This is an arterial blood gas interpreter for use by internal medicine, renal, pulmonary and critical care students, residents, fellows, nurses and therapists. It is a learning tool that can be used to better understand the meaning of a blood gas sample. This software is not clinically validated and is not approved as a tool by any governing body. Clinical interpretation of a blood gas should be done by a qualified physician or equivalent entity. It calculates Aa-gradients and PO2/FiO2 ratios as well as doing acid base interprretation. This application as a learning tool is always open for improvement. Any suggestions are appreciated.