# 一発修正君 vs Triangle3

The clearest difference is price: 一発修正君 at Free against Triangle3's $3.99. 一発修正君 also leads on iOS requirement (13.1 vs 15.0). Triangle3's advantage is update cadence (every 5 weeks vs every 12 months). On ads, in-app purchases and device support there is nothing between them.

一発修正君 is free to download; Triangle3 costs $3.99 up front. Neither carries in-app purchases, so what you see is what you pay.

一発修正君 ships an update every 12 months, Triangle3 every 5 weeks. The most recent releases landed on September 17, 2026 and September 26, 2026 respectively.

## The numbers

| Metric | 一発修正君 | Triangle3 |
| --- | --- | --- |
| Price | **Free** | $3.99 |
| Positive reviews | — | 40.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 12 months | **Every 5 weeks** |
| Monetization | — | Paid |
| Size | 6 MB | 7 MB |
| Requires iOS | **13.1** | 15.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [yoshida kogyo,y.k.](https://appshunter.io/developer/1076229459) | [ryo sasaki](https://appshunter.io/developer/318552526) |

## What reviewers say

### 一発修正君

[App page](https://appshunter.io/ios/app/id1076229460)

**Features:** Vision Pro support

**In-app purchases:** none


### Triangle3

[App page](https://appshunter.io/ios/app/triangle3/id1643788233)

This app provides advanced calculation tools for field work, specializing in right and unequal triangles. It supports complex shapes like cones, pipes, and screw wings, with AR visualization for floor plans. It also includes standard calculator functions and memory features.

**Highlights:** Right and unequal triangle calculations, Complex shape development (cones, pipes, etc.), Augmented Reality (AR) floor plan visualization, Standard calculator functions with memory, Trigonometric and cosine theorem calculations, PCD and screw wing calculations

**Features:** Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is 一発修正君 free?

一発修正君 is free to download, with no in-app purchases.

### Is Triangle3 free?

Triangle3 costs $3.99, with no in-app purchases.

### Do 一発修正君 or Triangle3 have ads?

Neither 一発修正君 nor Triangle3 shows ads.

### Which is updated more often, 一発修正君 or Triangle3?

一発修正君 ships an update every 12 months, and Triangle3 every 5 weeks. Most recently, 一発修正君 was updated on September 17, 2026 and Triangle3 on September 26, 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.*