bytran is an application for calculating atmospheric and molecular absorption spectra using the HITRAN database and the line-by-line method. The concentrations of molecules, pathlength, atmospheric pressure, temperature, and other input parameters are used to model the gas mixture optical transmission spectra as a function of wavelength.

Additional information is available at the bytran website and in the following publication, (a view only version of this publication is available at

What’s New

Version 1.3.2

1) Fixed a mistake in the bytran algorithm in that the Loschmidt's number was specified at a standard temperature of 273.15K instead of at 296K (an ~ 8% difference).

2) Fixed a programming error preventing the usage of the external storage causing bytran to terminate after the HITRAN database downloads and on program quit.

For a complete list of changes and bug fixes please refer to:

App Privacy

The developer, Dzianis Pliutau, has not provided details about its privacy practices and handling of data to Apple. For more information, see the developer’s privacy policy.

No Details Provided

The developer will be required to provide privacy details when they submit their next app update.


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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