How to Use a Compass
Find north, take and follow a bearing, take a bearing from a map, correct it for magnetic declination, and detour around an obstacle with a baseplate compass.
You will end up able to find north, take a bearing on a landmark, follow a bearing across open ground, take a bearing from a map, and correct it for magnetic declination, all with a baseplate compass. A compass has no batteries and needs no signal. The part that does the work is a magnetized needle that lines up with the Earth's magnetic field, and it works in rain, snow, and darkness.
Magnetic compasses have been guiding travelers for more than 800 years. Sometime in the 12th century, mariners in China and Europe discovered, apparently independently, that a piece of lodestone floated on a stick in water turns to point toward the polestar. Everything else on a modern compass exists to help you read that needle.
Carry the compass with a paper map, and tell someone where you are going and when to expect you back, which is the National Park Service's advice before any trip. The steps take the skills in order, and the closing gives a drill for practicing them close to home.
A baseplate compass, the kind with a rotating bezel and a direction-of-travel arrow. Suunto and Silva both make them. Choose one with adjustable declination if you can, because you set it once for an area instead of correcting every map bearing by hand (step 7). Leave out button compasses, ball compasses, and novelty compasses, which have no bezel or baseplate to take a bearing with. For the map steps, add a topographic map of a nearby area. The U.S. Geological Survey's topographic maps are free to download, so you can print the area you want to practice in.
Learn the parts of your compass
A baseplate compass has eight parts to know. The baseplate is the flat, transparent plastic rectangle you hold. It is see-through so you can place it on a map and read features underneath. The magnetic needle sits in the center housing, floating in liquid so it can rotate freely. The red end points toward magnetic north. The rotating bezel (also called the azimuth ring) is the dial around the needle housing, marked from 0 to 360 degrees. You turn it to set bearings. The direction-of-travel arrow is printed on the baseplate, pointing away from you when you hold the compass. This arrow tells you which way to walk. Inside the bezel housing, you will find the orienting arrow, a large outlined arrow etched into the base of the rotating capsule. When you turn the bezel, this arrow moves with it. The orienting lines are the parallel lines inside the housing that run the same direction as the orienting arrow. You use them to align the compass with a map's meridians (step 6). The index line is the small mark on the baseplate where you read your bearing number. The eighth is the set of ruler markings and map scales along the edges of the baseplate, for measuring distances on a map.
Hold the compass correctly
Hold the compass flat in both hands in front of you, between waist and chest height, with your elbows tucked against your sides and the direction-of-travel arrow pointing straight ahead, away from your body. Suunto's own instructions say to hold it level at waist height. Level is the part that matters. If you tilt the compass, the needle drags against the housing and gives a wrong reading. Held this way, the direction-of-travel arrow points the same way your body faces.
Good to know: Keep the compass away from magnets, electronics, and iron or steel. Silva's manual for its baseplate compasses names knives, mobile phones, radio speakers, and magnets, and warns that storing a compass close to them can reverse the needle so that it points south instead of north. Take every reading with your phone in a different pocket and the compass clear of your belt buckle, knife, and car keys. Aluminum is not magnetic, so an aluminum trekking pole or carabiner does not deflect the needle, and a steel one does. FAQ 4 below shows how to check for a reversed needle.
Find north and orient yourself
Hold the compass flat and let the needle settle, which takes a few seconds. The red end of the needle points to magnetic north. Now rotate the bezel until the orienting arrow (the outlined arrow inside the housing) lines up directly underneath the red end of the needle. This is called putting red in the shed. The N on the bezel now points north. Look up from the compass and pick out what lies to the north, such as a distant peak, a tree line, or a building. With north fixed, you have the other directions too. If your destination is roughly southwest, you know the general direction to walk before you take a precise bearing. Repeat this check whenever you stop, because every later step starts from red in the shed.
Take a bearing on a landmark
A bearing is a direction measured in degrees clockwise from north. Due north is 0 (or 360), due east is 90, due south is 180, and due west is 270. To take a bearing on something you can see, such as a hilltop, a fire tower, or a trail junction across a valley, point the direction-of-travel arrow directly at it. Keep the compass flat and steady. Without moving the compass, rotate the bezel until the orienting arrow frames the red end of the magnetic needle, which is red in the shed again. Now read the number at the index line. That number is your bearing to the landmark, so write it down. If fog or darkness hides the landmark before you set off, you can still follow the bearing to it from where you stand (step 5). To come back the way you went, use the back bearing, which is the opposite direction. Add 180 to a bearing below 180, and subtract 180 from a bearing of 180 or more. The back bearing of 70 is 250, and the back bearing of 250 is 70.
Good to know: Aim with your whole body, not your wrists. Turn your feet until you face the landmark squarely, with your elbows still against your sides as in step 2. The direction-of-travel arrow then points at the landmark, and the compass stays level while you turn the bezel.
Follow a bearing
You have a bearing, either the one you took in step 4 or one from a map (steps 6 and 7). Turn the bezel until that number sits at the index line, and then leave the bezel alone, because turning it changes the bearing. Hold the compass flat and rotate your entire body, not the compass alone, until the red end of the needle sits inside the orienting arrow. The direction-of-travel arrow now points along your bearing. Pick a landmark in that direction that you can walk to without looking at the compass, such as a specific tree, a boulder, or a rock outcrop. Put the compass away and walk to it. When you reach it, take the compass out again, rotate your body until red is in the shed, and pick the next landmark. Repeat until you reach your destination. Walking from landmark to landmark holds the line, where walking with your eyes on the needle does not, because the needle swings with every step.
Heads up: Before each new leg, look at the index line and confirm it still shows your bearing. If the bezel has been bumped, turn it back to the number you wrote down before you line up the needle.
Take a bearing from a map
Lay the map flat and ignore the magnetic needle for this step. You are measuring an angle on the map, and the needle plays no part in it. Place the long edge of the compass baseplate on the map so it connects your current position to your destination, with the direction-of-travel arrow pointing toward the destination. If the arrow points back toward your starting point, the bearing comes out exactly 180 degrees wrong. Rotate the bezel until the orienting lines inside the housing run parallel to the map's meridians, the north-south lines that point to true north, with the N on the bezel toward the top of the map. Line up the orienting lines, not the orienting arrow. Silva's manual says to use the lines and not the arrow as the map's north reference once the declination adjustment has been set. Read the bearing at the index line. This is your map bearing, and step 7 corrects it for declination before you walk it. On a USGS US Topo map, the 1,000-meter grid printed across the map is a UTM grid. USGS says it points to grid north, which differs from true north, and the diagram at the bottom of the map shows the angle between them. To measure from true north, line the orienting lines up with the left or right edge of the map, which runs along a line of longitude. To measure the distance to your destination, hold the ruler or map scale on the edge of the baseplate against the route and read it with the map's scale.
Adjust for magnetic declination
True north (where the map's meridians point) and magnetic north (where your compass needle points) are not the same direction. The angle between them is called magnetic declination, and it varies by location. NOAA's calculator, queried for October 2026, gives about 14 degrees west for Boston and under 6 degrees west for Atlanta, and about 15 degrees east for Seattle and 7.5 degrees east for Denver. The error grows with distance. Each degree puts you about 17 meters off for every kilometer you walk, so ignoring 14 degrees over 3 kilometers leaves you about 730 meters from where you meant to be. Look up your local declination with NOAA's magnetic field calculator before your trip, and again for each new area. If your compass has adjustable declination, set it once for the area you are in, following the instructions that came with it. On Silva's adjustable models, for example, you turn a screw on the bezel with the small screwdriver stored in the lanyard's safety release until the orienting arrow meets your value on the declination scale. A map bearing from step 6 then needs no arithmetic. If your compass has no adjustment, correct each map bearing by hand before you walk it. For west declination, add the degrees to the map bearing. For east declination, subtract them. A map bearing of 60 becomes 74 in Boston (60 plus 14) and 45 in Seattle (60 minus 15). The mnemonic is west is best (add), east is least (subtract). The same compass needs the reverse correction when you draw a bearing you took in the field onto the map. Subtract west declination and add east. If a result goes above 360, subtract 360, and if it goes below 0, add 360.
Heads up: Declination drifts as the Earth's magnetic field changes. NOAA's model has Seattle's value changing by about 0.12 degrees a year and Boston's by about 0.07, which adds up to a degree in roughly 8 years at Seattle and 14 at Boston. USGS notes that the declination printed on an old map might no longer be accurate, so look up the current value before each trip.
Navigate around obstacles
When you are following a bearing and reach something you cannot walk through, such as a lake, a cliff, or dense brush, go around it with a 90-degree offset instead of judging a path by eye. Take every turn from the compass. To turn right, add 90 to your bearing, and to turn left, subtract 90. If the result passes 360, subtract 360, and if it drops below 0, add 360. On a bearing of 40, the right turn is 130 and the left turn is 310. First, turn 90 degrees to the right (or left) and count your steps as you walk, until you are clear of the side of the obstacle. Second, turn back onto your original bearing and walk until you are past the obstacle. Third, turn 90 degrees toward your original line and walk the same number of steps you counted on the first leg. You are now back on your original line, so turn onto your original bearing and carry on. The detour traces three sides of a rectangle, and the leg back has to be the same length as the leg out, which is why the count has to be exact. The steps on the middle leg count toward your distance along the bearing, so add them to your running total. Count in double-steps, one for each time your left foot hits the ground. To turn the count into distance, walk a measured 100 meters beforehand and note your own number.
Practice in a park you know before you rely on any of this. Walk a triangle. Set a bearing and walk 200 steps, add 120 to the bearing and walk 200 more, then add 120 again and walk the last 200, subtracting 360 whenever the number passes 360. You should finish close to where you started. If you finish well off, check two things. At each corner, you should have turned the bezel to the new number once and then turned your whole body to bring red into the shed (step 5), and your step count should have been the same on all three sides. If a bearing from the map sends you the opposite way, the direction-of-travel arrow was pointing toward your start when you laid the compass on the map (step 6). If a map bearing lands you to one side of the target, redo the declination arithmetic in step 7 and check whether you added where you should have subtracted. If the needle is slow to settle or disagrees with a second compass, read FAQ 4 below before you trust it. Then move on to short routes between landmarks with the map, on ground where a mistake costs you nothing.
Questions we get asked about this
Answers from experience, not a textbook.
A baseplate compass with a rotating bezel and a direction-of-travel arrow. Suunto describes its A-10 as a compass for general recreational use, and Silva lists the Starter 1-2-3 at its basic user level. Neither has adjustable declination. Both makers list a fixed declination scale instead, so you correct for declination by hand, as step 7 explains. To set it once for an area, look for adjustable declination in the specifications. Suunto's MC-2 mirror compass has it. If you will travel outside your home hemisphere, read FAQ 2 below before you buy.
The needle responds to the Earth's magnetic field anywhere, but each compass is balanced for one part of the world. The field lines tilt into the ground more steeply the closer you get to a magnetic pole, and makers weight the needle so it stays level in one zone. Suunto sells its compasses with needles balanced for the northern hemisphere or the southern hemisphere, and Silva balances its compasses for one of three zones. Silva's manual says that in the wrong zone the needle tilts, and that it can stick against the capsule and show an incorrect north. For travel between zones, buy a compass with a global needle, which both makers sell. At the magnetic poles themselves the field lines are vertical, so the needle has no horizontal direction to settle on.
Not on its own. A phone compass works, but it depends on the battery and on calibration. Google's instruction for a phone whose direction beam is wide or points the wrong way is to move the phone in a figure 8 until the beam narrows, and our guide on how to fix GPS not working covers that calibration. The National Park Service's Ten Essentials list puts a map, a compass, and a GPS together under navigation. It says to bring a physical map as a backup and to pack an extra battery for your phone. On any trip where getting lost has consequences, carry the baseplate compass and the paper map as well as the phone, and keep the phone in a different pocket from the compass (step 2).
Hold it flat and let the needle settle. It should settle within a few seconds and point the same way every time, without sticking or wobbling endlessly. Then check that it points the right way, because the dangerous fault looks perfectly healthy. A strong magnet close to the compass, such as a phone, a magnetic phone case, or a speaker, can reverse the needle so the red end points south. The Mountaineering Council of Scotland's safety advisor describes a sluggish needle that seems to stick as a sign of partial reversal, and reports a fully reversed needle sitting roughly 10 degrees off exact, so reading the south end instead is not reliable. To check, hold it beside a second compass. Both needles should agree within a degree or two. A phone compass is accurate enough to catch a needle pointing the wrong way. Do this before you leave home, and do not navigate with a compass that fails it.
No. A compass alone gives you direction. You can find north (step 3), follow a bearing (step 5), and return on the back bearing (step 4). That is enough for walking a straight line to a road, a river, or a shoreline you know lies to the west. A map adds position. With one you can plan a route, read the terrain ahead, and measure distance. You can also fix where you are. Take bearings on two landmarks that you can find on the map, convert each with the field-to-map rule in step 7, and draw each line on the map through its landmark. You are where the two lines cross.
A bearing is the direction from one point to another, measured in degrees from north. A heading is the direction you are currently facing. They are the same when you face directly toward your destination. If you detour around an obstacle, your heading changes temporarily but your intended bearing stays the same. When you clear the obstacle and turn back, you resume walking on the original bearing. Think of a bearing as the direction you want to go and a heading as the direction you are actually pointed right now.