Comparison

iEngineer vs Unit Converter

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

Head to head
About

iEngineer

Access a vast database of screw and bolt information, including dimensions, material grades, and strength properties for both US and metric fasteners. Features a comprehensive drill chart, unit conversion, and customizable material displays.

Highlights
  • Extensive US screw database
  • Metric screw database (in-app purchase)
  • Detailed dimensions and material grades
  • Strength, torque, and clamp force data
  • Head markings and 3D head models
  • Comprehensive drill chart
  • Unit conversion and data export
Features
Read full description

iEngineer is the most comprehensive database of screw/bolt information that you can find anywhere. US screws: -93 different screws from #0 to 4” -Dimensions for 9 standard head styles -74 material grades including SAE, ASTM, and other materials Metric Screws (available as in-app purchase): -210 different metric screws from M1.0 to M100 -Dimensions for 10 standard head styles for ISO, DIN, BS, and ANSI standards where available -86 material grades including 12 additional metric grades, SAE, ASTM, and other materials Displayed values for both the US and Metric screws include: -Standard dimensions -Tap sizes -Clearance hole sizes -Material strength -Recommended torque values -Clamp force -Shear force -Head markings display -3D model of head type -Standard dimensions of head type Other features: -Drill chart with 523 drill bit sizes -Fraction chart -Copy and paste data values -Fast and easy unit conversion -Ability to show/hide material grades in the interface so you only see what is relevant to you If you have any questions please contact us at support@perfectlysimpleapps.com

About

Unit Converter

This app offers a powerful and user-friendly unit converter with 16 categories, including currency, length, and temperature. It allows for custom unit lists and provides live exchange rate updates for 148 currencies. Unlock all features with a one-time in-app purchase.

Highlights
  • 16 conversion categories
  • Custom unit lists
  • Live currency exchange rates
  • 148 world currencies supported
  • User-friendly interface
Features
Read full description

Explore our elegant and powerful unit converter with 16 categories, covering almost every unit you can think of. It's user-friendly and allows you to create custom unit lists for each category. Now featuring LIVE exchange rate updates for 148 world currencies! Categories include: Angle Area Cooking Currency Data Length Mileage Power Pressure Speed Temperature Time Volume Weight Men's shoe size Women's shoe size Note that only four categories are unlocked by default. To access all 16, simply purchase the "Pro Features" In-App. Stay connected for up-to-date currency exchange rates; an internet connection is required. Elevate your conversion experience with our versatile unit converter.

Screenshots

iEngineer4 screens
Unit Converter3 screens

Verdict

The call

iEngineer and Unit Converter both sit at 4.5 stars, but that hides the real split: 86% of iEngineer's written reviews are positive against 34% of Unit Converter's. Unit Converter's advantage is ratings volume (16K vs 201) and iOS requirement (17.6 vs 26.0). On price, rating, update cadence and ads 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

Both are free to download. iEngineer sells 1 one-off in-app purchase and Unit Converter sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

ReceptionRating · Positive reviews · Number of ratings

On the App Store both sit at effectively the same score — 4.5 for iEngineer against 4.6 for Unit Converter. That said, the two scores are not equally well evidenced: Unit Converter has 16K ratings behind it against 201, so its average is the more settled of the two. Written reviews are what separate them: 86% of iEngineer's written reviews are positive against 34% of Unit Converter's.

UpkeepUpdate frequency

iEngineer ships an update every 5 months, Unit Converter every 3 months. The most recent releases landed on November 1, 2026 and November 6, 2026 respectively.

Scorecard3 real differences · 7 level
iEngineer versus Unit Converter: the parameters behind the verdict, then further details
ParameteriEngineerUnit Converter
PriceFreeFree
Rating4.5 (201 ratings)4.6 (16K ratings) — better
Positive reviews85.5% of reviews — better33.9% of reviews
Number of ratings20116K — better
Update frequencyEvery 5 monthsEvery 3 months — better
AdsNoNo
In-app purchasesYesYes
MonetizationFree with in-app purchasesFree with in-app purchases
DevicesiPhone, iPadiPhone, iPad
Requires iOS26.017.6 — better
Further details — not scored
Size12 MB10 MB
Age rating4+4+
DeveloperPerfectly Simple Apps LLCTue Nguyen Minh

Customer experience

iEngineer

All ratings197 ratings
Positive89.8%
Neutral4.1%
Negative6.1%
Written reviews159 reviews
Positive85.5%
Neutral6.3%
Negative8.2%

Unit Converter

All ratings16,120 ratings
Positive92.1%
Neutral3.3%
Negative4.5%
Written reviews298 reviews
Positive33.9%
Neutral3.7%
Negative62.4%

User reviews

iEngineer

From 201 App Store ratings

What we love

  • 🚀 Easy to navigate
  • 👍 Comprehensive information
  • 🔧 Useful for everyday work
  • ⚙️ Essential for engineers and machinists
  • 💡 Saves time compared to physical references

Room to improve

  • 🐛 Occasional errors in torque and tensile strength data
  • 💰 Metric information requires paid upgrade
  • 🔍 Missing some thread types like NPT and BSPP

Unit Converter

From 16K App Store ratings

What we love

  • 👍 Easy to use
  • 🚀 Simple design
  • 👍 Covers many units
  • 👍 User-friendly layout
  • 👍 Accurate conversions

Room to improve

  • 🔒 Limited functionality without paying
  • 🔒 Most common units locked behind paywall
  • 🐛 Restore purchase not working
  • 🐛 Unreliable app support
  • 🔒 Conversion categories locked

Bugs and requests

iEngineer

Reported bugs

2 issues
  • Metric portion not working for some users
  • Camera access request for no apparent reason

Requested features

4 requests
  • Add tap drill chart
  • Include clearance hole fits
  • Improve UI for larger displays
  • Add French language support

Unit Converter

Reported bugs

3 issues
  • Conversion results not always accurate
  • App freezes or crashes on some devices
  • Purchased features not always accessible

Requested features

4 requests
  • Add calculator functionality
  • Improve currency conversion
  • Provide more unit categories
  • Allow creating custom formulas

In-app purchases

1 purchases

iEngineer

One-time1
  • Metric Screws$1.99
1 purchases

Unit Converter

One-time1
  • Pro Features$2.99

Questions

Is iEngineer free?
iEngineer is free to download, with in-app purchases available.
Is Unit Converter free?
Unit Converter is free to download, with in-app purchases available.
Which has better reviews, iEngineer or Unit Converter?
Unit Converter is rated higher. iEngineer averages 4.5 out of 5 from 201 ratings, while Unit Converter averages 4.6 from 16K ratings.
Do iEngineer or Unit Converter have ads?
Neither iEngineer nor Unit Converter shows ads.
Which is updated more often, iEngineer or Unit Converter?
iEngineer ships an update every 5 months, and Unit Converter every 3 months. Most recently, iEngineer was updated on November 1, 2026 and Unit Converter on November 6, 2026.

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