Standard Atmosphere Calculator

This calculator is based on the 1976 model of the U.S. Standard Atmosphere (NASA-TM-X-74335).

Two input options are modeled, you can either provide:

  • altitude and ambient temperature
  • altitude and temperature offset (from Std. Atm.)

US Std. Atm. + Air Temperature



Density Altitude:


Air Density:

Relative Density:

(SL ISA=1)

Sonic Speed:


Disclaimer (the simple version):

I have made every effort to ensure that all the calculations that form part of this tool are correct and accurate, I have back-tested it and validated it against the NASA-TM-X-74335 report. HOWEVER, I cannot and do not guarantee that the results output from the calculator are correct. You should always double check the results being output – especially if you are using the results for engineering calculations. Finally, if you do discover any bugs in the calculations I would really appreciate it if you would drop me an email at and let me know so I can make the correction.

Disclaimer (the legal version): has made this atmospheric calculator freely available to use by accessing it from the address. Be aware that the content on this site is copyrighted and redistribution or copying of this content is prohibited. The release of this calculator does not and cannot warrant that any functions contained within are accurate or error free. The use of this software comes with NO WARRANTY or LIABILITY of any kind. The entire risk as to the software applicability, performance and quality lies solely with you as the user and not It is the responsibility of the user to ensure that the correct values have been selected at all times and to cross-reference the results with those contained in NASA-TM-X-74335. In no circumstance or event shall, or the domain owner associated with the website, be liable for any damages, whether direct or indirect, incidental, special, or consequential arising out the use of or any defect inherent in the software. By using this calculator, you as the user expressly agree to the terms of this disclaimer in full.