# Tri vs Trajectory

The clearest difference is update cadence: Trajectory at fortnightly against Tri's every 12 months. Tri's advantage is iOS requirement (15.6 vs 17.7.2). On price, ads, in-app purchases and device support there is nothing between them.

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

Tri ships an update every 12 months, Trajectory fortnightly. The most recent releases landed on October 3, 2026 and September 24, 2026 respectively.

## The numbers

| Metric | Tri | Trajectory |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/tri-func/id496807268/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | No | No |
| Ads | Yes | Yes |
| Update frequency | Every 12 months | **Fortnightly** |
| Monetization | Ad-supported | — |
| Size | 4 MB | 36 MB |
| Requires iOS | **15.6** | 17.7.2 |
| Devices | **iPhone, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Thirdware.jp](https://appshunter.io/developer/464228680) | [Hideaki Uchikoshi](https://appshunter.io/developer/1559575002) |

## What reviewers say

### Tri

[App page](https://appshunter.io/ios/app/tri-func/id496807268)

This utility app provides the formula and value for calculating triangle properties. It's designed for quick access to mathematical formulas related to triangles.

**Highlights:** Triangle formula display, Value calculation, Quick access utility, Mathematical formulas

**Features:** 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 Tri free?

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

### Is Trajectory free?

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

### Do Tri or Trajectory have ads?

Both Tri and Trajectory show ads.

### Which is updated more often, Tri or Trajectory?

Tri ships an update every 12 months, and Trajectory fortnightly. Most recently, Tri was updated on October 3, 2026 and Trajectory on September 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.*