# Walter Machining Calculator vs O

The clearest difference is rating: O at 3.8 against Walter Machining Calculator's 3.0. O also leads on update cadence (every 3 months vs every 19 months) and review sentiment (83% vs 63%). On price, ratings volume, 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.

O holds the better App Store score, 3.8 against 3.0. Both are backed by a comparable volume of ratings — 5 and 5 respectively. Written reviews point the same way: 63% of Walter Machining Calculator's written reviews are positive against 83% of O's.

Walter Machining Calculator ships an update every 19 months, O every 3 months. Both last shipped on October 23, 2026.

## The numbers

| Metric | Walter Machining Calculator | O |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [3.0 (5 ratings)](https://appshunter.io/ios/app/walter-machining-calculator/id423564212/reviews) | **[3.8 (5 ratings)](https://appshunter.io/ios/app/o-ring/id485346224/reviews)** |
| Number of ratings | 5 | 5 |
| Positive reviews | 62.9% of reviews | **83.3% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 19 months | **Every 3 months** |
| Monetization | Free | Free |
| Size | 95 MB | 26 MB |
| Requires iOS | 18.0 | **12.1** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 12+ |
| Developer | [Walter-AG](https://appshunter.io/developer/423564215) | [Trelleborg Sealing Solutions](https://appshunter.io/developer/396863758) |

## What reviewers say

### Walter Machining Calculator

[App page](https://appshunter.io/ios/app/walter-machining-calculator/id423564212)

Calculate machining time, power, torque, and cutting force for various operations. Compare existing tools with new ones to project potential savings.

**Highlights:** Calculate machining time, power, and torque, Determine cutting force and metal removal rate, Support for milling, drilling, boring, turning, and grooving, Thread tapping, forming, and milling calculations, Material selection for calculations, Savings calculator for tool comparison

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

**In-app purchases:** none


### 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


## Frequently asked questions

### Is Walter Machining Calculator free?

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

### Is O free?

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

### Which has better reviews, Walter Machining Calculator or O?

O is rated higher. Walter Machining Calculator averages 3.0 out of 5 from 5 ratings, while O averages 3.8 from 5 ratings.

### Do Walter Machining Calculator or O have ads?

Neither Walter Machining Calculator nor O shows ads.

### Which is updated more often, Walter Machining Calculator or O?

Walter Machining Calculator ships an update every 19 months, and O every 3 months. Most recently, Walter Machining Calculator was updated on October 23, 2026 and O on October 23, 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.*