What Magnetisation Does to a Watch
A mechanical watch keeps time through the oscillation of a balance wheel — a weighted wheel controlled by a hairspring. The hairspring is the most delicate and critical component in the movement: a flat coil of metal typically made from a beryllium alloy or Nivarox steel, wound in a precise spiral. Its natural frequency determines how fast the movement beats, which determines timekeeping accuracy.
When a mechanical watch is exposed to a strong magnetic field, the coils of the hairspring can become magnetised. A magnetised hairspring tends to stick to itself — the individual coils attract each other instead of oscillating freely. This shortens the effective length of the spring, increases its frequency, and causes the watch to run fast. Depending on the degree of magnetisation, the effect can range from a few seconds per day to several minutes.
The critical point: there is no physical damage. The watch looks exactly the same. The problem is invisible without either testing or knowing where to look.
How Magnetisation Happens
The magnetic fields that cause watch magnetisation are everywhere in modern environments. The most common sources:
Bag clasps and handbag closures. Many modern bags use neodymium magnets as closures. These are strong enough to magnetise a watch placed next to them repeatedly.
Phone cases and tablet covers. Many cases contain magnets for closure or for attachment accessories. Resting a watch on a phone case overnight provides extended exposure.
Induction hobs. Electric induction cooking surfaces generate powerful electromagnetic fields. Leaving a watch near one while cooking can magnetise it rapidly.
Speakers and subwoofers. Older speakers and audio equipment use permanent magnets. Extended proximity to speaker cabinets is a common cause of magnetisation in watches stored on shelves near sound systems.
Airport security equipment and MRI machines. Airport body scanners are generally not strong enough to cause problems, but industrial magnetic equipment and MRI machines absolutely are.
How to Identify Magnetisation
The simplest test requires only a compass. Hold the watch near a compass needle. If the needle deflects significantly when you move the watch, the watch is magnetised. The compass doesn't need to be a specialised instrument — a basic hiking compass or even a compass app will show the deflection.
The symptoms — running fast, sometimes erratically — combined with a positive compass test are conclusive. No further diagnosis is needed.
How Demagnetisation Works
Demagnetisation is one of the few watch repairs that is genuinely simple and quick. It does not require opening the case, touching the movement, or any disassembly. The watch is passed through a demagnetiser — a device that produces an alternating magnetic field at decreasing intensity, which randomises the magnetic domains in the metal components and removes the magnetisation. The process takes about 5 seconds per pass and typically requires 2–3 passes.
After demagnetisation, the watch is tested against the compass again to confirm the field is gone, then observed for timekeeping over 24 hours. In cases where the magnetisation was severe and extended over a long period, there is occasionally residual frequency error from slight spring deformation — but this is rare and the demagnetisation itself resolves the magnetic component.
Service turnaround: Demagnetisation at Iglisi Watch takes minutes, not days. If this is the only fault, you can usually wait while it's done. Walk in, no appointment needed.
What Not to Do
Do not attempt to demagnetise a watch by holding it near another magnet or by waving it through the field of a fridge magnet. This does not demagnetise — it re-magnetises in a different orientation and makes the problem worse. The demagnetiser works by applying an alternating field; a static field from another magnet simply adds to the problem.
Anti-Magnetic Watches
Some watches are designed to resist magnetisation. The ISO 764 standard requires a watch to continue functioning within normal accuracy limits after exposure to a magnetic field of 4,800 A/m. This is achieved either by using a soft-iron inner cage around the movement (which shunts the magnetic field around the sensitive components) or by using non-magnetic materials for the hairspring (silicon, for example, is completely non-magnetic and is increasingly used in high-end movements for this reason).
Anti-magnetic certification does not mean immunity. Strong enough fields — MRI machine level — will magnetise anything. But for everyday magnetic sources, certified anti-magnetic watches are effectively immune.
Is Your Watch Running Fast for No Reason?
Magnetisation is one of the most common causes of unexplained timekeeping errors — and one of the easiest to fix. Bring your watch to our workshop in Durrës. We'll test and demagnetise it while you wait.
Rruga Aleksander Goga · Durrës 2001 · Albania · +355 67 636 0510
Published by Iglisi Watch · Durrës, Albania · April 2026. This guide covers watch magnetisation causes, identification, and the demagnetisation process.