# O vs MechTab

The clearest difference is rating: MechTab at 4.1 against O's 3.8. MechTab also leads on ratings volume (16 vs 5). O's advantage is update cadence (every 3 months vs every 9 months) and iOS requirement (12.1 vs 15.0). On price, review sentiment, ads and in-app purchases there is nothing between them.

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

MechTab holds the better App Store score, 4.1 against 3.8. Both are backed by a comparable volume of ratings — 5 and 16 respectively. Written reviews point the same way: 83% of O's written reviews are positive against 89% of MechTab's.

O ships an update every 3 months, MechTab every 9 months. The most recent releases landed on June 4, 2026 and September 15, 2026 respectively.

## The numbers

| Metric | O | MechTab |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [3.8 (5 ratings)](https://appshunter.io/ios/app/o-ring/id485346224/reviews) | **[4.1 (16 ratings)](https://appshunter.io/ios/app/mechtab/id553201101/reviews)** |
| Number of ratings | 5 | **16** |
| Positive reviews | 83.3% of reviews | **88.6% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 3 months** | Every 9 months |
| Monetization | Free | Free |
| Size | 26 MB | 9 MB |
| Requires iOS | **12.1** | 15.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 12+ | 4+ |
| Developer | [Trelleborg Sealing Solutions](https://appshunter.io/developer/396863758) | [Werder AG](https://appshunter.io/developer/553201104) |

## What reviewers say

### O

[App page](https://appshunter.io/ios/app/o-ring/id485346224)

This app helps users calculate O-Ring dimensions and find compatible materials for their applications. It provides recommendations based on ISO standards and supports both metric and inch measurements.

**Highlights:** O-Ring housing calculation, O-Ring size recommendations by ISO standard, Quick search by national/international standards, O-Ring tolerance calculation, Metric and inch unit switching, Chemical compatibility check, Integration of Trelleborg Sealing Solutions Videos

**Features:** macOS Compatibility

**In-app purchases:** none


### MechTab

[App page](https://appshunter.io/ios/app/mechtab/id553201101)

This app offers a comprehensive set of tools for mechanics, providing essential data on tolerances, threads, cutting speeds, wrench sizes, and roughness. It also includes calculators for material weight, triangle properties, and trowalisation.

**Highlights:** ISO-Tolerance data (holes and shafts), Thread specifications, Cutting data calculations, Wrench size conversions, Roughness parameters, Material weight calculator, Triangle property calculator

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

**In-app purchases:** none


## Frequently asked questions

### Is O free?

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

### Is MechTab free?

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

### Which has better reviews, O or MechTab?

MechTab is rated higher. O averages 3.8 out of 5 from 5 ratings, while MechTab averages 4.1 from 16 ratings.

### Do O or MechTab have ads?

Neither O nor MechTab shows ads.

### Which is updated more often, O or MechTab?

O ships an update every 3 months, and MechTab every 9 months. Most recently, O was updated on June 4, 2026 and MechTab on September 15, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*