VibraUnits vs PE Prep Pro
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
VibraUnits
This application facilitates the conversion of mechanical vibration analysis units. It supports conversions between displacement, velocity, and acceleration, along with frequency and various amplitude scales.
- Velocity, acceleration, displacement conversion
- Frequency conversion (Hz to CPM)
- Displacement conversion (mils to microns)
- Velocity conversion (inch/s to mm/s)
- Acceleration conversion (G's to m/s^2)
Read full descriptionHide full description
VibraUnits converts amplitudes of the most commonly used units in mechanical vibration analysis. The vibration equations used for changing units between displacement-velocity-acceleration only apply to vibration occurring at a discrete frequency (sinusoidal waves). Features: - Conversion between velocity, acceleration and displacement - Frequency conversion between Hz and CPM - Displacement conversion between mils and microns (RMS, 0-peak & peak-peak) - Velocity conversion between inch/s and mm/s (RMS, 0-peak & peak-peak) - Acceleration conversion between G's and m/s^2 (RMS, 0-peak & peak-peak) Disclaimer: This app is intended for educational purposes, although the calculations were made with great care, it may contain errors or inaccuracies. Using the results of the calculations is the responsibility of the user.
PE Prep Pro
This comprehensive exam preparation system offers over 1,400 realistic practice questions across 16 engineering disciplines. It provides detailed performance analytics to pinpoint weak areas and includes essential code summaries for offline study.
- 1,400+ realistic exam questions
- 16 major engineering disciplines
- Performance analytics
- Offline functionality
- Essential code summaries
Read full descriptionHide full description
PASS YOUR PE EXAM WITH CONFIDENCE - GUARANTEED RESULTS PE Prep Pro helps working engineers build confidence solving problems under exam conditions and make steady progress toward Professional Engineer licensure. Choose from more than 1,600 practice questions across 16 engineering disciplines. Work through civil, mechanical, electrical, chemical, structural, nuclear, petroleum, environmental, fire protection, control systems, mining, materials, naval architecture, industrial systems, and architectural engineering topics. Use Formula Focus to spend more time on calculation-heavy problems. Timed sets help you practice working through problems at pace, while step-by-step explanations show how to reach each answer. When you need a standard or formula, open the reference library for summaries of ASCE 7, ACI 318, AISC, ASME, IEEE, NFPA, API, OSHA, EPA, and other references. Performance tracking highlights strong topics and areas that need more work, making it easier to build a practical study plan around your exam date and engineering discipline. Continue practicing wherever your schedule takes you. MONEY-BACK GUARANTEE: We're so confident in PE Prep Pro that we offer a full refund if you're not completely satisfied.
Screenshots
Verdict
The clearest difference is review sentiment: VibraUnits at 88% against PE Prep Pro's 0%. VibraUnits also leads on price (Free vs $34.99) and rating (4.6 vs 1.7). PE Prep Pro's advantage is update cadence (every 3 weeks vs every 10 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
VibraUnits is free to download; PE Prep Pro costs $34.99 up front. Neither carries in-app purchases, so what you see is what you pay.
VibraUnits holds the better App Store score, 4.6 against 1.7. Both are backed by a comparable volume of ratings — 9 and 3 respectively. Written reviews point the same way: 88% of VibraUnits's written reviews are positive against 0% of PE Prep Pro's.
VibraUnits ships an update every 10 months, PE Prep Pro every 3 weeks. The most recent releases landed on November 1, 2026 and November 5, 2026 respectively.
| Parameter | VibraUnits | PE Prep Pro |
|---|---|---|
| Price | Free — better | $34.99 |
| Rating | 4.6 (9 ratings) — better | 1.7 (3 ratings) |
| Positive reviews | 87.5% of reviews — better | 0.0% of reviews |
| Number of ratings | 9 — better | 3 |
| Update frequency | Every 10 months | Every 3 weeks — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free — better | Paid |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 7.0 — better | 15.1 |
| Further details — not scored | ||
| Size | 8 MB | 43 MB |
| Age rating | +4 | +4 |
| Developer | Motionics LLC | Examp, LLC |
Customer experience
VibraUnits
PE Prep Pro
In-app purchases
VibraUnits
No in-app purchases
PE Prep Pro
No in-app purchases
Questions
Is VibraUnits free?
Is PE Prep Pro free?
Which has better reviews, VibraUnits or PE Prep Pro?
Do VibraUnits or PE Prep Pro have ads?
Which is updated more often, VibraUnits or PE Prep Pro?
Other comparisons
