# Bolt Length vs Triangle3

The clearest difference is price: Bolt Length at Free against Triangle3's $3.99. Triangle3's advantage is in-app purchases (none vs 1) and ads (none vs shown). On review sentiment, device support and iOS requirement there is nothing between them.

Bolt Length is free to download; Triangle3 costs $3.99 up front. Bolt Length sells 1 one-off in-app purchase. Triangle3 asks for nothing beyond the download.

Bolt Length ships an update every 20 months, Triangle3 every 5 weeks. The most recent releases landed on October 8, 2026 and October 17, 2026 respectively.

## The numbers

| Metric | Bolt Length | Triangle3 |
| --- | --- | --- |
| Price | **Free** | $3.99 |
| Rating | **[3.0 (2 ratings)](https://appshunter.io/ios/app/bolt-length-nominal-length/id1042345193/reviews)** | — |
| Number of ratings | **2** | — |
| Positive reviews | 33.3% of reviews | **40.0% of reviews** |
| In-app purchases | Yes | **No** |
| Ads | Yes | **No** |
| Update frequency | Every 20 months | **Every 5 weeks** |
| Monetization | **Free with in-app purchases** | Paid |
| Size | 6 MB | 7 MB |
| Requires iOS | **14.0** | 15.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [mitsunori oishi](https://appshunter.io/developer/905649994) | [ryo sasaki](https://appshunter.io/developer/318552526) |

## What reviewers say

### Bolt Length

[App page](https://appshunter.io/ios/app/bolt-length-nominal-length/id1042345193)

This application helps calculate the length of metric coarse screws based on Japanese Industrial Standards. It is designed for mechanical design purposes and should be used at the user's own risk.

**Highlights:** Metric coarse screw length calculation, Conforms to Japanese Industrial Standards (JIS), Designed for mechanical design, User risk disclaimer

**Features:** macOS Compatibility, Family Sharing

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Hide Ads | $1.99 | one-time |


### 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 Bolt Length free?

Bolt Length is free to download, with in-app purchases available.

### Is Triangle3 free?

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

### Do Bolt Length or Triangle3 have ads?

Bolt Length shows ads; Triangle3 does not.

### Which is updated more often, Bolt Length or Triangle3?

Bolt Length ships an update every 20 months, and Triangle3 every 5 weeks. Most recently, Bolt Length was updated on October 8, 2026 and Triangle3 on October 17, 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.*