Comparison

Mike Holt's Electrical Toolbox vs Box Fill 2

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

Head to head
About

Mike Holt's Electrical Toolbox

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.

Highlights
  • Conductor sizing
  • Voltage drop limitations
  • Circuit protection sizing
  • Race sizing
  • Equipment grounding conductor sizing
  • Dwelling-unit service calculations
Features
Read full description

Mike Holt, the industry leader in the electrical industry (MikeHolt.com) has created an amazing, practical and useful app for the electrician, inspector, instructor, contractor and engineer. The app contains conductor sizing (including voltage drop limitations), circuit protection sizing, race sizing, equipment grounding conductor sizing for electric heating equipment (commercial and Residential), air-conditioning equipment (commercial and Residential), motors (commercial and Residential), Transformers (commercial) , and dwelling-unit service calculations and sizing.

About

Box Fill 2

This utility app helps electricians and contractors perform precise electrical box fill calculations according to the latest codes. It also includes a comprehensive construction calculator for dimensional math, area, volume, and right-angle solutions.

Highlights
  • Electrical box fill calculations
  • Construction calculator
  • Dimensional math (feet-inches-fractions, metric)
  • Area and volume calculations
  • Right-angle solutions
  • Shareable calculation reports
  • iCloud sync across devices
Features
Read full description

Box Fill 2: Electrical & Construction Calculator Stop guessing and start calculating with confidence. Box Fill 2 is the ultimate pro-grade utility for electricians, contractors, and engineers. Designed to streamline your workflow from the office to the job site, it combines a precision electrical box fill calculator with a full-featured construction calculator in one powerful, intuitive interface. EXPERT ELECTRICAL CALCULATIONS Stay compliant and safe with box fill calculations based on the latest standards, including the 2024 Canadian Electrical Code (CEC) and the 2023 National Electrical Code (NEC). Complete Fill Schedules: Create and save an unlimited list of calculations for entire projects. Advanced Device Logic: Automatically handles standard devices and "bulky" equipment (like smart dimmers or GFCIs) using the specific depth-based volume math required by the CEC. Detailed Conductor Tracking: Easily account for insulated conductors, bare grounds (with the NEC "4-ground" rule), internal clamps, and wire nuts. Custom Box Support: Use standard trade sizes or enter custom dimensions for specialized enclosures. Share & Export: Print directly from the app or share professional calculation reports via email or messaging to inspectors and team members. FULL CONSTRUCTION CALCULATOR No more switching between apps. Box Fill 2 includes a robust construction math engine designed for the trades. Dimensional Math: Work directly in feet-inches-fractions or metric units with seamless conversions. Area & Volume: Quickly solve for square footage and cubic volume for materials like concrete, drywall, and paint. Right-Angle Solutions: Instantly calculate rafters, slopes, and square-ups for precise layouts. History & Memory: Access previous calculations and save frequently used values to save time on repetitive tasks. MODERN & PROFESSIONAL FEATURES Universal Compatibility: Buy once and use on your iPhone, iPad, and Mac. iCloud Sync: Your project data stays up-to-date across all your devices automatically. Dark Mode Support: Optimized for high visibility in low-light job site conditions. Clean Interface: Ad-free, professional UI designed for speed and clarity under pressure. Put your pencil down and upgrade your toolkit. Download Box Fill 2 today.

Screenshots

Mike Holt's Electrical Toolbox4 screens
Box Fill 24 screens

Verdict

The call

The clearest difference is price: Mike Holt's Electrical Toolbox at Free against Box Fill 2's $3.99. Mike Holt's Electrical Toolbox also leads on review sentiment (77% vs 33%) and rating (4.6 vs 3.3). Box Fill 2's advantage is update cadence (every 5 weeks vs every 3 months). On ads, in-app purchases 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

Mike Holt's Electrical Toolbox is free to download; Box Fill 2 costs $3.99 up front. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

Mike Holt's Electrical Toolbox holds the better App Store score, 4.6 against 3.3. That said, the two scores are not equally well evidenced: Mike Holt's Electrical Toolbox has 197 ratings behind it against 3, so its average is the more settled of the two. Written reviews point the same way: 77% of Mike Holt's Electrical Toolbox's written reviews are positive against 33% of Box Fill 2's.

UpkeepUpdate frequency

Mike Holt's Electrical Toolbox ships an update every 3 months, Box Fill 2 every 5 weeks. The most recent releases landed on October 26, 2026 and October 22, 2026 respectively.

Scorecard7 real differences · 3 level
Mike Holt's Electrical Toolbox versus Box Fill 2: the parameters behind the verdict, then further details
ParameterMike Holt's Electrical ToolboxBox Fill 2
PriceFree — better$3.99
Rating4.6 (197 ratings) — better3.3 (3 ratings)
Positive reviews76.7% of reviews — better33.3% of reviews
Number of ratings197 — better3
Update frequencyEvery 3 monthsEvery 5 weeks — better
AdsNoNo
In-app purchasesNoNo
MonetizationFree — betterPaid
DevicesiPhone, iPad, iPod — betteriPhone, iPad
Requires iOS14.0 — better26.0
Further details — not scored
Size26 MB19 MB
Age rating4+4+
DeveloperMike Holt EnterprisesSnappy Appz Inc.

Customer experience

Mike Holt's Electrical Toolbox

All ratings197 ratings
Positive90.4%
Neutral1.5%
Negative8.1%
Written reviews30 reviews
Positive76.7%
Neutral6.7%
Negative16.7%

Box Fill 2

All ratings3 ratings
Positive33.3%
Neutral66.7%
Negative0.0%
Written reviews3 reviews
Positive33.3%
Neutral66.7%
Negative0.0%

Bugs and requests

Mike Holt's Electrical Toolbox

Reported bugs

4 issues
  • Cannot email results
  • Video player widescreen exit bug
  • Previous calculation data not erased
  • App content is outdated

Requested features

6 requests
  • Increase transformer capacity to 225kva
  • Add option to print load calc
  • Update to NEC 2020
  • Add completion system for video series
  • Refine user interface for better usability
Show 1 more
  • Add more features, willing to pay extra

Box Fill 2

Not enough reviews yet to summarise bugs or requests.

In-app purchases

None

Mike Holt's Electrical Toolbox

No in-app purchases

None

Box Fill 2

No in-app purchases

Questions

Is Mike Holt's Electrical Toolbox free?
Mike Holt's Electrical Toolbox is free to download, with no in-app purchases.
Is Box Fill 2 free?
Box Fill 2 costs $3.99, with no in-app purchases.
Which has better reviews, Mike Holt's Electrical Toolbox or Box Fill 2?
Mike Holt's Electrical Toolbox is rated higher. Mike Holt's Electrical Toolbox averages 4.6 out of 5 from 197 ratings, while Box Fill 2 averages 3.3 from 3 ratings.
Do Mike Holt's Electrical Toolbox or Box Fill 2 have ads?
Neither Mike Holt's Electrical Toolbox nor Box Fill 2 shows ads.
Which is updated more often, Mike Holt's Electrical Toolbox or Box Fill 2?
Mike Holt's Electrical Toolbox ships an update every 3 months, and Box Fill 2 every 5 weeks. Most recently, Mike Holt's Electrical Toolbox was updated on October 26, 2026 and Box Fill 2 on October 22, 2026.

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