This calculator provides ONLY a crude, unsafe estimate and must NEVER be used to decide if you can drive.
There is no validated formula that properly accounts for RYGB. This tool uses rough approximations from small studies and may be drastically wrong for your individual physiology.
Safe rule: If you have had more than 1-2 standard drinks, especially with any drunk feeling or memory gaps, do not drive until at least the next day after a full night's sleep, regardless of what this calculator says.