Recently I have begun a personal challenge of being able to hold my breath for 3 minutes. As part of my training, I have consulted free diving resources (who should be experts on this), and have learned about CO2 Tables, which are designed to increase an individual’s ability to deal with CO2 in an efficient way when under low oxygen environments.
The following is a Google drive spreadsheet I made which will calculate a CO2 table based on my max breath hold: CO2 Calculator. I wasn’t able to find a site online that did this for you quickly, so I figured I’d share mine as an example. I am not a medical professional, and this is not advice! Holding your breath for extended periods of time can be dangerous, so if you also decide to try something similar please take all necessary precautions in order to stay as safe as possible.
Andy Gallup 