On a clear day, you can navigate by eye: that ridge, that church spire, that line of trees. Then the cloud comes down and the landscape vanishes. A compass is the tool that keeps you moving in the right direction when you cannot see more than a few metres. It is cheap, light and does not need batteries, and learning the basics takes only a short afternoon.

The parts of a compass

A typical walker's compass has a clear base plate with a ruler edge, a rotating housing marked in degrees, a needle that swings freely and a direction of travel arrow. The red end of the needle points to magnetic north. Inside the housing there is an orienting arrow and a set of parallel orienting lines.

Taking a bearing from the map

A bearing is simply a direction expressed in degrees from north. Here is how to take one from an Ordnance Survey map:

Lay the compass on the map so that the long edge connects your current position with your destination. The direction of travel arrow should point towards the destination.
Turn the housing until the orienting lines are parallel with the north-south grid lines on the map, and the north mark on the housing points to the top of the map.
Read the bearing at the index line, where the housing meets the base plate.
Allow for magnetic variation. Grid north on the map and magnetic north are not exactly the same, and the difference changes slowly over time. The map margin gives the current figure for the area, so adjust your bearing accordingly. In Britain the difference is small compared with some parts of the world, but it can add up over a long distance.

If you are new to maps, our guide on how to read an OS map is a good place to start.

Following the bearing

Once the bearing is set, take the compass off the map, hold it flat in front of you and turn your whole body until the red end of the needle sits inside the orienting arrow. Many walkers remember this as putting red in the shed. The direction of travel arrow now points the way to go.

Do not stare at the compass while walking. Pick a feature in the distance along the line, such as a rock or a post, walk to it and then check again. In thick mist, a companion can walk ahead as a marker and you can guide them left or right to keep them on line.

Combine the compass with other clues

A compass works best when combined with the map and the ground around you.

Handrails are linear features such as a wall, a stream or a fence that you can follow.
Timing helps you estimate how far you have come. If you are not familiar with timing rules, see our explanation of how long a walk will take.
Pacing means counting steps over a known distance, which gives a rough measure of how far you have walked.
Catching features are things you expect to find, such as a path junction or a change of slope, that tell you that you are on track.

If what you see does not match the map, stop. Do not force a bearing. Retrace your steps to a place you know and start again.

Practise before you need it

Pick a clear day and a safe, open area such as a park or a small hill. Set a bearing, walk along it for a few hundred metres, then try to return the same way. Practise on easy ground so the techniques are familiar when conditions are poor.

Know your limits

Compass skills reduce risk, but they do not make it vanish. If visibility is very poor, the weather is severe or you feel unsure, the safest decision is often to turn back. Courses run by outdoor centres and walking clubs are an excellent way to build confidence with an experienced instructor.

Frequently asked questions

Can I rely on my phone instead of a compass? Phones are useful, but batteries fail and signal can disappear in the hills. A compass is a lightweight backup that always works.

Do magnets or metal affect a compass? Yes. Keep it away from phones, car bodies, knives and other metal objects when taking a reading.

What is the difference between grid north and magnetic north? Grid north follows the lines on the map, while magnetic north is where a compass needle points. The angle between them is the magnetic variation.

Steps

Take a bearing from the map: Lay the edge of the compass along the line from where you are to where you want to go, with the direction of travel arrow pointing towards your destination.
Set the housing: Turn the compass housing until its orienting lines sit parallel to the north-south grid lines, with the north mark pointing to the top of the map.
Allow for magnetic variation: Adjust the bearing as shown in the map margin so that it matches the magnetic needle.
Follow the bearing: Hold the compass level, turn your body until the needle sits inside the orienting arrow, and walk in the direction the travel arrow points.

Compass Basics: Finding Your Way When Visibility Drops