurrentcalculatorpro.bussmann.com/home/eula

About

Box Fill Calc

This app simplifies electrical box fill calculations for any job size. It allows users to create and save unlimited calculations, solve for various box sizes, and export results to spreadsheets or print directly. It supports current electrical code standards and includes a built-in construction calculator.

Highlights
  • Unlimited saved calculations
  • Solve for custom and compound boxes
  • Export results to spreadsheet
  • Direct printing via AirPrint
  • Supports 2014 NEC and 2012
  • Built-in construction calculator
Features
Read full description

Box Calc is a fast, easy way to create a schedule of box fill calculations for any size of job or just to perform a single calculation on the fly. Put your pencil down and start making professional, consistent calculations today. - Universal app allows use on both iPad, and iPhone/iPod with single purchase. - Create an unlimited list of calculations that automatically save. - Solve for any size box including custom and compound. - Export your results to a spreadsheet for formatting or printing. - Print directly from the app (requires AirPrint printer). - Support for 2014 NEC and 2012. Built in construction calculator allows intermediate calculations to be performed within the app.

Screenshots

Fault Current Calculator4 screens
Box Fill Calc4 screens

Verdict

The call

The clearest difference is review sentiment: Box Fill Calc at 60% against Fault Current Calculator's 0%. Box Fill Calc also leads on in-app purchases (none vs 2) and rating (3.2 vs 3.0). Fault Current Calculator's advantage is price (Free vs $4.99) and ratings volume (27 vs 5). On update cadence, ads and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Fault Current Calculator is free to download; Box Fill Calc costs $4.99 up front. Fault Current Calculator sells 2 in-app purchases, starting at $4.99 per month. Box Fill Calc asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

Box Fill Calc holds the better App Store score, 3.2 against 3.0. That said, the two scores are not equally well evidenced: Fault Current Calculator has 27 ratings behind it against 5, so its average is the more settled of the two. Written reviews point the same way: 0% of Fault Current Calculator's written reviews are positive against 60% of Box Fill Calc's.

UpkeepUpdate frequency

Fault Current Calculator ships an update every 4 months, Box Fill Calc every 3 months. The most recent releases landed on October 23, 2026 and October 24, 2026 respectively.

Scorecard7 real differences · 3 level
Fault Current Calculator versus Box Fill Calc: the parameters behind the verdict, then further details
ParameterFault Current CalculatorBox Fill Calc
PriceFree — better$4.99
Rating3.0 (27 ratings)3.2 (5 ratings) — better
Positive reviews0.0% of reviews60.0% of reviews — better
Number of ratings27 — better5
Update frequencyEvery 4 monthsEvery 3 months — better
AdsNoNo
In-app purchasesYesNo — better
MonetizationFreemium — betterPaid
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS14.08.0 — better
Further details — not scored
Size25 MB18 MB
Age rating17+4+
DeveloperCooper Bussmann, LLCSnappy Appz Inc.

Customer experience

Fault Current Calculator

All ratings23 ratings
Positive47.8%
Neutral8.7%
Negative43.5%
Written reviews10 reviews
Positive0.0%
Neutral20.0%
Negative80.0%

Box Fill Calc

All ratings5 ratings
Positive60.0%
Neutral0.0%
Negative40.0%
Written reviews5 reviews
Positive60.0%
Neutral0.0%
Negative40.0%

In-app purchases

2 purchases

Fault Current Calculator

Subscriptions2
  • Pro Monthly Subscription7 Days trial$4.991 Month
  • Pro Annual Subscription7 Days trial$39.991 Year
None

Box Fill Calc

No in-app purchases

Questions

Is Fault Current Calculator free?
Fault Current Calculator is free to download, with in-app purchases available.
Is Box Fill Calc free?
Box Fill Calc costs $4.99, with no in-app purchases.
Which has better reviews, Fault Current Calculator or Box Fill Calc?
Box Fill Calc is rated higher. Fault Current Calculator averages 3.0 out of 5 from 27 ratings, while Box Fill Calc averages 3.2 from 5 ratings.
Do Fault Current Calculator or Box Fill Calc have ads?
Neither Fault Current Calculator nor Box Fill Calc shows ads.
Which is updated more often, Fault Current Calculator or Box Fill Calc?
Fault Current Calculator ships an update every 4 months, and Box Fill Calc every 3 months. Most recently, Fault Current Calculator was updated on October 23, 2026 and Box Fill Calc on October 24, 2026.

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