# Area Volume Calculator vs O

The clearest difference is review sentiment: O at 100% against Area Volume Calculator's 44%. O also leads on rating (5.0 vs 4.1). Area Volume Calculator's advantage is ratings volume (14 vs 1) and device support (3 vs 1). On price, update cadence, 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, 5.0 against 4.1. That said, the two scores are not equally well evidenced: Area Volume Calculator has 14 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 44% of Area Volume Calculator's written reviews are positive against 100% of O's.

Area Volume Calculator ships an update every 6 months, O every 11 months. Both last shipped on October 24, 2026.

## The numbers

| Metric | Area Volume Calculator | O |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.1 (14 ratings)](https://appshunter.io/ios/app/area-volume-calculator/id1051276090/reviews) | **[5.0 (1 ratings)](https://appshunter.io/ios/app/o-ring-master/id1072051820/reviews)** |
| Number of ratings | **14** | 1 |
| Positive reviews | 44.4% of reviews | **100.0% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 6 months** | Every 11 months |
| Monetization | Free | Free |
| Size | 16 MB | 47 MB |
| Requires iOS | **11.0** | 16.0 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Trelleborg Sealing Solutions](https://appshunter.io/developer/396863758) | [GE MAO RUBBER INDUSTRIAL CO., LTD.](https://appshunter.io/developer/1078558543) |

## What reviewers say

### Area Volume Calculator

[App page](https://appshunter.io/ios/app/area-volume-calculator/id1051276090)

Easily calculate area, perimeter, volume, and weight for over 170 geometric shapes. Input measurements, select materials, and choose units for precise results. Includes shape definitions and formulas.

**Highlights:** 170+ geometric shapes, Calculate area, perimeter, volume, and weight, Material selection for weight calculation, Metric and Inch unit support, Shape definitions and formulas, Search and swipe navigation

**Features:** macOS Compatibility

**In-app purchases:** none


### 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


## Frequently asked questions

### Is Area Volume Calculator free?

Area Volume 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, Area Volume Calculator or O?

O is rated higher. Area Volume Calculator averages 4.1 out of 5 from 14 ratings, while O averages 5.0 from 1 ratings.

### Do Area Volume Calculator or O have ads?

Neither Area Volume Calculator nor O shows ads.

### Which is updated more often, Area Volume Calculator or O?

Area Volume Calculator ships an update every 6 months, and O every 11 months. Most recently, Area Volume Calculator was updated on October 24, 2026 and O on October 24, 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.*