True North Is Not Magnetic North Screensaver
The True North Is Not Magnetic North screensaver shows magnetic declination from NOAA's geomagnetic calculator, read live and key-less. It's free, runs in your browser, and ESC exits.
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Press ESC to leave fullscreen. Settings are saved in your browser only.
How the True North Is Not Magnetic North screensaver works
The saver reads the source described above and draws it on a canvas — no account, no tracking.
Magnetic declination from NOAA's geomagnetic calculator, read live and key-less. A compass points at the field, not the pole — about 20° west in Seattle, 15° east in Maine — and the drift is why charts and survey bearings have to be reissued.
It refreshes on a schedule, so what you see stays current.
Colours and any options can be changed in settings; nothing is stored beyond your own browser.
The World Magnetic Model behind declination
Magnetic declination is the angle between true north, the direction of the geographic pole, and the direction a compass needle points. It is positive when the needle points east of true north and negative when it points west. The value depends on where you are, and varies with time.
It is computed from a model of the Earth's main magnetic field such as the World Magnetic Model. The WMM was jointly developed by NOAA's National Centers for Environmental Information and the British Geological Survey, and is produced for the U.S. National Geospatial-Intelligence Agency and the UK Defence Geographic Centre. A new version is issued every five years: WMM2025 was released in December 2024 and is valid until the end of 2029. A calculator turns the model into a declination for a chosen latitude, longitude and date.
The main field is generated in the Earth's outer core, so it keeps changing, and the magnetic poles drift. That is why the line of zero declination shifts across continents and why charts and survey bearings must be revised. The WMM models only the main field and does not include crustal fields, so local anomalies from rock and mineral deposits are not represented.
A worked example
Magnetic declination from NOAA's geomagnetic calculator, read live and key-less. A compass points at the field, not the pole — about 20° west in Seattle, 15° east in Maine — and the drift is why charts and survey bearings have to be reissued.
Settings & tips
- Accent and Background recolour the display.
- Every value on screen comes from the live source — nothing is simulated.
- Press ESC to leave fullscreen.
Frequently asked questions
- Is this real data?
- Yes — it comes from the source named on this page and is refreshed on a schedule.
- Is a key needed?
- No. This source is fully key-less.
- Is it free?
- Yes, and it runs entirely in your browser.
- Do I need to correct my compass for declination?
- For precise navigation with a map, yes: adjust by the local declination. Many modern compasses and map apps allow you to set it.
- Why does the value change over time?
- The magnetic field is generated by motion in the Earth's core, so the field and the poles drift slowly; the model is reissued every five years to follow.