Survival Rule of 3 – A Complete Survival Guide

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The survival rule of 3 are guidelines to help us remember our priorities in a survival situation. While many people treat this rule as scripture, it should be seen more as a guideline. Every individual and situation is different, so your priorities may differ. However, the survival rule of 3 is an easy way to remember what needs to be prioritized, helping you build a plan.

Survival Rule of 3
A man's hand holding a phone with no signal in a remote area

I reviewed these priorities with our military advisors and the survival handbooks I have. I researched these priorities and reference sources below that you can review yourself. I boiled all this research down and noted the most important points so that you can formulate your own survival plans.

These guidelines should be reviewed by anyone venturing outside for a hike, camp, or hunting trip and by anyone who wants to be prepared when an emergency occurs. These could range from your car breaking down in a remote area to a natural disaster or a larger widespread event.


Let’s dive in and see what our priorities should be in a survival situation.

What is the Survival Rule of 3?

The Survival Rule of 3 is:

  • You can survive for 3 minutes without air (oxygen) or in icy water.
  • You can survive for 3 hours without shelter in a harsh environment (unless in icy water)
  • You can survive for 3 days without water (if you have proper shelter in a harsh environment)
  • You can survive for 3 weeks without food (if you have water and shelter)

Keep in mind that these are general guidelines. A lot of other factors come into play here, such as the environment and the individual’s condition. The times for each of these can vary greatly, and some can blend.

Some environments are certainly more forgiving than others. You may not even need shelter in a tropical environment that is 75 degrees at night and 85 during the day. If you are in the mountains and it is snowing, or in the desert and it is 100 degrees, these environments present different challenges.

Individuals are also different. Someone used to hiking every weekend has different capabilities than someone that is out of shape and never hikes. Medical conditions such as asthma or diabetes are also considerations to keep in mind.

The main concept of the survival rule of 3 is to help set your priorities. If you can’t breathe, are injured, or are in icy water, this should be your priority before looking for food. Don’t take these as “rules” but rather guidelines that help you make the best decision for you and your situation.


Survival Rule of 3 Info Graphic

Air

The number one priority is having clean air to breathe. The survival rule of 3 gives us a guideline of 3 minutes without air, but this does not strictly mean holding your breath for three minutes. This applies to any condition restricting clean air and making you stop breathing and die. 

If you are inside a burning structure or vehicle, too much smoke can cause asphyxiation. Get out immediately. If you are in the water, keep your head above water and avoid drowning before drying your clothes. Studies on survival in icy water have found that the average person will only survive 1-1.5 hours after coming out of the water before succumbing to hypothermia.

The air can also be contaminated by smoke from wildfires, chemicals, or other man-made events. If the air outside is not breathable, a respirator is needed. In the case of man-made chemical spills or events, if you don’t have a respirator, it may only be safe inside if you have a secure location with an active air filtration system.

Some chemicals have no smell, so they can be challenging to identify. Look for signs of other people or animals in distress, seemingly for no reason. Pets are typically smaller than humans, so they are more prone to chemicals in the air. (This generalization is why miners used to take canaries into coal mines.)

If you notice an animal or person acting strange, fatigued, or dead, don’t enter an area without protection – or leave it if you’re already in it.

wildfire with smoke
Trying to escape a wildfire without a respirator can be deadly

In both cases having a respirator or mask for your family is a great investment. They take up some storage space, but having them will be invaluable during a wildfire or chemical event. Many try to escape wildfires by foot or in their vehicles only to succumb to smoke inhalation. See our guide on the best gas masks and respirators for more.

Choking on food is a more likely cause of the unexpected inability to breathe, as it is the fourth leading cause of accidental death. Many people, including myself, know someone who has died from choking on a common food. Learn the Heimlich maneuver, and don’t be afraid to use it.

Some less obvious conditions outside of having clean air that would fall into this category are injuries with severe bleeding. Treating severe injuries should be your next priority if clean air is available. Tourniquets should be in your IFAK and first aid kit. Know how to use them. Alternatively, a belt, rope, or any flexible type of material you can tie around an extremity will work as a tourniquet.

If someone stops breathing, perform CPR. If you are reading this and do not know how to do CPR, sign up for a local class here. Everyone should know basic first aid and CPR.

Always keep at least an IFAK with you at all times or a complete first aid kit if you have space. First aid supplies are critical and the first step in being prepared.

See our Best IFAK Guide and How to Choose the Best First Aid Kit for expert tips on what you need in yours. Also check out our picks for the Best First Aid Kits for Survival.

Also, see our MyMedic Review for some first aid kit options, along with a special discount for survival stoic readers. For the best kit we have found to travel with, check out our Redi Roadie Emergency Kit review.

Shelter

You start planning for protection from the weather after you and everyone in your group have clean air to breathe and no injuries (or are in stable condition). The survival rule of 3 gives us a guideline of 3 hours without shelter. This, of course, can depend on our environment and may be better thought of as “warmth” instead of shelter.

Your body loses and gains heat in multiple ways. 

  • Convection occurs naturally through the movement of air or water. Warmth is transferred from a warmer item to a cooler one. This occurs when you are in cool or warm air. Sweat, being wet, and the wind amplifies the cooling effect.
  • Conduction occurs when touching other items that are hot or cold. This could be the ground, floor, or another person. You also lose body heat when you breathe, eat, and drink cold things. Eating snow for water is a good example. Since the snow is essentially ice, you are internally reducing your body temperature through conduction.
  • Radiant heat is heat from the sun or sitting in front of a fire. 

From these three basic methods, we can understand what is helpful for us to stay warm. Wind, being wet, cold air, laying on something cold, and drinking something cold all pull heat from our bodies. Fire, the sun, insulation between us and other cold items, warmth from other people, and drinking something warm are adding heat to our bodies.

5 men in the cold looking for shelter - one is injured
Shelter is our second priority after air and treating injuries

Building a survival shelter is a core bushcraft skill and solves most of these issues. A fire near your shelter will provide heat to warm both your body and the area around you. 

Shelters can take many forms, from a survival tent, building, vehicle, or tarp. When thinking about shelter, wind and water are the main things to keep in mind. You want protection from both. Make sure to also have an insulating layer between you and the ground.

Fire is also essential as a priority with shelter. Not to mention its warmth, it is also a great morale booster. Even if you are not in a cold environment, fire can also purify water and signal for help.

If you are in a temperate environment, a shelter may not be as high of a priority. It could come close to water in priority. However, the nights can be cool even if the weather is warm during the day. If it rains and you are soaking wet, you can still develop hypothermia in temperatures as warm as 60 degrees.

In a very hot environment, shelter from the sun’s heat during the day is important. Except for the desert, most areas have some form of natural shade. In very hot environments, water could be just as important as shelter. Heat Stroke is also a concern, so staying cool and hydrated and minimizing exertion and exposure to the sun during the hottest part of the day are important.

Keeping essential survival tools and gear like a fire-starting kit, survival blanket, a survival tarp, and extra clothes with you is the minimum to satisfy shelter requirements. More may be needed depending on the environment that you are traveling in. In very cold weather, wool blankets are a good option, along with an survival hatchet, survival saw, or a survival multitool for cutting firewood.

Water

After air and shelter, water should be your next priority. While the survival rule of 3 gives a guideline of 3 days without water, this can be much less under certain conditions. One example is in very hot conditions where you are exerting yourself. However, don’t assume you can go longer than 3 days in cold conditions. The body uses a lot of water in very cold conditions to keep you warm.

You should drink 64 ounces of water per day (1/2 gallon). This depends on the environment, your diet, your general health level, and how active you are.

Since water weighs over 8 pounds per gallon, it is not practical to carry two days of water with you on a hiking trip, just in case. As an alternative, keep in mind where you can source water. 

Always question if the water is clean, even if it looks clean. Water in more populated urban areas is more likely to be contaminated, but water in rural areas can also make you sick. If you are already in a survival situation, becoming sick from bad water will just add to your problems. But, if you have no choice and have gone a day or two without water, taking the chance may be worth it instead of dying of dehydration.

A man's hand holding a cup and dipping it into a clear shallow stream
Don’t assume clean looking water is safe to drink

Look for signs of contamination, such as the smell, appearance, or dead insects and animals around the water. In general, moving water is better than stagnant water. If the water does not seem to be contaminated, it should still be treated before drinking.

This is where our previous priorities of warmth and fire come into play. Boiling water will kill bacteria and parasites that could make you sick. See our guide on how to boil without electricity for many methods you can use.

Without fire and some sort of container, this is difficult. As an alternative, water filters and purification tablets can also be used. See our review on the best survival water filters for some great options.

As mentioned earlier, eating snow will reduce your body temperature. If you have fire and a container, finding water is super easy when there is snow. Just be careful of that yellow snow! Snow can also be melted in a sock or fabric, but you still need fire to warm and melt it.

So, water needs to stay high on our priority list. After you have warmth covered, quickly pivot to solving how to get clean water. At a minimum, keep a metal container, water filter, and water purification tablets with you to satisfy your water requirements. More may be needed in extreme cases.

Food

After air, shelter, and water, food should be your next priority. While the survival rule of 3 gives a guideline of 3 weeks without water, again, this can be much less under certain conditions.

Similarly to the other items we discussed, the amount of food you need depends on the individual. You can survive for months if you have water and a small amount of food. A British Medical Journal Study found that once individuals lost 10% of their body weight, symptoms such as fainting and dizziness occurred, with some becoming almost bedbound. In a survival situation, this is certainly not helpful.

Some people think of food first before the other priorities above. It is probably because they not only get hungry, but they also get “hangry”; very angry when they are hungry. While a snickers bar may solve this easily, it should be the lowest priority. Hunger is mostly a mental issue. Naturally, for some, it is harder than for others.

Most survival situations end before food is needed, either because one of the other priorities was not met or the situation ended in rescue. Food solves many mental issues associated with hunger if all other priorities are covered.

A man in the Wilderness sneaking with a large knife.
Don’t be Rambo hunting a rabbit if you don’t have the other priorities covered

If you are hiking, hunting, camping, or traveling away from civilization, keep more survival food with you than you think you will need. Pack items that are calorie dense and nutritious at the same time. They should have a good balance of fat, carbs, and protein. Ration bars are a good choice since they do not require cooking and are lightweight.

Food is not only the lowest priority as far as focus is concerned but also in practice. Do not eat unless you have plenty of water. The body needs water for digestion, and eating without water will speed up dehydration.

Remember that food is the lowest priority. If you are in a survival situation, there is likely to be someone that will be hyper-focused on the next meal. Keep food in your survival kit, but don’t let it consume your thoughts or derail the other priorities.

Mindset

Like most things in life, if our mind is not in the right place, we do not stand much chance of success. Keeping tabs on our thoughts is more important than any of the priorities above. While the rule of 3 doesn’t mention mindset, most people wouldn’t survive three days (or even three seconds, in some cases) without the right mindset.

Once you realize you are in a survival situation, it is likely you made a mistake. You did not prepare, were complacent, and now realize that you don’t know how to get out of it. Or maybe it is not a mistake you made. Maybe someone else made the mistake or intentionally put you and your family in harm’s way. 

No plan survives first contact – no matter how well you prepare.

The stoic men taught that no matter the reason for our current situation, we have a choice in how we respond. Do we get upset, wondering what others will think, complain, get mad, or just break down emotionally? Or do we stop, remember this article, and think about the correct priorities? The choice is 100% ours to make and no one else.

beautiful sunset over a remote lake
It is our choice how we respond to a situation

When George Washington’s soldiers were freezing in Valley Forge, he wrote, “It is in vain to ruminate upon, or even reflect upon the authors or causes of our present misfortunes. Instead of looking backward, we should rather exert ourselves.”

Forget about what happened. Focus on the proper steps to get you to a better situation.

Seneca faced many difficult moments, from being exiled to working for a tyrannical emperor who ultimately ordered his death. In a famous stoic quote, he wrote, “How does it help…to make troubles heavier by bemoaning them.” Our thoughts often make situations worse than they are.

Marcus Aurelius was a Roman emperor who faced plagues, wars, and more stress than anyone could imagine. He wrote in his journal, “It’s unfortunate that this has happened. No. It’s fortunate that this has happened, and I’ve remained unharmed.” 

Being mentally “harmed” is your choice. Be mindful of your thoughts. Stop and think when a situation seems unbearable and thoughts are racing through your mind. Take a short walk to clear your mind. Set small goals. Is everyone ok? Yes, then let’s find some shelter from the rain. Hey, I can use this poncho to collect some rainwater.

You would be surprised at what you can accomplish when you decide to do something. It is your choice.


Prepare a Survival Kit

Of course, the best solution to getting out of a survival situation is to never get into it in the first place. If we prepare our minds and plan for the situation ahead of time, our chance of success goes way up. Seneca wrote, “Luck is what happens when preparation meets opportunity.” Before traveling, whether it be a drive, a hike, hunting, or a camping trip, make sure you have prepared.

For a detailed strategy on building your own survival kit, see our Survival Gear List Strategy Guide.

  1. Have a plan and ensure someone not with you knows the plan. If you are not back as planned, they can call for help.
  2. Pack a first aid kit. See our guide on how to choose the best first aid kit.
  3. Have a way to communicate. This could be a radio, Satellite communicator, or whistle.
  4. Use a handheld GPS or GPS survival watch. Your phone may lose signal, or the battery may run down. With modern technology, getting lost should never happen. At a minimum, pack a survival compass and map of the area.
  5. Pack a fire-starting kit, an emergency sleeping bag, a waterproof tarp, a bushcraft knife, a Swiss Army knife or Survival Multitool, and extra clothes in a durable backpack.
  6. Pack a metal container, survival water filter, and water purification tablets.
  7. Pack a calorie-dense food, more than you think you will need.
  8. Pack a signaling device like a signal mirror, whistle, and a bright bandana.
  9. If you are driving, keep a tow strap, blanket, extra water, and a portable jump start unit in your car.
  10. At home, keep your bug out bag essentials packed in case a evacuation situation occurs, and you must leave quickly.

What are the First Three Priorities if you Become Lost?

If you are out in the wilderness and become lost, your first three priorities should be shelter, fire, and prepare to signal for help. After these have been taken care of, a source of clean water should be next.

If you followed our preparation tips above, it is likely help will arrive within 48 hours. Stay calm and don’t forget the mental aspect of survival.


Now You Will Survive

The survival rule of 3 gives us general guidelines for our priorities in a survival situation. These are not hard rules and can vary depending on the individual and situation.

A good way to see this rule in action is to watch a season of Alone. Even if the contestants select the perfect 10 items from the Alone gear list, and shelter, water, and food are satisfied, mindset also comes into play.

Stay prepared, but if you are faced with a survival situation, be mindful of your thoughts and remember that air, shelter, water, and food are your priorities.

To stay prepared for emergencies, be sure to check out our full Prepping Guide. Many of the same concepts apply when reacting to emergencies.

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Jason has an engineering and problem solving background. He is an avid outdoorsman, survivalist, and competitive shooter. He enjoys researching the best and most practical solutions for the problem at hand, studying stoicism, and finding innovative ways to be prepared.