# FLEX Stronger vs Calibrex App

The clearest difference is rating: FLEX Stronger at 4.4 against Calibrex App's 3.5. FLEX Stronger also leads on review sentiment (71% vs 50%). Calibrex App's advantage is update cadence (fortnightly vs monthly). On price, ratings volume, ads and in-app purchases there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

FLEX Stronger holds the better App Store score, 4.4 against 3.5. Both are backed by a comparable volume of ratings — 8 and 11 respectively. Written reviews point the same way: 71% of FLEX Stronger's written reviews are positive against 50% of Calibrex App's.

FLEX Stronger ships an update monthly, Calibrex App fortnightly. The most recent releases landed on October 21, 2026 and October 2, 2026 respectively.

## The numbers

| Metric | FLEX Stronger | Calibrex App |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.4 (8 ratings)](https://appshunter.io/ios/app/flex-stronger/id1452436164/reviews)** | [3.5 (11 ratings)](https://appshunter.io/ios/app/calibrex-app/id6741951538/reviews) |
| Number of ratings | 8 | **11** |
| Positive reviews | **71.4% of reviews** | 50.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Monthly | **Fortnightly** |
| Monetization | Free | Free |
| Size | 56 MB | 150 MB |
| Requires iOS | **15.0** | 15.1 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 17+ | 12+ |
| Developer | [Kinetic Performance](https://appshunter.io/developer/343232407) | [CalibrexInc](https://appshunter.io/developer/1485591463) |

## What reviewers say

### FLEX Stronger

[App page](https://appshunter.io/ios/app/flex-stronger/id1452436164)

This app revolutionizes weight training by syncing with a sensor to provide real-time performance feedback. Track, manage, and review your training like elite athletes, with automated workouts and group training options. It offers detailed metrics, video recording with data overlay, and a community feature for sharing and downloading workouts.

**Highlights:** Real-time performance feedback, Velocity-based training (VBT), Automated workouts, Group training for up to three people, Video recording with synced data, 1RM prediction, Workout creation and sharing

**Features:** macOS Compatibility

**In-app purchases:** none


### Calibrex App

[App page](https://appshunter.io/ios/app/calibrex-app/id6741951538)

This wearable device precisely tracks your weightlifting reps, rest, and movements. It provides personalized insights into your training, offering live audio coaching and tailored workouts to help you achieve your strength, speed, or endurance goals.

**Highlights:** Precise rep, rest, and movement tracking, Live audio coaching tailored to goals, Personalized insights into training performance, Advanced tracking and tailored workouts, Set Score, Difficulty Score, Speed Score, Tempo Score, Discover training trends and program balance

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

**In-app purchases:** none


## Frequently asked questions

### Is FLEX Stronger free?

FLEX Stronger is free to download, with no in-app purchases.

### Is Calibrex App free?

Calibrex App is free to download, with no in-app purchases.

### Which has better reviews, FLEX Stronger or Calibrex App?

FLEX Stronger is rated higher. FLEX Stronger averages 4.4 out of 5 from 8 ratings, while Calibrex App averages 3.5 from 11 ratings.

### Do FLEX Stronger or Calibrex App have ads?

Neither FLEX Stronger nor Calibrex App shows ads.

### Which is updated more often, FLEX Stronger or Calibrex App?

FLEX Stronger ships an update monthly, and Calibrex App fortnightly. Most recently, FLEX Stronger was updated on October 21, 2026 and Calibrex App on October 2, 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.*