# Caffeine Rhythm vs CalShift

The clearest difference is ads: CalShift at none against Caffeine Rhythm's shown. CalShift also leads on iOS requirement (13.0 vs 17.0). Caffeine Rhythm's advantage is update cadence (every 3 weeks vs every 3 months). On price, in-app purchases and device support there is nothing between them.

Both are free to download. Caffeine Rhythm sells 2 in-app purchases, starting at $1.99 per month and CalShift sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

Caffeine Rhythm ships an update every 3 weeks, CalShift every 3 months. The most recent releases landed on October 10, 2026 and October 13, 2026 respectively.

## The numbers

| Metric | Caffeine Rhythm | CalShift |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/caffeine-rhythm/id6756790180/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | Yes | Yes |
| Ads | Yes | **No** |
| Update frequency | **Every 3 weeks** | Every 3 months |
| Monetization | Freemium | — |
| Size | 23 MB | 30 MB |
| Requires iOS | 17.0 | **13.0** |
| Devices | **iPhone, iPad, Apple Watch** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Hatching Point LLC](https://appshunter.io/developer/1860158157) | [Zhihao Yang](https://appshunter.io/developer/1466209376) |

## What reviewers say

### Caffeine Rhythm

[App page](https://appshunter.io/ios/app/caffeine-rhythm/id6756790180)

Track your caffeine intake and understand its impact on your body. This app calculates your real-time caffeine levels and predicts when you'll be able to sleep, helping you optimize your daily consumption for better rest.

**Highlights:** Real-time caffeine decay tracking, Personalized half-life calculation, Sleep safety countdown, Coffee shop menu integration, Streak tracking and gamification, Apple Watch app with complications, Home Screen and Lock Screen widgets, HealthKit integration

**Features:** macOS Compatibility, Apple Watch app, Vision Pro support

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Monthly Premium | $1.99 | per month |
| Yearly Premium | $9.99 | per year |


### CalShift

[App page](https://appshunter.io/ios/app/calshift-shift-work-calendar/id6758676304)

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Unlock Shift Pro | $0.99 | one-time |


## Frequently asked questions

### Is Caffeine Rhythm free?

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

### Is CalShift free?

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

### Do Caffeine Rhythm or CalShift have ads?

Caffeine Rhythm shows ads; CalShift does not.

### Which is updated more often, Caffeine Rhythm or CalShift?

Caffeine Rhythm ships an update every 3 weeks, and CalShift every 3 months. Most recently, Caffeine Rhythm was updated on October 10, 2026 and CalShift on October 13, 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.*