# TruAirspeed

> Calculates true airspeed, pressure altitude, density altitude, and Mach number for pilots. (iPhone/iPad app by James Petty.)

- Source: https://appshunter.io/ios/app/truairspeed/id855269892 (this page in markdown: same URL + `.md`)
- Developer: [James Petty](https://appshunter.io/developer/603661046)
- Category: Utilities
- Price: Free
- Rating: 4.10/5 from 8 App Store ratings · 7 written reviews indexed
- Age rating: 4+
- Requires: iOS 15.6 · 8 MB
- Languages: American English
- Released: 2014-04-14
- Data updated: 2026-06-02
- Monetization: free
- User reviews in markdown: https://appshunter.io/ios/app/truairspeed/id855269892/reviews.md

## What is TruAirspeed?

TruAirspeed is a True Airspeed Calculator for the iPhone and iPad.  It's a bit different from other true airspeed calculators, in which the pressure altitude is an input.  This requires resetting the altimeter to the standard sea level pressure of 29.92"Hg to read the pressure altitude.  With TruAirspeed, you input the indicated altitude and the Kollsman window's pressure setting — the app then calculates the pressure altitude, density altitude, true airspeed and mach number for you.

The calculations involved take full account of compressibility effects, but not shock waves, so it's limited to subsonic, non-transonic flight only.

You have a choice of units for inputs and results, and you may choose either a calculator-style keypad (top row: 7-8-9) or a telephone-style keypad (top row: 1-2-3).  You may also set a correction factor for your bird's airspeed indicator/pitot-static system, if you know it (mine is 0.95).

## Key features

- True airspeed calculation
- Pressure and density altitude calculation
- Mach number calculation
- Compressibility effects accounted for
- Choice of input/result units
- Calculator or telephone keypad options
- Airspeed indicator correction factor

## Recent user reviews (7 of 7)

All indexed reviews: https://appshunter.io/ios/app/truairspeed/id855269892/reviews.md

### 4/5 — How do u change to mph

*2024-09-05*

I can’t find how to change knots to miles per hour which my airspeed indicator is calibrated in?

### 5/5 — Well Done

*2024-01-01*

Thank you.   Both of your apps are absolutely perfect.  Thank you.

### 5/5 — Works as stated. Generous contributor to the flight testing and experimental community.

*2023-05-13*

Another useful offering by Mr. Petty. Thank you sir. I’m enjoying tinkering with Benchmark too. As for the one user saying there is no way to change units; there is. Tap the little “i” in the corner and drill down. As for the other claiming the app is inaccurate, if you mix up C and F, you get a big error (10 knots on a sample I just did).

### 1/5 — Incorrect compared to other calculators

*2022-01-30*

Off by between 5-10 kts.  Not reliable

### 3/5 — No way to choose between F and C?

*2021-08-22*

Is there really no way to change between Celsius and Fahrenheit? That makes it so you need another app to convert temperature. Am I missing something? This seems like a major oversight.

### 5/5 — Simple but lacking unit selection

*2020-07-11*

Simple app very easy to use. That is exactly what I was looking for.

### 5/5 — Excellent

*2016-06-15*

A great tool - thanks :-)

## Frequently asked questions about TruAirspeed

### What is TruAirspeed used for?

TruAirspeed is a utility designed to calculate true airspeed, pressure altitude, density altitude, and Mach number. It is particularly useful for pilots who need to understand these critical flight parameters.

### How accurate are TruAirspeed's calculations?

The calculations in TruAirspeed take full account of compressibility effects for subsonic, non-transonic flight. It does not account for shock waves, limiting its use to these flight regimes.

### Can I customize the units in TruAirspeed?

Yes, TruAirspeed offers a choice of units for both inputs and results. This allows users to tailor the app to their specific preferences and operational needs.

### Does TruAirspeed have ads?

No, TruAirspeed does not contain advertisements. It is a free application that provides its core functionality without interruption.

### What devices is TruAirspeed compatible with?

TruAirspeed is available for iPhone, iPad, and iPod touch devices. It is designed to run on Apple's mobile operating systems.

### How often is TruAirspeed updated?

The latest version of TruAirspeed is 2.1, which was last updated on July 8, 2025. This indicates active development and maintenance of the application.

### What is the age rating for TruAirspeed?

TruAirspeed has an age rating of 4+. This suggests that the content and functionality of the app are considered appropriate for users aged four and older.

### Can I input a correction factor for my airspeed indicator in TruAirspeed?

Yes, TruAirspeed allows you to set a correction factor for your aircraft's airspeed indicator or pitot-static system if you know it. This helps to improve the accuracy of the calculations.

## Version history (last 5 releases)

### 2.1 — 2025-07-08

Due to changes in the iPad coding environment, I've had to make some major "under the hood" changes to TruAirspeed. While its appearance on iPads has changed a bit, features and functionality are unaffected.  Following a user's suggestion, I've also enlarged the main screen layout on iPads for better usability when flying.
I've also updated the app for operation under iOS18 and iPadOS18, and for compatibility with all current iPhone and iPad models.

### 2.0 — 2024-06-25

TruAirspeed can now be used in landscape mode on all iPhone models (except the 1st generation iPhone SE).
I've updated the app for operation under iOS17 and iPadOS17, and for compatibility with all current iPhone and iPad models.
I've fixed a bug with the ASI correction factor.
I've also done a significant amount of code cleanup.
Otherwise, features and functionality are unchanged.

### 1.4 — 2022-06-17

In Version 1.4, TruAirspeed has been updated for operation under iOS15 and iPadOS15, and for compatibility with all current iPhone and iPad models.  I have also added my Privacy Policy to the Info screen.  Otherwise, appearance, features and functionality are unchanged.

### 1.3 — 2020-06-30

In Version 1.3, TruAirspeed has been updated for operation under iOS13 and iPadOS13, including Dark mode.  Also, a few bug fixes and minor aesthetic changes have been made

### 1.2 — 2018-03-18

Version 1.2 has a number of notable improvements:
−  The app now calculates and displays the mach number as well as the true airspeed.
−  TruAirspeed is now a universal app (for those, like me, who also use this app on their iPads).  The iPad version supports both portrait and landscape orientations, but is full screen only.
−  The input keypad now plays nicely with touch cursor positioning and range selection.
−  The iPad version of the input keypad also has cursor keys and a \"restore\" key which restores the input field to it's initial value at the start of editing.
−  The input keypad background now has a more aesthetically pleasing appearance.
−  There are also many "under-the-hood" improvements.

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## More apps by James Petty

- [Falco W&B](https://appshunter.io/ios/app/falco-w-and-b/id603661043)
- [AircraftPower](https://appshunter.io/ios/app/aircraftpower/id718023187)
- [AircraftPower S](https://appshunter.io/ios/app/aircraftpower-s/id1671252596)

All apps by James Petty: https://appshunter.io/developer/603661046

## Related topics

[mach 1 integration](https://appshunter.io/ios/topics/mach-1-integration)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-02.*