While not commonly heard of, the Rule of Three is a standard of measurement to determine how long a person can live under certain circumstances. This rule is used mainly in forensics and for military purposes. Basically, the purpose of the rule is to set a general guideline as to how long a person can survive without Air, Water, & Food and derived its name from the abundance of threes in the results.

Averages:
- Air = 3 Minutes
- Water = 3 Days
- Food = 3 Weeks


The rule regarding water is based on a person that is fully hydrated at the beginning of deprivation. If you are already dehydrated the time to live will be increasingly shorter. It is also important to note that in cooler temperatures the time to live will be closer to 4 days due to a reduction in body perspiration.

I hope never to find myself in a situation where I need to know this, and hope the same goes for you. I do know that in certain military situations this information is used to allow a soldier to prioritize his/her objectives when stranded or in a situation without food and water.