Rocket Calculator

I currently don’t have the time or resources to maintain Rocket Calculator. It will remain on the app store for those who have purchased it, but I don’t plan to continue updating the software. Thank you all who have purchased and used this product.

I have decided to open-source the code base of the most recent version. The address is

The current version in the app store is free for as long as it remains there. I will not renew my Apple developer account, which should expire in April/May 2017. After that it’ll probably be pulled, but those who’ve purchased will still be able to download it after that.


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Version 1.5.5 submitted to Appstore

This version of Rocket Calculator includes the missing Aerotech single use D21 and E15 motors. I also added the air frame dimensions for Aerotech, PML, Always Ready Rocketry(Blue Tube) and Madcow body tubes. Lately the Apple review time has been abysmal, but hopefully it will be out in 5 to 10 days.

Posted in Updates

Version 1.5.3 is Available

This updates contains some corrections to motor data. I also changed the minimum required iOS version to 6.1.

Posted in Uncategorized, Updates

Rocket Calculator app feedback needed

If you’re a current or potential user of Rocket Calculator, please take a moment to fill out this brief survey, I’m working on a new, cross-platform version, and need your input. Thank you for your time.

Posted in Uncategorized, Updates

Version 1.5 is available

Version 1.5 update is available. Motors are managed better internally. The app now uses data compiled by Dave Walden, available on Rocketry Forum. The Quest motor data was compiled separately from the NAR website. The motor model number is now displayed on the Altitude Prediction screen.

I’ve started working on a cross-platform version that will run on iOS and Android devices. I’m still on track with having that available by end of summer. I’ll post updates on the status.

Posted in Updates

Version 1.4

This actually came out last week, but version 1.4 is available. It contains some minor motor updates and includes the newest versions of the NAR Model Rocket and High Power Rocket Safety codes (Available in the Info->quick reference section).

I intend to release a more comprehensive motor update within the next month, to include all the newer Cesaroni and Aerotech motors. I’m also planning the development of a cross-platform version that will run on iOS and Android devices. I’m hoping to have this by end-of-summer.

Posted in Updates

Version 1.3 is available

The update is available in the App Store.

For your reference, instructional videos for using the app are available here.

Posted in Updates

Version 1.3 Coming Soon






I submitted a Rocket Calculator update (version 1.3) yesterday, which should be available within the next few days to a week. The changes include the following:

  • Input option for elevation and temperature to compute correct air density. Used in altitude prediction as well as parachute and streamer descent rate calculators.
  • Changed altitude prediction calculator input field ‘Motor case mass’ to use ‘Total motor mass’ instead. This was more intuitive, allowing the user to enter initial motor weight and propellant weight.
  • Changed default descent rate for streamer calculator from 3 m/s to 4.5 m/s.
  • Added missing Cesaroni motors.
  • Changed app icon.
  • Changed app-launch image.
  • Minor bug fixes.

I just posted several videos demonstrating how to use most of the available calculators.

Posted in Updates

Update Available

Version 1.2 just got approved and is available for download.

What’s new:

– Corrections to motor data.
– Added the motor and body tube lookup buttons to the main Altitude Prediction screen.

Coming Soon ** Temperature and elevation inputs to calculate air density. This will replace the static air density value currently used for altitude prediction and descent rate calculators.

Posted in Updates

Update Available

The new update has some bug fixes and usability improvements. I also added the option to run Altitude Prediction calculations with zero drag.

I’m working on another update to the Altitude Prediction calculator that will use altitude and temperature to compute air density. Currently a static air density value is used. I’m also adding motor and body tube lookups to the main Altitude Prediction screen so they can be run without having to access the data assistant screen first.

Posted in Updates