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About this tool
Show heading and bearing from your device's magnetometer where supported.
Digital Compass is a browser compass that reads your device's orientation sensor and logs a heading in degrees, along with the raw alpha, beta and gamma angles behind it, each row timestamped. On iOS it uses the webkitCompassHeading value the magnetometer supplies; elsewhere it falls back to the alpha rotation of the DeviceOrientation event. It only runs after you tap start and grant sensor permission, and the readings stay on the phone — nothing is transmitted.
Open Digital Compass on AltFTool — it loads instantly in your browser.
Paste your code or data sample into the workspace.
Pick the format, conversion, or analysis you need.
Copy the polished result straight back into your project.
Every row shows alpha, beta and gamma next to the derived bearing, so you can tell a genuine reading from a tilted phone.
The last 200 readings are kept in a table with ISO timestamps instead of a single needle you have to watch live.
The orientation listener attaches only after you press start, and no heading, coordinate or timestamp leaves the browser.
Yes, on a phone with a magnetometer: the browser exposes the DeviceOrientation event, and this page converts it to a 0-360 degree heading. Desktop machines almost never have a magnetometer, so the reading will be missing or meaningless there.
Because iOS 13 and later require an explicit user gesture — DeviceOrientationEvent.requestPermission() is called when you press start, and Safari will not deliver a single orientation event until you accept. Nothing is logged before that tap.
Magnetic north. The page reports the sensor value as-is with no magnetic declination correction, and declination can exceed 20 degrees in parts of the world, so for surveying, aviation or navigation apply the local declination yourself or use an instrument that does.
Nearby metal and magnets are the usual cause — speakers, magnetic phone mounts, car dashboards, steel desks and laptop lids all distort the field. Hold the phone flat and away from metal, and if it stays wrong, recalibrate by moving the device in a figure-eight, which is what most phones' magnetometer calibration routine expects.