# Vibra Calc vs PrepFE

The clearest difference is rating: Vibra Calc at 4.0 against PrepFE's 2.0. Vibra Calc also leads on in-app purchases (none vs 9) and review sentiment (50% vs 17%). PrepFE's advantage is update cadence (every 2 months vs every 39 months) and ratings volume (57 vs 2). On price, ads and device support there is nothing between them.

Both are free to download. PrepFE sells 6 one-off in-app purchases. Vibra Calc asks for nothing beyond the download.

Vibra Calc holds the better App Store score, 4.0 against 2.0. That said, the two scores are not equally well evidenced: PrepFE has 57 ratings behind it against 2, so its average is the more settled of the two. Written reviews point the same way: 50% of Vibra Calc's written reviews are positive against 17% of PrepFE's.

Vibra Calc ships an update every 39 months, PrepFE every 2 months. The most recent releases landed on October 14, 2026 and October 8, 2026 respectively.

## The numbers

| Metric | Vibra Calc | PrepFE |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.0 (2 ratings)](https://appshunter.io/ios/app/vibra-calc/id458723288/reviews)** | [2.0 (57 ratings)](https://appshunter.io/ios/app/prepfe-fe-mechanical-prep/id1455746709/reviews) |
| Number of ratings | 2 | **57** |
| Positive reviews | **50.0% of reviews** | 16.7% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 39 months | **Every 2 months** |
| Monetization | **Free** | Free with in-app purchases |
| Size | 22 MB | 288 MB |
| Requires iOS | **8.0** | 13.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Motionics LLC](https://appshunter.io/developer/424498959) | [PrepFE, Inc.](https://appshunter.io/developer/1499557437) |

## What reviewers say

### Vibra Calc

[App page](https://appshunter.io/ios/app/vibra-calc/id458723288)

This app calculates vibration frequencies for various rotating machinery components and includes an interactive vibration severity test tool. It also offers a calculator for converting vibration units and a glossary of terms.

**Highlights:** Induction motor frequency calculation, Detailed gear frequencies, Rolling element bearing frequencies, Pump and fan vane pass frequencies, Journal bearing frequencies, Interactive vibration severity test, Vibration unit conversion

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### PrepFE

[App page](https://appshunter.io/ios/app/prepfe-fe-mechanical-prep/id1455746709)

Prepare for the FE Mechanical exam with practice problems and flashcards. Learn by doing with expert-curated content, track your progress, and identify areas for improvement. Study conveniently on your mobile device, anytime, anywhere.

**Highlights:** Practice FE exam questions, Interactive practice exams, Hundreds of practice questions, Detailed step-by-step explanations, Reinforce learning with flashcards, Breakdown of strengths and weaknesses

**Features:** Vision Pro support

**In-app purchases (6)**

| Purchase | Price | Billing |
| --- | --- | --- |
| 1 Month Access Renewal | $47.99 | one-time |
| 1 Month Access | $59.99 | one-time |
| 3 Months Access Renewal | $61.99 | one-time |
| 6 Months Access Renewal | $75.99 | one-time |
| 3 Months Access | $79.99 | one-time |
| 6 Months Access | $99.99 | one-time |


## Frequently asked questions

### Is Vibra Calc free?

Vibra Calc is free to download, with no in-app purchases.

### Is PrepFE free?

PrepFE is free to download, with in-app purchases available.

### Which has better reviews, Vibra Calc or PrepFE?

Vibra Calc is rated higher. Vibra Calc averages 4.0 out of 5 from 2 ratings, while PrepFE averages 2.0 from 57 ratings.

### Do Vibra Calc or PrepFE have ads?

Neither Vibra Calc nor PrepFE shows ads.

### Which is updated more often, Vibra Calc or PrepFE?

Vibra Calc ships an update every 39 months, and PrepFE every 2 months. Most recently, Vibra Calc was updated on October 14, 2026 and PrepFE on October 8, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*