# Calibrex App vs MustDuo

The clearest difference is review sentiment: MustDuo at 100% against Calibrex App's 50%. MustDuo also leads on rating (5.0 vs 3.5). Calibrex App's advantage is device support (3 vs 1) and iOS requirement (15.1 vs 18.5). On price, ratings volume, update cadence and ads there is nothing between them.

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

MustDuo holds the better App Store score, 5.0 against 3.5. Both are backed by a comparable volume of ratings — 11 and 17 respectively. Written reviews point the same way: 50% of Calibrex App's written reviews are positive against 100% of MustDuo's.

Both ship on a similar rhythm, roughly fortnightly. Both last shipped on October 24, 2026.

## The numbers

| Metric | Calibrex App | MustDuo |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [3.5 (11 ratings)](https://appshunter.io/ios/app/calibrex-app/id6741951538/reviews) | **[5.0 (17 ratings)](https://appshunter.io/ios/app/mustduo/id6749694909/reviews)** |
| Number of ratings | 11 | **17** |
| Positive reviews | 50.0% of reviews | **100.0% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Fortnightly | Fortnightly |
| Monetization | Free | Free |
| Size | 150 MB | 59 MB |
| Requires iOS | **15.1** | 18.5 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 12+ | 12+ |
| Developer | [CalibrexInc](https://appshunter.io/developer/1485591463) | [MustDuo](https://appshunter.io/developer/1831771141) |

## What reviewers say

### 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


### MustDuo

[App page](https://appshunter.io/ios/app/mustduo/id6749694909)

This fitness app helps you build consistency and achieve your goals with real-time tracking and personalized plans. An AI coach provides guidance, motivation, and on-the-fly adjustments to keep you on track with your fitness journey.

**Highlights:** Smart workout tracking, Personalized workout plans, AI fitness coach, Habit building features, Gamified fitness experience, Progress analytics

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

**In-app purchases:** none


## Frequently asked questions

### Is Calibrex App free?

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

### Is MustDuo free?

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

### Which has better reviews, Calibrex App or MustDuo?

MustDuo is rated higher. Calibrex App averages 3.5 out of 5 from 11 ratings, while MustDuo averages 5.0 from 17 ratings.

### Do Calibrex App or MustDuo have ads?

Neither Calibrex App nor MustDuo shows ads.

### Which is updated more often, Calibrex App or MustDuo?

Calibrex App ships an update fortnightly, and MustDuo fortnightly. Most recently, Calibrex App was updated on October 24, 2026 and MustDuo on October 24, 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.*