CompassPro FAQ
Answers about CompassPro, from reading the compass to finding the Qibla.
Last Updated: November 13, 2026
1. General Questions
Q1: What is CompassPro?
A1: A compass that runs in your browser. On a phone or tablet the dial follows the built-in compass; on a computer you turn it by hand. Around it are the tools that make a compass useful: magnetic, true and grid north, bearings and distances to saved places, a position from two bearings, the Sun, the Moon, the pole star and the Qibla, a world map with the magnetic declination and a converter for every common coordinate format.
Q2: How much does it cost?
A2: Nothing. It is free, with no registration and no limit. Like every page on ZeroDataUpload, it is supported by advertising.
Q3: Do I need to install anything or create an account?
A3: No. Open the page in a modern browser (Chrome, Edge, Firefox, Safari or Opera) on a phone, tablet or computer. Your place, saved places and settings are kept in that browser, so there is nothing to sign in to.
Q4: Is anything I do uploaded?
A4: No. Every bearing, distance and position is worked out in your browser, and your place, saved places and settings stay on your device and are never sent to a server. The camera picture in Sight is shown on your screen only. The page itself loads the site's ads and analytics, as every page on the site does; the Privacy Policy explains those, and what you do in the tool is never part of them.
Q5: Does it work without an internet connection?
A5: The page needs a connection to load. Once it is open, the compass, the calculators, the sky and the map keep working without one: the magnetic model, the astronomy, the land outline and the list of towns are part of the page.
Q6: How is this different from Sun and Moon?
A6: Sun and Moon is a calendar of the sky: sunrise, sunset, twilight, moon phases, eclipses and the panchang for any day. CompassPro is a compass. Its Sky tab shows the same sunrise and sunset, worked out with the same astronomy, but turns them into directions: where the Sun and the Moon stand on the dial, when the Sun lies in the Qibla direction and how to find north from the Sun, a watch or the pole star.
2. The Compass
Q7: How do I use it on a phone?
A7: Hold the phone flat, top edge pointing ahead. The card turns like a real compass: the red pointer is north and the mark at the top of the dial is where your phone points, with the heading in large figures beside it. Tilting the phone does not throw the reading off, and held upright the phone reads the direction the camera faces.
Q8: Why does my iPhone ask before the compass starts?
A8: Safari on iPhones and iPads only lets a page read the motion and orientation sensors after you tap and agree. Tap Start the compass and allow access when asked. If you said no, allow it again in Safari's settings for the site, or turn the dial by hand.
Q9: Does the compass work on a computer?
A9: Most computers have no compass sensor, and the page says so instead of showing a needle that does not move. Drag the dial, or click it and use the arrow keys, to set the direction you face; every other part of the tool works as on a phone.
Q10: How accurate is a phone compass?
A10: A phone measures the Earth's magnetic field with a small sensor, and steel, magnets, cars, speakers and phone cases with magnets can pull it off by several degrees. Step away from metal, calibrate it and check the heading against a direction you know, such as a straight street on a map. For anything where an error matters, carry a real compass as well.
Q11: How do I calibrate the compass?
A11: Press Calibrate for the steps: step away from metal, draw a large figure 8 in the air three times while turning your wrist, then lay the phone flat and check it against a known direction. On an iPhone the page also shows how sure the phone says its compass is.
Q12: What do Hold, Keep screen on and Night light do?
A12: Hold freezes the reading so you can lower the phone and read it (press again to let go). Keep screen on stops the screen from sleeping while the page is open, where the browser allows it. Night light turns the tool red on black, which keeps your eyes used to the dark; use it with the site's dark theme for the darkest screen.
Q13: Can it read the heading aloud?
A13: Tap the heading figures and the page reads the heading and the direction with a voice that runs on your device. If your device has no such voice, the page says so and only shows the heading; it never sends the text to an online voice.
3. North and the Magnetic Field
Q14: What is the difference between magnetic, true and grid north?
A14: Magnetic north is where a compass needle points. True north is the direction of the North Pole. Grid north is the up direction of a UTM or MGRS map grid. Pick one with the buttons under the heading; every bearing on the page follows it, and the facts under the dial show the angles between them at your place.
Q15: What is the declination and where does it come from?
A15: The declination is the angle between magnetic and true north at a place. CompassPro works it out for your place and today's date from the World Magnetic Model 2025 of NOAA and the British Geological Survey, the model phones and navigation systems use. It carries the model's own figures, valid from 2025 to the end of 2029, and the facts also show how fast the declination is changing each year.
Q16: Why does true north need my place?
A16: The declination changes from place to place: in parts of the world it is zero, elsewhere it is twenty degrees or more. Until you choose a place, the page shows magnetic north only, and the True and Grid buttons ask for your place first.
Q17: What is the grid convergence?
A17: A map with a kilometre grid flattens the Earth, so its grid lines lean a little away from true north, more so towards the edge of each UTM zone. That lean is the grid convergence. Use Grid when you take bearings off a paper map with a kilometre grid, and the bearings match the map.
Q18: Does the compass work near the North or South Pole?
A18: Close to the magnetic poles the field points almost straight down, so the part a compass uses is weak. NOAA marks areas where compasses may not be fully accurate and, nearer the poles, areas where they are unreliable and the declination is not accurate. The facts under the dial and the field on the Map tab say so when your place is in one of them.
4. Places and Navigation
Q19: Why does it not use my location?
A19: Location is turned off for this page, as for every page of zerodataupload.com except the GPS Speedometer, so the compass cannot ask your browser where you are. Choose a town from the list, type coordinates in any common format, pick a point on the map or work out your position from two bearings. The compass itself does not need your location; your place is only needed for true north, the Sun, the Moon, the Qibla and distances.
Q20: How do I choose my place?
A20: Press the place button above the tabs. Search the list of about 200 towns and cities, or open Type coordinates and enter any format, with a name if you like. You can also pick a point on the Map tab (Make this my place) or use a position fix from Work it out on the Navigate tab.
Q21: How do saved places work?
A21: On the Navigate tab, Save my place keeps your chosen place, and Add saves any place from coordinates. Each saved place shows its bearing and distance from your place, with buttons to go there, share it, edit it or delete it (Undo in the message). Up to 500 places are kept, with names of up to 80 characters.
Q22: How do I walk to a saved place?
A22: Press Go here on the place. Going to shows its bearing and distance from your place, and a magenta diamond marks it on the compass card. Turn until the diamond is under the mark at the top of the dial, or press Follow this bearing to lock that bearing in. Because location is off for this page, the distance counts from the place you chose; change your place as you go.
Q23: What do Follow this bearing and Way back do?
A23: Follow this bearing locks the direction you face as your course: a magenta line marks it on the card and the panel says how far to turn left or right, with the way back beneath it. You can also type a course. Way back follows the reverse of the direction you face now, for returning the way you came.
Q24: Can I load or save places as a GPX file?
A24: Yes. The download button saves your places as a GPX file, the format hiking apps and GPS units use. The upload button reads the waypoints and route points of a GPX file (up to 5 MB), adds the new ones and skips the ones you already have. A file that holds only a recorded track has no places to add.
Q25: How do I share a place?
A25: Press the share button on a saved place. On a phone the phone's own share sheet opens; elsewhere a link to the place is copied. The place rides in the part of the link after the # sign, which browsers do not send to a server, and the page takes it off the address bar as soon as it opens. Someone who opens the link sees it as a destination for that visit and can press Save it to keep it.
Q26: How do I find where I am from two bearings?
A26: On the Navigate tab open Work it out and choose Where am I. Type two places you can see and know, such as a peak and a mast, and the bearing from you to each, or press Use compass while you face each one. Your position is where the two lines cross; lines that cross near a right angle give the best fix, and the page says how far a two degree error would move it.
Q27: How accurate are the distances and bearings?
A27: They are worked out on the WGS84 ellipsoid, the shape of the Earth GPS uses, and in our checks they agreed with an independent geodesy reference to within a millimetre, also for places on nearly opposite sides of the Earth. The Constant bearing line in Work it out is a rhumb line on a round Earth, easier to steer and a little longer.
5. Sky, Map and Tools
Q28: How does it find the Qibla?
A28: The Qibla is the direction of the Kaaba in Mecca along the shortest path over the Earth's surface, worked out from your place on the WGS84 ellipsoid. Turn on Qibla under the dial to see it as a green square on the card, or open the Sky tab for its bearing from true and magnetic north and its distance.
Q29: What are the Sun in the Qibla direction and the Sun over the Kaaba?
A29: On most days the Sun passes through the Qibla direction at a certain time; facing the Sun then faces the Qibla, and an upright stick's shadow points the way at the opposite time. Twice a year, in late May and in mid July, the Sun stands straight over the Kaaba at noon in Mecca; wherever it is day at that moment, facing the Sun faces the Kaaba. The Sky tab gives these times for your place.
Q30: How can I find north without a compass?
A30: The Sky tab lists the ways for your place and time: where true north lies when you face the Sun, the moment of solar noon when a shadow points due north or due south, how to use a watch with your local solar noon in place of 12 o'clock, and where Polaris stands from true north (in the southern hemisphere, how to find the south pole of the sky from the Southern Cross).
Q31: What does the world map show?
A31: From my place draws the world centred on your place, so every straight line from the centre is a true bearing and the distance from the centre is the real distance. Whole world shows the familiar flat map. Both can show the lines of equal magnetic declination, the night side of the Earth, the routes to your destination and to the Kaaba, your saved places and the towns of the list. Tap a point to see its bearing, distance and magnetic field.
Q32: Which coordinate formats does it read?
A32: Decimal degrees, degrees and minutes, degrees, minutes and seconds (with N, S, E and W or signs), UTM, MGRS, full and short plus codes, and links from map sites. The Coordinates tool shows the same place in all six formats, each with a copy button, and Settings chooses the format the page uses everywhere.
Q33: How does Measure a height work?
A33: Stand a known distance from a tree or building and type the distance, the angle up to its top and your eye height; the page works out the height. On a phone, aim the top edge at the top of it and press Use tilt to take the angle from the tilt sensors.
Q34: What is Point to it?
A34: A game for learning directions: eight rounds of up to 100 points each. Directions asks you to face a compass point or a bearing; Towns asks you to point to a town more than 300 km away. Turn to face it (or drag the dial on a computer) and press Lock in; your best score is kept.
Q35: What is Sight?
A35: Sight shows the camera picture with a strip of bearings across the top and a ring in the middle. Hold the phone upright, put a hill or a mast in the ring and read its bearing, then press Take bearing to note it or Follow it to follow it. The Sun, the Moon, the Qibla and your destination are marked when they are in view. The picture is never recorded or uploaded, and the camera turns off when you close Sight.
6. Settings, Data and Keys
Q36: What can I change in Settings?
A36: Bearings in degrees or mils (6,400 to the circle), distances in kilometres, miles or nautical miles, the coordinate format, whether the card turns like a real compass or north stays up with a turning pointer, how steady the needle is, and whether the phone vibrates when you are on course and as you pass north. The light or dark look follows the site's theme button.
Q37: What are the keyboard shortcuts?
A37: While you use the tool and are not typing: H holds the reading, F follows the current bearing and N switches between magnetic, true and grid north. On the dial without a compass sensor, the arrow keys turn it by 1 degree and Page Up and Page Down by 10. Elsewhere on the page these keys do what they always do.
Q38: Where is my data kept, and how do I delete it?
A38: Your place, saved places, destination, game scores and settings are kept in this browser on this device; nothing is saved on a first visit until you change something. Delete everything, under Settings, removes them after you confirm, and leaves the rest of the site alone.
Still have a question?
The help page walks through every part of CompassPro. For anything else, use the contact form.