Handwashing timer

Twenty seconds of scrubbing, not counting wetting and rinsing. It is the figure the CDC and the WHO converged on, and the reason for the two-rounds-of-Happy-Birthday advice.

Most of the work happens between the fingers, around the thumbs and under the nails, which are the places a quick rinse always misses. Soap and friction do the job; water temperature makes almost no measurable difference.

Twenty seconds is much longer than it feels, which is the entire reason to time it once and calibrate.

Or set any length you like: gotimer.app