# Houji vs Bolt Length

The clearest difference is price: Bolt Length at Free against Houji's $1.99. Bolt Length also leads on device support (3 vs 1) and iOS requirement (14.0 vs 16.1). Houji's advantage is in-app purchases (none vs 1) and ads (none vs shown).

Bolt Length is free to download; Houji costs $1.99 up front. Bolt Length sells 1 one-off in-app purchase. Houji asks for nothing beyond the download.

Houji ships an update every 7 months, Bolt Length every 20 months. The most recent releases landed on November 1, 2026 and November 2, 2026 respectively.

## The numbers

| Metric | Houji | Bolt Length |
| --- | --- | --- |
| Price | $1.99 | **Free** |
| 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 |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | **Every 7 months** | Every 20 months |
| Monetization | — | Free with in-app purchases |
| Size | 4 MB | 6 MB |
| Requires iOS | 16.1 | **14.0** |
| Devices | iPhone | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [her0.jp](https://appshunter.io/developer/482918302) | [mitsunori oishi](https://appshunter.io/developer/905649994) |

## What reviewers say

### Houji

[App page](https://appshunter.io/ios/app/houji/id482918299)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### 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 |


## Frequently asked questions

### Is Houji free?

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

### Is Bolt Length free?

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

### Do Houji or Bolt Length have ads?

Bolt Length shows ads; Houji does not.

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

Houji ships an update every 7 months, and Bolt Length every 20 months. Most recently, Houji was updated on November 1, 2026 and Bolt Length on November 2, 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.*