Comparison

iAlignCalc vs Pre

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

Head to head
About

iAlignCalc

This app calculates machine shaft alignment corrections using multiple methods, including two inverted dial, face-rim, and double radial. It also calculates thermal growth and supports angular, parallel, and combined misalignments. Advanced features include PDF report generation with signatures, sketches, audio, and image attachments.

Highlights
  • Two inverted dial method calculations
  • Face-rim method calculations
  • Double radial method calculations
  • Thermal growth calculations
  • PDF report generation
  • Interactive tolerance tables and charts
  • Save and recall alignment sessions
Features
Read full description

iAlignCalc is an iPhone/iPad/iPod Touch application to calculate machine shaft alignment corrections. Features: - Calculates machine shaft alignment corrections using the two inverted dial method. - Calculates machine shaft alignment corrections using the face-rim method. - Calculates machine shaft alignment corrections using the double radial method. - Calculates thermal growth for different materials - Can be used for angular, parallel, and combined misalignments New Features in Version 1.2 for iPhone: - Interactive Shaft Alignment Specification: NASA Standard - Interactive Shaft Alignment Tolerance Table - Interactive Shaft Alignment Tolerance Chart - Report Generation Report Features: - PDF report output - Include user signature - Sketch pad to draw - Voice recording and audio attachment - Email PDF report - Save the PDF file on disk to be accessed from computer - Print the PDF to an Airprint - Include the plant location and the map in the PDF - Up to 5 image attachments from camera, library or screenshots of the alignment calculations - Include text and notes - Speech-to-text feature (Available in iPhone 4S only) New Features in Version 1.3 for iPhone: - Users can save the values and calculations for each alignment session and see them in a table based on the date, and name of the machine. Each saved session can be called and viewed later. Disclaimer: iAlignCalc is intended for educational purposes. Although the calculations done by this application were made with great care, it may contain errors or inaccuracies. Using the results of the calculations is the responsibility of the user.

About

Pre

This app guides users through pre-alignment tasks using a connected Bluetooth probe. It allows measurement and recording of run-out, bearing clearance, and soft foot, with the ability to generate instant PDF reports.

Highlights
  • Bluetooth connectivity
  • Icon-based adaptive user interface
  • Measure and record Run-Out
  • Measure and record Bearing Clearance
  • Measure and record True SoftCheck
  • Generate instant PDF reports
Features
Read full description

This is a companion app for performing pre-alignment tasks, using the RT-300/AT-10. The app guides the user through the complete pre-alignment process when using the Bluetooth® connected ACOEM Run-Out Probe. This offers a complete pre-alignment package, including the possibility to measure and record Run-Out, Bearing Clearance, and True SoftCheck. The PDF Report function provides a fast on-site reporting capability by converting saved measurement reports into PDF files. ---- Note: This app works with the ACOEM Run-Out Probe ---- Key Features: - Connected using Bluetooth® - GuideU: Our patented icon-based and color-coded adaptive user interface - Measure and record Run-Out, Bearing Clearance and True SoftCheck. - True SoftCheck - soft foot measurements directly on the feet of the machine. - Create an instant PDF-report Visit the website www.acoem.com for more information on alignment in general, the ACOEM tools and support of the app.

Screenshots

iAlignCalc4 screens
Pre4 screens

Verdict

The call

The clearest difference is iOS requirement: iAlignCalc at 7.0 against Pre's 13.0. On price, rating, ratings volume and update cadence 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. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

On the App Store both sit at effectively the same score — 5.0 for iAlignCalc against 5.0 for Pre. Both are backed by a comparable volume of ratings — 2 and 1 respectively.

UpkeepUpdate frequency

iAlignCalc ships an update every 4 months, Pre every 7 months. The most recent releases landed on September 22, 2026 and June 24, 2026 respectively.

Scorecard1 real difference · 9 level
iAlignCalc versus Pre: the parameters behind the verdict, then further details
ParameteriAlignCalcPre
PriceFreeFree
Rating5.0 (2 ratings)5.0 (1 ratings)
Positive reviews83.3% of reviews—
Number of ratings2 — better1
Update frequencyEvery 4 months — betterEvery 7 months
AdsNoNo
In-app purchasesNoNo
MonetizationFreeFree
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS7.0 — better13.0
Further details — not scored
Size5 MB67 MB
Age rating4+4+
DeveloperMotionics LLCACOEM Group

Customer experience

iAlignCalc

All ratings2 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews6 reviews
Positive83.3%
Neutral16.7%
Negative0.0%

Pre

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

iAlignCalc

No in-app purchases

None

Pre

No in-app purchases

Questions

Is iAlignCalc free?
iAlignCalc is free to download, with no in-app purchases.
Is Pre free?
Pre is free to download, with no in-app purchases.
Which has better reviews, iAlignCalc or Pre?
iAlignCalc and Pre are both rated 5.0 out of 5 on the App Store, from 2 and 1 ratings respectively.
Do iAlignCalc or Pre have ads?
Neither iAlignCalc nor Pre shows ads.
Which is updated more often, iAlignCalc or Pre?
iAlignCalc ships an update every 4 months, and Pre every 7 months. Most recently, iAlignCalc was updated on September 22, 2026 and Pre on June 24, 2026.

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