# Relativity Calendar vs Datum

The clearest difference is price: Relativity Calendar at Free against Datum's $1.99. Relativity Calendar also leads on update cadence (every 2 months vs every 3 months) and iOS requirement (15.0 vs 17.6). Datum's advantage is device support (5 vs 3). On review sentiment, ads and in-app purchases there is nothing between them.

Relativity Calendar is free to download; Datum costs $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Relativity Calendar ships an update every 2 months, Datum every 3 months. The most recent releases landed on October 25, 2026 and October 24, 2026 respectively.

## The numbers

| Metric | Relativity Calendar | Datum |
| --- | --- | --- |
| Price | **Free** | $1.99 |
| Rating | **[4.9 (17 ratings)](https://appshunter.io/ios/app/relativity-calendar/id1481494405/reviews)** | — |
| Number of ratings | **17** | — |
| Positive reviews | 100.0% of reviews | 100.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 2 months** | Every 3 months |
| Monetization | **Free** | Paid |
| Size | 3 MB | 15 MB |
| Requires iOS | **15.0** | 17.6 |
| Devices | iPhone, iPod, Apple Watch | **iPhone, iPad, Mac, Apple Watch, Vision Pro** |
| Age rating | 4+ | 4+ |
| Developer | [Jonathan Cole](https://appshunter.io/developer/1093735229) | [Michael Lindinger](https://appshunter.io/developer/1431086653) |

## What reviewers say

### Relativity Calendar

[App page](https://appshunter.io/ios/app/relativity-calendar/id1481494405)

This app redefines how you view dates by allowing you to express any day relative to any month. See custom dates like 'May 32nd' or 'March 93rd' at a glance. It offers home screen widgets and Apple Watch complications for easy access.

**Highlights:** Express dates relative to any month, Home screen widgets with color customization, Apple Watch complications, iOS 16 Lock Screen widgets, Track custom dates and holidays

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

**In-app purchases:** none


### Datum

[App page](https://appshunter.io/ios/app/datum-calendar/id1552646317)

A minimalist calendar application designed for Apple devices, offering a clean interface and customizable widgets for iOS, macOS, and watchOS. View upcoming events, daily schedules, and monthly overviews directly from your home screen or watch face.

**Highlights:** Minimalist calendar interface, Lockscreen widgets for iOS, Event display widgets, Calendar widgets with event marks, watchOS calendar and complications, Support for iPhone, iPad, Mac, and Apple Watch

**Features:** Apple Watch app

**In-app purchases:** none


## Frequently asked questions

### Is Relativity Calendar free?

Relativity Calendar is free to download, with no in-app purchases.

### Is Datum free?

Datum costs $1.99, with no in-app purchases.

### Do Relativity Calendar or Datum have ads?

Neither Relativity Calendar nor Datum shows ads.

### Which is updated more often, Relativity Calendar or Datum?

Relativity Calendar ships an update every 2 months, and Datum every 3 months. Most recently, Relativity Calendar was updated on October 25, 2026 and Datum on October 24, 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.*