How to Tell If Your Watch Is Magnetized (and How to Demagnetize It)
If your mechanical watch suddenly gains minutes a day instead of seconds, there's a good chance it isn't broken at all: it's magnetized. Phones, laptops and bag clasps are full of magnets. The good news is that magnetism is easy to test for at home and takes seconds to fix. Here's how.
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Why magnetism makes a watch run fast
A mechanical watch keeps time with a balance wheel and a hairspring that "breathes" in and out several times a second. Most hairsprings are made of a steel alloy. If they're exposed to a strong magnetic field, the coils become slightly magnetic and cling to each other. The spring then behaves as if it were shorter, so it oscillates faster, and the watch gains time.
Signs your watch is magnetized
- It suddenly gains a lot: a minute or more per day when it used to be within seconds.
- The change happened overnight, often after you put it next to a laptop, speaker or phone.
- The rate is erratic: fast one day, very fast the next.
- In extreme cases it stops because the coils stick so hard the balance can't swing.
A watch that gains 10–20 seconds a day is probably not magnetized; that's normal for many affordable movements. Our guide to an automatic watch running fast covers the other causes.
The compass test
- Lay a simple magnetic compass flat on a table. A phone compass app works too, but keep the watch from touching the phone.
- Wait until the needle settles.
- Slowly move the watch around the compass, about 1–2 cm away, especially near the 6 and 12 o'clock sides.
- If the needle twitches or swings as the watch passes, the watch is magnetized.
A steel case and bracelet can make the needle move slightly on their own, so look for a clear jump rather than a tiny wobble. Timing apps that listen to the tick (timegrapher apps) can also show a sudden, large gain.
How to demagnetize a watch
A watch demagnetizer is a small box, usually blue, that creates an alternating magnetic field. They are inexpensive and widely sold online. To use one:
- Take the watch off and remove any magnetic items nearby.
- Place the watch flat on the demagnetizer.
- Press and hold the button.
- While still holding the button, slowly lift the watch straight away until it's about 30 cm (a foot) from the device.
- Only then release the button. Releasing it while the watch is on the device can leave it magnetized again.
- Repeat the compass test. If it still reacts, repeat once or twice with the watch in a different orientation.
Afterwards, reset the time and watch the rate for a day. Remember to set the date safely: our date-setting guide explains the danger zone. No demagnetizer? Most watch repair shops will do it in a minute, often for free.
Common magnet sources to avoid
| Source | Why it's a risk |
|---|---|
| Laptop and tablet lids, smart covers | Strong magnets hold the lid closed, right where your wrist rests |
| Phone speakers, magnetic phone cases and chargers | Close contact when you set the watch down next to the phone |
| Bag and handbag clasps | Often powerful magnets |
| Speakers and headphones | Large magnets in the drivers |
| Induction hobs, fridge magnets, some watch boxes | Strong fields at close range |
Distance is your friend: magnetic fields weaken quickly. Keep the watch 10 cm or more from these sources when you take it off.
Common questions
Does magnetism damage a watch permanently?
Almost never. Once demagnetized, the watch returns to its usual rate. Only in rare cases, such as a hairspring tangled by a strong magnet, does it need a watchmaker.
Are some watches anti-magnetic?
Yes. Many watches meet the ISO 764 standard, which requires resistance to a field of 4,800 A/m (about 60 gauss). Modern hairsprings made of silicon or special alloys resist far stronger fields; several Swiss brands now use them in mid-priced watches.
Can quartz watches get magnetized?
A strong field can stop or disturb the stepping motor of a quartz watch while it's exposed, but it usually recovers once moved away.
How often should I check?
Only when the rate suddenly changes. There is no need to demagnetize a watch as routine.
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