The Rule of 3s is a long-standing saying that isn’t really meant to be a “rule,” so much as a guideline. Because your body and circumstances are both different from anyone else’s, how long you’ll last without access to shelter, food, or water will vary greatly from other people that find themselves in tough situations. Your physical health, level of hydration, environment, and countless other variables will all affect how long you can go without basic provisions.

With that in mind, the Rule of 3s is still a great tool for establishing your survival plan and prioritizing your tasks, so let’s break the rule down:

You can survive:

  • 3 minutes without air or in icy water
  • 3 hours without shelter in harsh environments
  • 3 days without water
  • 3 weeks without food

Now, your environment may dictate that you prioritize shelter over water (in extreme cold or heat, for instance) but in environments where the weather is fine and temperatures stay moderate, you can place your focus on water first or in equal measure.

While these may not be hard and fast rules like the name suggests, they are guidelines that it pays to keep in mind whenever you’re in a survival situation.