# One Calendar vs PLN Open

The clearest difference is in-app purchases: PLN Open at none against One Calendar's 1. PLN Open also leads on update cadence (every 3 days vs fortnightly). On price, ads, device support and iOS requirement there is nothing between them.

Both are free to download. One Calendar sells 1 one-off in-app purchase. PLN Open asks for nothing beyond the download.

One Calendar ships an update fortnightly, PLN Open every 3 days. The most recent releases landed on October 26, 2026 and October 15, 2026 respectively.

## The numbers

| Metric | One Calendar | PLN Open |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.8 (21K ratings)](https://appshunter.io/ios/app/one-calendar/id1238379385/reviews)** | — |
| Number of ratings | **21K** | — |
| Positive reviews | 80.7% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Fortnightly | **Every 3 days** |
| Monetization | Free with in-app purchases | — |
| Size | 89 MB | 21 MB |
| Requires iOS | 15.0 | 15.0 |
| Devices | **iPhone, iPad, iPod, Mac** | iPhone, iPad, iPod |
| Age rating | 12+ | 4+ |
| Developer | [Code Spark](https://appshunter.io/developer/1238379384) | [Ministero delle Infrastrutture e dei Trasporti](https://appshunter.io/developer/417705374) |

## What reviewers say

### One Calendar

[App page](https://appshunter.io/ios/app/one-calendar/id1238379385)

Consolidate all your digital calendars into a single, easy-to-read view. Manage appointments, events, and birthdays from various providers like Google, Outlook, iCloud, and more, all within one application.

**Highlights:** Integrates multiple calendar providers, Easy-to-read overview, Manage appointments and events, View birthdays, Cross-platform availability

**Features:** Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| OneCalendar premium | $5.99 | one-time |

**What reviewers like**

- 🚀 Easy to use
- 👍 Clean and simple interface
- 👍 Integrates multiple calendars
- 🚀 Syncs across devices
- 👍 Customizable colors and themes

**What reviewers complain about**

- 🐛 Syncing issues
- 🐛 Bugs and glitches
- 🔒 Lacks security features
- 🔋 Drains battery
- 👎 Restrictive features in free version

**Reported bugs**

- Sync errors
- Unresponsive buttons
- Incorrect time zone display
- Duplicate events
- Inability to delete future occurrences of recurring events

**Requested features**

- Multiple reminders for events
- Ability to edit recurring events
- Option to change event calendar after creation
- Printing support
- More customization options


### PLN Open

[App page](https://appshunter.io/ios/app/pln-open/id6776702586)

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

**In-app purchases:** none


## Frequently asked questions

### Is One Calendar free?

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

### Is PLN Open free?

PLN Open is free to download, with no in-app purchases.

### Do One Calendar or PLN Open have ads?

Neither One Calendar nor PLN Open shows ads.

### Which is updated more often, One Calendar or PLN Open?

One Calendar ships an update fortnightly, and PLN Open every 3 days. Most recently, One Calendar was updated on October 26, 2026 and PLN Open on October 15, 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.*