# CFS Tracker vs PEM Diary

The clearest difference is in-app purchases: PEM Diary at none against CFS Tracker's 16. PEM Diary also leads on update cadence (every 3 months vs every 8 months). CFS Tracker's advantage is device support (4 vs 2). On price, ads and iOS requirement there is nothing between them.

Both are free to download. CFS Tracker sells 16 in-app purchases, starting at $4.95 per month. PEM Diary asks for nothing beyond the download.

CFS Tracker ships an update every 8 months, PEM Diary every 3 months. The most recent releases landed on September 9, 2026 and September 10, 2026 respectively.

## The numbers

| Metric | CFS Tracker | PEM Diary |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[3.0 (2 ratings)](https://appshunter.io/ios/app/cfs-tracker/id6743564981/reviews)** | — |
| Number of ratings | **2** | — |
| Positive reviews | — | 50.0% of reviews |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 8 months | **Every 3 months** |
| Monetization | Free with in-app purchases | **Free** |
| Size | 219 MB | 92 MB |
| Requires iOS | 15.5 | **15.1** |
| Devices | **iPhone, iPad, iPod, Apple Watch** | iPhone, iPod |
| Age rating | 4+ | 17+ |
| Developer | [Clarity Digital Therapeutics Inc](https://appshunter.io/developer/1721663167) | [Add Jam](https://appshunter.io/developer/1075812699) |

## What reviewers say

### CFS Tracker

[App page](https://appshunter.io/ios/app/cfs-tracker/id6743564981)

This app helps individuals manage energy-limiting chronic illnesses by tracking symptoms, pacing, medications, and daily activities. It provides insights into patterns and trends to better understand health and communicate with healthcare providers.

**Highlights:** Log diverse symptoms including fatigue and brain fog, Track medications, supplements, and treatments, Record activity, rest, sleep, and nutrition, Customize tracking for personal health patterns, Set reminders for health routines, Monitor post-exertional malaise (PEM) and crashes, Review symptom trends with charts and summaries

**Features:** macOS Compatibility, Siri integration, Apple Watch app, iMessage stickers, Vision Pro support

**In-app purchases (16)**

| Purchase | Price | Billing |
| --- | --- | --- |
| flex pass | $4.95 | per month |
| easy pass | $5.99 | per 7 days |
| flex pass | $8.99 | per month |
| carey ai max | $19.99 | per month |
| yearly access | $19.99 | per year |
| smart pass | $24.99 | per year |
| carey ai ultra | $29.99 | per month |
| plus | $29.99 | per year |
| limited discount | $29.99 | per year |
| Premium Yearly | $34.99 | per year |
| yearly access | $39.99 | per year |
| Extended Trial | $39.99 | per year |
| 7-Day Trial | $49.99 | per year |
| store credit | $1.99 | one-time |
| carey ai credits | $8.99 | one-time |
| lifetime upgrade | $99.99 | one-time |


### PEM Diary

[App page](https://appshunter.io/ios/app/pem-diary-mecfs-crash-log/id6743624638)

This app helps individuals manage post-exertional malaise (PEM) by logging crashes, tracking severity, symptoms, and duration. It provides insights into patterns and creates a shareable record for personal reference or healthcare discussions.

**Highlights:** Log PEM crashes with dates, Track severity and symptoms, Add contextual notes, View trends on timeline/dashboard, 100% private local storage, Export data as CSV

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is CFS Tracker free?

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

### Is PEM Diary free?

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

### Do CFS Tracker or PEM Diary have ads?

Neither CFS Tracker nor PEM Diary shows ads.

### Which is updated more often, CFS Tracker or PEM Diary?

CFS Tracker ships an update every 8 months, and PEM Diary every 3 months. Most recently, CFS Tracker was updated on September 9, 2026 and PEM Diary on September 10, 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.*