Binnacle: Compass & True North

Binnacle is a compass from Moonlet Labs that always tells you which north it is showing. It reads your phone's rotation sensor and works out true north with the World Magnetic Model 2025, which is built into the app.

True north or magnetic north
A compass needle points to magnetic north, not true north, and the difference depends on where you are. Binnacle uses your approximate location, or a city you choose, to work out that difference and show true north. Every heading is labelled "True north" or "Magnetic north", so you always know which one you are reading. Without a location or a city, Binnacle shows magnetic north and says so.

Hold a bearing
Tap Hold to lock a heading. A marker stays on the dial's edge, and Binnacle tells you how far to turn ("Turn 12° left") until you are on bearing. Hold the phone flat like a map compass, or upright to sight along it; Binnacle switches between the two by itself.

Calibration help
When the sensor needs it, Binnacle shows you how to calibrate: move the phone in a figure of eight, away from magnets, laptops and magnetic cases, while a live accuracy chip reads High, Medium or Low. The Accuracy screen explains in plain words what your phone's sensor can do, how far magnetic north is from true north where you are, which magnetic model Binnacle uses and how long it is valid, and interference. If a known landmark disagrees, a trim of up to 15° either way lines Binnacle up with it.

Interference warnings
Magnets, metal, laptops, cars and magnetic phone cases throw any phone compass off. Binnacle compares the magnetic field it measures with the field the model expects where you are, and warns you when something magnetic is nearby and readings may be wrong.

Qibla direction
The Qibla tool shows the direction to the Kaaba (great-circle) from your approximate location or a city you choose: a marker on the same dial, the bearing in degrees and how far to turn. When you face it, the dial turns green and, with haptics on, the phone gives a short buzz. Binnacle does not include prayer times.

What Binnacle is for
Binnacle is for finding your way around and lining things up; it is not a substitute for a baseplate compass where your safety depends on it. How close it gets depends on your phone's sensor and on what is around you. Binnacle needs a phone with a compass sensor (magnetometer). It remembers your last tool and your settings, and can keep the screen on while it is open.

Privacy: no account needed, and the compass works offline. Location is optional: Binnacle asks for your approximate location only when you choose true north or the Qibla, or tap Use my location, uses it on this phone only and never sends it. You can pick a city from a list built into the app instead (city data from GeoNames, CC BY 4.0). The app is ad-supported: ads are served by Google AdMob, which may use the advertising ID. Moonlet Labs collects crash reports and usage analytics through Google Firebase, linked to pseudonymous app identifiers rather than your name or email; they never include your location or your heading. Where the law requires it, the app asks for your consent first, and privacy choices are in Settings. Privacy policy: moonletlabs.com/privacy.html