# Relativity Calendar vs Trajectory

The clearest difference is ads: Relativity Calendar at none against Trajectory's shown. Relativity Calendar also leads on device support (3 vs 1) and iOS requirement (15.0 vs 17.7.2). Trajectory's advantage is update cadence (fortnightly vs every 2 months). On price and in-app purchases there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Relativity Calendar ships an update every 2 months, Trajectory fortnightly. The most recent releases landed on September 28, 2026 and October 11, 2026 respectively.

## The numbers

| Metric | Relativity Calendar | Trajectory |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.9 (17 ratings)](https://appshunter.io/ios/app/relativity-calendar/id1481494405/reviews)** | — |
| Number of ratings | **17** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | No | No |
| Ads | **No** | Yes |
| Update frequency | Every 2 months | **Fortnightly** |
| Monetization | Free | — |
| Size | 3 MB | 36 MB |
| Requires iOS | **15.0** | 17.7.2 |
| Devices | **iPhone, iPod, Apple Watch** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Jonathan Cole](https://appshunter.io/developer/1093735229) | [Hideaki Uchikoshi](https://appshunter.io/developer/1559575002) |

## 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


### Trajectory

[App page](https://appshunter.io/ios/app/trajectory-detection/id6511212764)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Relativity Calendar free?

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

### Is Trajectory free?

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

### Do Relativity Calendar or Trajectory have ads?

Trajectory shows ads; Relativity Calendar does not.

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

Relativity Calendar ships an update every 2 months, and Trajectory fortnightly. Most recently, Relativity Calendar was updated on September 28, 2026 and Trajectory on October 11, 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.*