# O2 Duration vs FLT DIR

The clearest difference is review sentiment: FLT DIR at 90% against O2 Duration's 0%. FLT DIR also leads on price (Free vs $2.99) and rating (4.8 vs 1.0). O2 Duration's advantage is iOS requirement (7.0 vs 17.0). On ads, in-app purchases and device support there is nothing between them.

FLT DIR is free to download; O2 Duration costs $2.99 up front. Neither carries in-app purchases, so what you see is what you pay.

FLT DIR holds the better App Store score, 4.8 against 1.0. That said, the two scores are not equally well evidenced: FLT DIR has 39 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 0% of O2 Duration's written reviews are positive against 90% of FLT DIR's.

O2 Duration ships an update every 15 months, FLT DIR every 2 weeks. The most recent releases landed on October 15, 2026 and October 24, 2026 respectively.

## The numbers

| Metric | O2 Duration | FLT DIR |
| --- | --- | --- |
| Price | $2.99 | **Free** |
| Rating | [1.0 (1 ratings)](https://appshunter.io/ios/app/o2-duration/id556420187/reviews) | **[4.8 (39 ratings)](https://appshunter.io/ios/app/flt-dir-flight-director/id6753682379/reviews)** |
| Number of ratings | 1 | **39** |
| Positive reviews | 0.0% of reviews | **90.0% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 15 months | **Every 2 weeks** |
| Monetization | Paid | **Free** |
| Size | 1 MB | 17 MB |
| Requires iOS | **7.0** | 17.0 |
| Devices | **iPhone, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Advanced Aviation LLC](https://appshunter.io/developer/540245667) | [Flt Dir LLC](https://appshunter.io/developer/1844371790) |

## What reviewers say

### O2 Duration

[App page](https://appshunter.io/ios/app/o2-duration/id556420187)

Calculate the approximate remaining oxygen in portable cylinders. Select your tank size, input current pressure and desired flow rate to see duration in minutes. Features a timer with alerts for low pressure.

**Highlights:** Oxygen cylinder duration calculation, Supports multiple cylinder sizes (A, B, D, E, G, H, K, M), Input current tank pressure, Input desired flow rate, Displays duration in minutes, Running timer with remaining time, Low pressure alerts (500lbs and 0lbs)

**Features:** macOS Compatibility

**In-app purchases:** none


### FLT DIR

[App page](https://appshunter.io/ios/app/flt-dir-flight-director/id6753682379)

This app helps pilots, flight schools, and aircraft owners manage all aspects of aircraft operations. It offers comprehensive flight logging, smart scheduling, advanced maintenance tracking, and team collaboration features for efficient fleet management.

**Highlights:** Comprehensive flight logging, Smart scheduling & calendar, Advanced maintenance tracking, Team collaboration, Fleet management, FlightAware integration

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

**In-app purchases:** none


## Frequently asked questions

### Is O2 Duration free?

O2 Duration costs $2.99, with no in-app purchases.

### Is FLT DIR free?

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

### Which has better reviews, O2 Duration or FLT DIR?

FLT DIR is rated higher. O2 Duration averages 1.0 out of 5 from 1 ratings, while FLT DIR averages 4.8 from 39 ratings.

### Do O2 Duration or FLT DIR have ads?

Neither O2 Duration nor FLT DIR shows ads.

### Which is updated more often, O2 Duration or FLT DIR?

O2 Duration ships an update every 15 months, and FLT DIR every 2 weeks. Most recently, O2 Duration was updated on October 15, 2026 and FLT DIR 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.*