Watches - Feature Article

How does magnetism affect a watch?

We look at what causes magnetism in a watch, what effect it has, how to avoid or resolve it, and a handful of the best anti-magnetic watches out there.

After more than 250 years of progress in horology, magnetism is still the most common cause for a mechanical watch to stop keeping time. A slight charge passed onto a watch can cause it to run a few seconds fast, a medium charge and we’re talking minutes. Of course, top brands are now making headway and there are a few fully anti-magnetic mechanical watches available, but it’s not as easy to combat as you might think.

Magnetism has been the number one enemy to clocks and watches since they first hit the scene. In the days when a watch was a central piece of kit for pilots, racecar drivers or everyday folk, a magnetised watch was a major spanner in the works. Nowadays, digital clocks have resolved the issue, but those who wear and appreciate mechanical watches will still want to keep them working well and make sure they aren’t being damaged.

how does magnetism affect a watch?

What can cause magnetism in a watch?

With the proliferation of electronic devices, watches are frequently picking up a charge. Phones, hairdryers, TVs, these can all pass on a small magnetic field. Placing your watch next to a digital alarm clock overnight is enough to make it run a few seconds fast. But devices such as microwaves, MRI scanners, large stereos and X-rays emit much stronger charges. Pilots, medical staff and electricians are often the most affected.

What effects does magnetism have on your watch?

Most watch movements are made up of tiny steel components. More often than not, magnetism will cause a watch to gain time, but it can also cause it to lose time or potentially stop. A medium to strong charge will pull these pieces in different directions, potentially slowing down cogs or bringing them to a halt.

The balance spring, or hairspring as it’s also known, is usually the key cause for concern. It’s a tiny, delicate coiled spring that causes a wheel to pulse back and forth, typically at a rate of about 28,000 beats per hour. This energy is then distributed throughout the movement via intricate cogs and levers, which drive the hands and power any complications. Any small amount of charge on the balance spring can shorten its swings and so speed up its frequency.

Generally speaking magnetism won’t damage a watch’s components, but a large dose can put extra stress on parts and could potentially distort them.

silicone watch movement anti magnetic

How to test for magnetism?

If your watch is running fast the most likely cause is magnetism. Place it next to a compass and you may see the needle turn towards your watch. The most efficient way to test it is to remove the case back and hold the compass over the balance spring or wheels. This job might best be done by a watchmaker.

How to demagnetise a watch?

By far the most efficient way to demagnetise a watch is with a demagnetising machine. It’s a small device, about the size of a cigarette packet, which emits an irregular magnetic field that effectively neutralises the charge in your device. You can pick them up from Amazon for under £10. Although you can do it yourself, it is recommended to send it in to a watchmaker, who can remove the case back and check for any potential damage.

There are other ways to demagnetise a magnetised device. Inflicting a shock works well—watchmakers often bang their tweezers on the side of the desk to knock out the charge—but for obvious reasons this isn’t ideal for your watch. The other way is to expose it to a very high heat, which again is not recommended.

What are the best anti-magnetic watches?

It’s only really in recent years that antimagnetic technology has taken off. One of the early pioneers of the antimagnetic wristwatch was IWC, who released the Mark II in 1948. IWC fitted a layer of iron around the movement, which effectively shielded it, but it also added a fair amount of weight to the watch. Today IWC’s Ingenieur range has some excellent examples.

Rolex and Omega soon took on the idea and joined the race with the Milgauss and the Railmaster. The Milgauss was made specifically for CERN scientists who were working around strong magnetic fields. 

anti-magnetic luxury watches

New technology has come into play in the past decade. Watchmakers are now able to make parts from silicon and other materials that don’t pick up a charge. Recent Rolex models and a number of Omegas are now incorporating silicon parts in many of their movements and developing their anti-magnetic models to a very high level. There are many other brands in the race that have made excellent examples, amongst them are Ball and Bremont.

By far the most antimagnetic watch available is Omega’s Aqua Terra, which is an impressive fifteen times more antimagnetic than the Milgauss. Omega plans to roll out this technology to all their watches by 2017.

Chances are, unless you work in an environment in which you're exposed to high doses of magnetism, you're not going to be damaging your watch. Regardless, if you're watch is running fast then it's worth investigating.

In this case, the recommend action is to send it in to a watchmaker, who can also ensure any damage or malfunction is addressed. If you're interested in learning more about servicing and watchmaking, check out our articles describing what goes on in a watch service or a watch refurbishment.


If you're looking to browse unworn, pre-owned and vintage watches including the above mentioned brands and models, click here.