# Flex AI Workout Trainer & Log vs Caliber

The clearest difference is rating: Caliber at 4.8 against Flex AI Workout Trainer & Log's 4.6. Caliber also leads on review sentiment (78% vs 69%) and iOS requirement (15.1 vs 18.0). On price, ratings volume, update cadence and ads there is nothing between them.

Both are free to download. Flex AI Workout Trainer & Log sells 8 in-app purchases, starting at $12.99 per month and Caliber sells 18 in-app purchases, starting at $3.00 per month. Whichever you choose, the download price is not the number that matters.

Caliber holds the better App Store score, 4.8 against 4.6. Both are backed by a comparable volume of ratings — 2.4K and 6K respectively. Written reviews point the same way: 69% of Flex AI Workout Trainer & Log's written reviews are positive against 78% of Caliber's.

Flex AI Workout Trainer & Log ships an update every 9 days, Caliber fortnightly. The most recent releases landed on October 17, 2026 and October 18, 2026 respectively.

## The numbers

| Metric | Flex AI Workout Trainer & Log | Caliber |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.6 (2.4K ratings)](https://appshunter.io/ios/app/flex-ai-workout-trainer-and-log/id1446354547/reviews) | **[4.8 (6K ratings)](https://appshunter.io/ios/app/caliber-strength-training/id1482405410/reviews)** |
| Number of ratings | 2.4K | **6K** |
| Positive reviews | 69.0% of reviews | **78.3% of reviews** |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | **Every 9 days** | Fortnightly |
| Monetization | Freemium | Free with in-app purchases |
| Size | 574 MB | 67 MB |
| Requires iOS | 18.0 | **15.1** |
| Devices | iPhone, Apple Watch | iPhone, iPod |
| Age rating | 17+ | 12+ |
| Developer | [Flex Artificial Intelligence Inc.](https://appshunter.io/developer/1446354546) | [Caliber Fitness, Inc](https://appshunter.io/developer/1482405409) |

## What reviewers say

### Flex AI Workout Trainer & Log

[App page](https://appshunter.io/ios/app/flex-ai-workout-trainer-and-log/id1446354547)

This app uses AI to provide personalized workout plans and real-time form feedback for weightlifters. It tracks progress, offers adaptive progression, and includes motivational features like leaderboards and streaks. It's designed for all experience levels, from beginners to pros.

**Highlights:** AI personal trainer, Real-time form feedback, Personalized workout plans, Adaptive progression, Strength tracking, Community leaderboards, Apple Watch integration

**Features:** Family Sharing, Apple Watch app, Vision Pro support

**In-app purchases (8)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Premium Subscription Monthly | $12.99 | per month |
| Premium Plus Monthly | $29.99 | per month |
| Premium Plus Family Monthly | $69.99 | per month |
| Premium Yearly Subscription | $79.99 | per year |
| Premium Plus Yearly | $191.99 | per year |
| Premium Plus Family Yearly | $499.99 | per year |
| 1 Month Free Premium | Free | one-time |
| Lifetime Free Premium | Free | one-time |

**What reviewers like**

- 🚀 Detailed workout tracking
- 👍 Customizable workouts
- 🔒 Comprehensive exercise library
- 💡 Helpful progress tracking
- 👍 Clean and intuitive interface

**What reviewers complain about**

- 🐛 Glitches and bugs
- 💰 Expensive premium subscription
- 🔒 Limited functionality without premium
- 🐛 Inconsistent rest timer
- 🐛 Workout data loss

**Reported bugs**

- App crashes on iOS 16 update
- Inability to log workouts on previous days
- Inconsistent syncing between app and Apple Watch

**Requested features**

- Offline workout mode
- Ability to save and reuse custom workout plans
- Muscle group targeting and analytics
- Social features and community integration


### Caliber

[App page](https://appshunter.io/ios/app/caliber-strength-training/id1482405410)

This app offers science-based strength training, including workout planning, tracking, and exercise tutorials. It supports individual training, group workouts, and offers optional upgrades for personalized plans, advanced features, and one-on-one coaching.

**Highlights:** Unlimited workout creation and tracking, 600+ exercise tutorials with videos, Workout groups for training with friends, Coach-designed training plans, Personalized progress tracking, 1-on-1 elite coaching options

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

**In-app purchases (18)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Caliber Supporter (Monthly) | $3.00 | per month |
| Caliber Supporter (Monthly) | $5.00 | per month |
| Caliber Plus (Monthly) | $6.00 | per month |
| Caliber Plus (Monthly) | $6.00 | per month |
| Caliber Supporter (Monthly) | $7.00 | per month |
| Caliber Supporter (Monthly) | $9.00 | per month |
| Caliber Plus (Monthly) | $9.00 | per month |
| Caliber Plus (Monthly) | $12.00 | per month |
| Caliber Pro (Monthly) | $19.00 | per month |
| Caliber Pro (Monthly) | $19.00 | per month |
| Caliber Plus (Yearly) | $36.00 | per year |
| Caliber Pro (3 Months) | $49.00 | per 3 months |
| Caliber Pro (3 Months) | $49.00 | per 3 months |
| Caliber Plus (Yearly) | $54.00 | per year |
| Caliber Plus (Yearly) | $72.00 | per year |
| Caliber Plus (Yearly) | $72.00 | per year |
| Caliber Pro (Yearly) | $169.00 | per year |
| Caliber Pro (Yearly) | $169.00 | per year |

**What reviewers like**

- 👍 Easy to use
- 🚀 Comprehensive workout tracking
- 💡 Customizable workouts
- 🔍 Detailed exercise instructions and videos
- 📊 Strength score and progress tracking

**What reviewers complain about**

- 🐛 Occasional app crashes and bugs
- 🔍 Limited offline functionality
- 💰 Subscription model can be confusing
- 🔍 Inconsistent video quality and exercise explanations
- 🕰️ Frustrating user interface at times

**Reported bugs**

- Workout data loss when switching between online and offline mode
- Strength score not updating correctly in some cases
- Inability to log weight for certain exercises

**Requested features**

- Add ability to create and save custom exercises
- Integrate with more fitness tracking devices and apps
- Improve offline mode to allow full workout tracking
- Provide more flexibility in workout scheduling and planning
- Enhance strength score calculations and explanations


## Frequently asked questions

### Is Flex AI Workout Trainer & Log free?

Flex AI Workout Trainer & Log is free to download, with in-app purchases available.

### Is Caliber free?

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

### Which has better reviews, Flex AI Workout Trainer & Log or Caliber?

Caliber is rated higher. Flex AI Workout Trainer & Log averages 4.6 out of 5 from 2.4K ratings, while Caliber averages 4.8 from 6K ratings.

### Do Flex AI Workout Trainer & Log or Caliber have ads?

Neither Flex AI Workout Trainer & Log nor Caliber shows ads.

### Which is updated more often, Flex AI Workout Trainer & Log or Caliber?

Flex AI Workout Trainer & Log ships an update every 9 days, and Caliber fortnightly. Most recently, Flex AI Workout Trainer & Log was updated on October 17, 2026 and Caliber on October 18, 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.*