# O vs Fit Tolerance ANSI

The clearest difference is ads: O at none against Fit Tolerance ANSI's shown. O also leads on monetization model (free vs ad-supported). Fit Tolerance ANSI's advantage is device support (3 vs 1). On price, rating, ratings volume and update cadence there is nothing between them.

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

On the App Store both sit at effectively the same score — 5.0 for O against 5.0 for Fit Tolerance ANSI. Both are backed by a comparable volume of ratings — 1 and 2 respectively.

O ships an update every 11 months, Fit Tolerance ANSI every 9 months. The most recent releases landed on November 2, 2026 and November 3, 2026 respectively.

## The numbers

| Metric | O | Fit Tolerance ANSI |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [5.0 (1 ratings)](https://appshunter.io/ios/app/o-ring-master/id1072051820/reviews) | [5.0 (2 ratings)](https://appshunter.io/ios/app/fit-tolerance-ansi/id1294112198/reviews) |
| Number of ratings | 1 | **2** |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | No | No |
| Ads | **No** | Yes |
| Update frequency | Every 11 months | **Every 9 months** |
| Monetization | **Free** | Ad-supported |
| Size | 47 MB | 51 MB |
| Requires iOS | 16.0 | **15.0** |
| Devices | iPhone | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [GE MAO RUBBER INDUSTRIAL CO., LTD.](https://appshunter.io/developer/1078558543) | [Yasar Yucel Yesilbag](https://appshunter.io/developer/1251895011) |

## What reviewers say

### O

[App page](https://appshunter.io/ios/app/o-ring-master/id1072051820)

This app provides a comprehensive offline tool for selecting standard rubber seal sizes, including O-Rings, X-Rings, and Back-Up Rings. It offers dimension searches, housing calculations for various sealing applications, and supports multiple international standards in both metric and imperial units.

**Highlights:** Offline standard rubber seal size selection, Search for O-Ring, X-Ring, and Back-Up Ring sizes, O-Ring housing calculations for sealing applications, Supports multiple international standards (AS568, METRIC, JIS, etc.), Metric and Imperial unit support, Substitutable O-Ring size suggestions

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

**In-app purchases:** none


### Fit Tolerance ANSI

[App page](https://appshunter.io/ios/app/fit-tolerance-ansi/id1294112198)

Calculate ANSI standard limits and fits for cylindrical parts like bearings and shafts. It supports various fit types based on inch units and provides a schematic representation of the fit. Ideal for engineers and designers working with precision components.

**Highlights:** ANSI standard limits and fits calculation, Supports inch units, Calculates tolerances for inner and outer features, Handles various fit types (RC, LC, LT, LN, FN), Schematic representation of fits, Applicable to non-threaded cylindrical parts

**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 Fit Tolerance ANSI free?

Fit Tolerance ANSI is free to download, with no in-app purchases.

### Which has better reviews, O or Fit Tolerance ANSI?

O and Fit Tolerance ANSI are both rated 5.0 out of 5 on the App Store, from 1 and 2 ratings respectively.

### Do O or Fit Tolerance ANSI have ads?

Fit Tolerance ANSI shows ads; O does not.

### Which is updated more often, O or Fit Tolerance ANSI?

O ships an update every 11 months, and Fit Tolerance ANSI every 9 months. Most recently, O was updated on November 2, 2026 and Fit Tolerance ANSI on November 3, 2026.

---

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