The ten essentials: a list of systems you scale to the trip

The ten essentials are a set of systems for dealing with the problems a day outdoors can create: losing the route, losing the light, getting too hot or cold, getting hurt, needing to make a fire, being stuck overnight, running short of food or water. Each system is a group of items that solves one of those problems. The version followed here is the National Park Service list of ten categories. The sections below group related items together, and each one gives the reason for it.

Navigation and light

The first system is navigation: a map, a compass and, if you use one, a GPS unit. The National Park Service advises knowing how to use a topographic map, compass or GPS unit before you go, and carrying a physical map as a backup even if you use a phone. A phone is an extra, not the whole system. Its battery and screen can fail, so pack a spare battery for it.

The map and compass are only useful if you can read them. The map scale guide explains how distance on a map becomes distance on the ground. The true north and magnetic declination guide explains why a compass needle and a map can disagree. Both are worth reading before a trip, when the stakes are low.

The illumination system is a light, and the National Park Service recommends a headlamp, because it leaves both hands free for the route. Pack extra batteries. Light matters most when the day runs longer than planned. The sunset and remaining daylight guide and the turnaround time guide show how to decide, before the trip, when you need the headlamp and when you should be heading back.

Sun protection and extra clothing

Sun protection means sunglasses, sunscreen and a hat. The National Park Service notes that harsh UV rays are responsible for sunburn and skin cancer, and that long sleeves and long trousers also reduce exposure. Sun and heat often come together, and the heat index guide covers how heat is measured for hikers.

The extra clothing system is a layer that suits the most extreme conditions you could meet. The National Park Service suggests a raincoat, a jacket, a hat and gloves, and says to prepare for sudden changes in the weather. The layer is there to keep you warm when you have stopped moving, and when the wind picks up.

The wind chill guide explains how wind changes the temperature a person feels, and the temperature drop with altitude guide covers how temperature changes as a route climbs. The Feels like tool applies the wind chill and heat index formulas to a temperature, wind and humidity you enter.

First aid, fire and repair

The first aid system is a kit. The National Park Service suggests starting from a pre-made kit and changing it to fit the trip and your own medical needs. Include any personal medicines you take regularly. A kit is only useful to someone who knows how to use it, so take a course in first aid, and practise with the items in the kit before the trip. Cold injuries are one example of a problem that a kit alone does not solve.

Read the cold stress note and take training before you rely on the kit for a cold injury. The list here does not give medical instructions.

The fire system is matches or a lighter, plus a fire starter that catches quickly and keeps a flame going. The National Park Service notes that fire can be an emergency signal and a heat source for cooking and staying warm. Check the local fire regulations before you go, because the rules change by place and season. Keep flames and stoves outside any shelter, including a tarp.

The repair system is a basic kit of duct tape, a knife, scissors and a multi-tool. The National Park Service lists a knife, duct tape and scissors in the basic repair kit, and suggests a multi-tool for the rest. It also advises bringing any tools specific to the trip and the activity.

Food, water and emergency shelter

The nutrition system is an extra day of food. The National Park Service recommends food that needs no cooking and gives energy, such as trail mix, nuts and granola bars, and it suggests salty, easily digested snacks. The extra day is there for an unplanned night or a late return. The backpacking food weight guide shows how much food a trip needs by weight, and the Food carry tool turns a calorie target and an energy density into grams per person per day. The calorie target is yours to set.

The hydration system is water and the means to treat it. The National Park Service advises identifying water sources at the destination before you go, and carrying the supplies to treat water from them. Two guides cover the decisions. The how long to boil water guide covers boiling, and the water filter and purifier guide compares two other methods. The Water decisions tool is an educational aid for choosing a method, and it does not test water quality.

The emergency shelter system is a tent, a tarp, a bivy sack or an emergency space blanket. The National Park Service lists each as a lightweight option for an unplanned night outside. A tarp needs to be pitched correctly to be useful, and the A-frame tarp geometry guide shows how ridge height and width set the shape of the shelter.

Scale the list to the trip

The ten essentials are a set of systems, not a checklist with a fixed quantity. A two-hour walk on a marked trail, a half-day route in a national park and a three-day trip into remote ground each need the same categories, but different amounts. The distance from help, the season and the number of people in the party all change the size of each system. The National Park Service adds that some activities need additional items, such as a life jacket or a two-way satellite messaging device, on top of the ten.

A practical method is to start with the trip’s longest plausible delay. For a route where the return could take an extra night, the food, shelter and water systems need to cover that night. For a short walk within sight of a road, they can be much smaller. Write the amounts beside each system, then weigh the result. The Pack ledger tool sorts items into categories, including essentials, and gives a base weight, which shows how much the systems add before food and water are counted.

Where the list stops

The list names what to carry, but it does not teach the skills needed to use it. A map is of little use to someone who cannot read contours, and a first aid kit is of little use to someone who has not practised with it. Training from a recognised course, and practice on the ground near home, matter more than the number of items in the pack. The list is also not a rule about weight. Each item should earn its place by solving a problem on the route you actually plan to walk.