# Frontier X vs Calibre Biometrics

Frontier X and Calibre Biometrics both sit at 4.6 stars, but that hides the real split: 82% of Frontier X's written reviews are positive against 50% of Calibre Biometrics's. Frontier X also leads on ratings volume (318 vs 2). Calibre Biometrics's advantage is monetization model (free vs freemium). On price, rating, update cadence and ads there is nothing between them.

Both are free to download. Frontier X sells 2 in-app purchases, starting at $14.99 per month and Calibre Biometrics sells 1 in-app purchase, starting at $7.99 per month. Whichever you choose, the download price is not the number that matters.

On the App Store both sit at effectively the same score — 4.6 for Frontier X against 4.5 for Calibre Biometrics. That said, the two scores are not equally well evidenced: Frontier X has 318 ratings behind it against 2, so its average is the more settled of the two. Written reviews are what separate them: 82% of Frontier X's written reviews are positive against 50% of Calibre Biometrics's.

Frontier X ships an update every 2 weeks, Calibre Biometrics every 4 weeks. The most recent releases landed on November 7, 2026 and November 4, 2026 respectively.

## The numbers

| Metric | Frontier X | Calibre Biometrics |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.6 (318 ratings)](https://appshunter.io/ios/app/frontier-x/id1483444499/reviews)** | [4.5 (2 ratings)](https://appshunter.io/ios/app/calibre-biometrics/id6743721886/reviews) |
| Number of ratings | **318** | 2 |
| Positive reviews | **81.8% of reviews** | 50.0% of reviews |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | **Every 2 weeks** | Every 4 weeks |
| Monetization | Freemium | **Free** |
| Size | 569 MB | 116 MB |
| Requires iOS | 16.0 | **15.4** |
| Devices | iPhone, Apple Watch | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Fourthfrontier](https://appshunter.io/developer/1331846764) | [BreathTaking Tech LLC](https://appshunter.io/developer/1609706657) |

## What reviewers say

### Frontier X

[App page](https://appshunter.io/ios/app/frontier-x/id1483444499)

Track your heart health and exercise performance with a smart chest strap wearable. Get detailed insights into heart rate, HRV, strain, and more, with personalized training feedback and alerts. Integrates with other devices and offers advanced analytics through a premium subscription.

**Highlights:** Heart health and performance tracking, Real-time heart rate and HRV monitoring, Personalized vibration alerts, Activity recording up to 24 hours, Integration with Bluetooth wearables, AI-enabled training insights, Metabolic Profile Analytics (Premium)

**Features:** Apple Watch app

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Monthly | $14.99 | per month |
| Yearly | $119.99 | per year |

**What reviewers like**

- 🚀 Amazing device
- 👍 Great HR data and insight
- 👍 Helpful in gaining more data
- 👍 Fantastic concept with excellent execution
- 👍 Loads of useful information

**What reviewers complain about**

- 🐛 Worse and worse as time goes by
- 🐛 ECG doesn't work
- 🐛 Chest strap issues, device keeps popping out
- 🐛 Paywalled functionality
- 🐛 Syncing issues, device keeps disconnecting

**Reported bugs**

- ECG stopped working
- Inaccurate breathing rate and other metrics
- Inability to edit activity details for indoor workouts
- Syncing issues with Garmin devices after firmware updates

**Requested features**

- Add interval markers
- Improve integration with Apple Fitness/Fitness+
- Add support for ANT+
- Improve compatibility with other fitness apps and devices
- Add more customization options for workouts


### Calibre Biometrics

[App page](https://appshunter.io/ios/app/calibre-biometrics/id6743721886)

This app pairs with a wearable device to track and analyze key metabolic and performance metrics like VO2 Max and resting metabolic rate. It provides detailed insights into your body's energy expenditure and fat burning zones. Designed for informational and educational use, it complements professional health guidance.

**Highlights:** View biometric data, Record metabolic information, Analyze VO2 Max, Monitor Resting Metabolic Rate, Track FatMax and Calories, Companion to wearable tracker

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Calibre Premium | $7.99 | per month |


## Frequently asked questions

### Is Frontier X free?

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

### Is Calibre Biometrics free?

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

### Which has better reviews, Frontier X or Calibre Biometrics?

Frontier X is rated higher. Frontier X averages 4.6 out of 5 from 318 ratings, while Calibre Biometrics averages 4.5 from 2 ratings.

### Do Frontier X or Calibre Biometrics have ads?

Neither Frontier X nor Calibre Biometrics shows ads.

### Which is updated more often, Frontier X or Calibre Biometrics?

Frontier X ships an update every 2 weeks, and Calibre Biometrics every 4 weeks. Most recently, Frontier X was updated on November 7, 2026 and Calibre Biometrics on November 4, 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.*