Online Compass with True North

An online tool for finding your way outdoors: it shows the cardinal directions, your heading in degrees and any bearing you take, using the smartphone’s magnetic sensor. Unlike a plain needle it applies the local magnetic declination, so north lines up with your map instead of the magnetic pole. Works offline, with no app to install.

How to use it

1
Turn on the sensors

Open the page on a phone and tap “Turn on the compass”. On iOS 13 and later the browser asks once for motion and orientation access — allow it.

2
Calibrate the magnetometer

Trace a figure of eight in the air, turning the phone about every axis. The calibration segments fill in as the sensor sees new directions; it takes a few seconds.

3
Allow location

Coordinates are what make the declination correction and the sun and moon markers possible. Without them the compass still works, but it can only show magnetic north.

4
Hold the phone the right way

Flat, and the direction comes from the top edge of the screen, like a map. Lift it upright and the compass switches to sighting mode, reading the direction from the rear camera.

5
Take a bearing

Aim at your landmark and tap “Take current”. The deviation bar shows which way to turn, and the back bearing brings you back to where you started.

Find directions and hold a bearing using your phone’s sensors

Magnetic declination at a point

The correction between magnetic and true north — the number you write on a paper map. Computed on your device; no internet needed.

Features

True north from the WMM-2025 model, computed inside the browser
The magnetic pole sits well away from the geographic one — the gap reaches 11–14° across European Russia and passes 20° in Alaska. The whole World Magnetic Model ships with the page, so the correction works offline, and its output is checked against 100 NOAA reference points.
Sighting mode: aim the rear camera at a landmark like a real prismatic compass
Held upright, the usual heading calculation breaks down — the vertical axis degenerates. The compass switches to the camera axis and reports where you are actually pointing, with hysteresis so a shaking hand cannot make the needle flip.
A measured accuracy figure and a warning about magnetic interference
While the phone lies still the tool measures the spread of its own readings — that spread is the accuracy. If a motionless phone wanders by more than 8°, there is metal or a magnetic case nearby, and you are told, instead of trusting a steady but wrong needle.
Bearings, back bearings, a target by coordinates and a way-back marker
Take a bearing with one tap and the deviation bar shows which way to turn. The back bearing retraces your line, a target can be entered as coordinates with the distance computed, and a “car is here” marker turns the compass into a route home.
Sun and moon markers on the dial as an independent check
Their azimuths are computed astronomically, with no sensor and no network. If the sun marker parts company with the needle, the interference is visible at a glance. On devices without a magnetometer the same maths provides full sun-and-shadow orientation.
Night mode, screen kept awake, a buzz at each cardinal point and a spoken heading
Red rendering preserves dark-adapted vision, the screen stays on while you walk, a short vibration confirms north without looking, and the spoken heading helps when watching the screen is impractical.

Questions and answers

What is the difference between true and magnetic north?

Every compass needle points at the magnetic pole, while maps and GPS are built around the geographic one. The angle between them is the magnetic declination: about 11–12° east in Moscow, around 15° east in Seattle, over 20° in parts of Alaska. This compass computes the correction from the WMM-2025 model and keeps both figures separate.

Why does the compass not work on a computer?

The needle needs a magnetometer, and laptops and desktops do not have one. On such a device the page does not pretend to be a compass: it offers sun-based orientation and a declination calculator for any point, both of which work with no sensors at all.

The needle jumps or reads wrong — what should I do?

Usually the culprit is a magnet in a flip case, a car mount, a speaker or steel in the floor. Move a couple of metres away from metal and run the figure-of-eight calibration. If the readings drift by more than 8° while the phone is still, the tool tells you about it itself.

How accurate is a phone compass?

In a clean field a smartphone magnetometer settles around 2–5° after calibration, which is enough for hiking and for working with a map. The tool does not take that number on faith: it measures its own spread of readings and prints it next to the heading.

Does the compass work without internet?

Yes. The magnetic model, the astronomy and all of the logic live in the page, so after the first load the compass works offline. Coordinates come from the satellites, not from the network.

What is sighting mode for?

Taking a bearing on a distant landmark is easier with the phone raised to eye level, but in that pose the ordinary heading calculation degenerates: the vertical axis loses its direction and the needle spins on the slightest tilt. The compass detects the pose and switches to the rear-camera axis, so you aim the camera at the target like the sight of a prismatic compass.

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Who is this tool for?
🔌 Electronics Enthusiasts 🏃 Sports & Athletics ✈️ Travelers & Tourists
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