# Bolt Length vs Thread Calculator

The clearest difference is rating: Thread Calculator at 4.3 against Bolt Length's 3.0. Thread Calculator also leads on in-app purchases (none vs 1) and ratings volume (13 vs 2). On price, review sentiment, update cadence and ads there is nothing between them.

Both are free to download. Bolt Length sells 1 one-off in-app purchase. Thread Calculator asks for nothing beyond the download.

Thread Calculator holds the better App Store score, 4.3 against 3.0. That said, the two scores are not equally well evidenced: Thread Calculator has 13 ratings behind it against 2, so its average is the more settled of the two. Written reviews split almost evenly too, at 33% and 33% positive.

Bolt Length ships an update every 20 months, Thread Calculator every 18 months. The most recent releases landed on October 8, 2026 and October 13, 2026 respectively.

## The numbers

| Metric | Bolt Length | Thread Calculator |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [3.0 (2 ratings)](https://appshunter.io/ios/app/bolt-length-nominal-length/id1042345193/reviews) | **[4.3 (13 ratings)](https://appshunter.io/ios/app/thread-calculator/id1559560290/reviews)** |
| Number of ratings | 2 | **13** |
| Positive reviews | 33.3% of reviews | 33.3% of reviews |
| In-app purchases | Yes | **No** |
| Ads | Yes | Yes |
| Update frequency | Every 20 months | **Every 18 months** |
| Monetization | Free with in-app purchases | **Ad-supported** |
| Size | 6 MB | 25 MB |
| Requires iOS | **14.0** | 15.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [mitsunori oishi](https://appshunter.io/developer/905649994) | [GSR Gustav Stursberg GmbH](https://appshunter.io/developer/1559560292) |

## 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 |


### Thread Calculator

[App page](https://appshunter.io/ios/app/thread-calculator/id1559560290)

This app provides a quick and easy way to calculate thread dimensions for various units, including tap hole sizes and bolt specifications. It helps metalworkers find precise measurements for internal and external threads without consulting tables.

**Highlights:** Thread cutting calculator for multiple units, Cold forming calculator, Thread repair calculator, Tap hole and bolt diameter calculation, Saves time compared to tables

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Bolt Length free?

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

### Is Thread Calculator free?

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

### Which has better reviews, Bolt Length or Thread Calculator?

Thread Calculator is rated higher. Bolt Length averages 3.0 out of 5 from 2 ratings, while Thread Calculator averages 4.3 from 13 ratings.

### Do Bolt Length or Thread Calculator have ads?

Both Bolt Length and Thread Calculator show ads.

### Which is updated more often, Bolt Length or Thread Calculator?

Bolt Length ships an update every 20 months, and Thread Calculator every 18 months. Most recently, Bolt Length was updated on October 8, 2026 and Thread Calculator on October 13, 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.*