# Tuta Calendar vs Flow Interval

The clearest difference is update cadence: Tuta Calendar at weekly against Flow Interval's every 3 months. Tuta Calendar also leads on iOS requirement (16.0 vs 26.0). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Tuta Calendar sells 4 in-app purchases, starting at $3.99 per month and Flow Interval sells 3 one-off in-app purchases. Whichever you choose, the download price is not the number that matters.

Tuta Calendar ships an update weekly, Flow Interval every 3 months. The most recent releases landed on October 27, 2026 and October 7, 2026 respectively.

## The numbers

| Metric | Tuta Calendar | Flow Interval |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.6 (163 ratings)](https://appshunter.io/ios/app/tuta-calendar-secure-planner/id6657977811/reviews)** | — |
| Number of ratings | **163** | — |
| Positive reviews | 56.7% of reviews | — |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | **Weekly** | Every 3 months |
| Monetization | Freemium | — |
| Size | 45 MB | 1 MB |
| Requires iOS | **16.0** | 26.0 |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Tutao GmbH](https://appshunter.io/developer/922429608) | [Takumi Kanaya](https://appshunter.io/developer/1852755878) |

## What reviewers say

### Tuta Calendar

[App page](https://appshunter.io/ios/app/tuta-calendar-secure-planner/id6657977811)

This secure calendar app offers end-to-end encryption to protect your events and reminders. It features a user-friendly interface, cross-device syncing, and smart reminders, with a free plan and optional premium upgrades.

**Highlights:** Quantum-safe end-to-end encryption, Zero tracking and zero-knowledge architecture, Secure event sharing, Cross-device syncing, Multiple calendar views, Smart event reminders, Offline access

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Revolutionary (Monthly) | $3.99 | per month |
| Legend (Monthly) | $9.99 | per month |
| Revolutionary (Yearly) | $39.99 | per year |
| Legend (Yearly) | $99.99 | per year |

**What reviewers like**

- 🔒 Privacy and security focused
- 👍 Streamlined and minimalist design
- 🔄 Calendar subscriptions work well
- ✨ Good color schemes and views
- ✅ Private alternative to big tech

**What reviewers complain about**

- 🐛 Frequent crashes and bugs
- ⚠️ Requires account/login
- 📅 Widget not working/limited
- ❌ No watch app support
- ⏳ Slow loading/reloading events

**Reported bugs**

- App crashes frequently
- Widget is not working or is blank
- Calendar events not saving or changes not saving
- App logs out automatically and shows invalid credentials
- Double reminders for appointments

**Requested features**

- App for the Watch
- Icon shows current date
- Ability to see holidays marked
- Import from Apple calendar
- Adjustable app opening view (e.g., month view)


### Flow Interval

[App page](https://appshunter.io/ios/app/flow-interval/id6757172069)

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Small Tip | $0.99 | one-time |
| Medium Tip | $3.99 | one-time |
| Large Tip | $8.99 | one-time |


## Frequently asked questions

### Is Tuta Calendar free?

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

### Is Flow Interval free?

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

### Do Tuta Calendar or Flow Interval have ads?

Neither Tuta Calendar nor Flow Interval shows ads.

### Which is updated more often, Tuta Calendar or Flow Interval?

Tuta Calendar ships an update weekly, and Flow Interval every 3 months. Most recently, Tuta Calendar was updated on October 27, 2026 and Flow Interval on October 7, 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.*