An automatic watch is a small machine that runs on the motion of your wrist. It needs a little more attention than a battery watch, but not much. Here's how it works, how to wind and set it, and how to keep it running for years.
How an automatic watch works
Inside the watch, a mainspring stores energy. A weighted half-circle called a rotor spins as you move your wrist and winds that spring. The spring releases its energy slowly through a series of gears, regulated by a balance wheel that swings back and forth several times a second. That's why the seconds hand sweeps smoothly instead of ticking once a second. On a skeleton watch, you can watch all of this happen.
A fully wound automatic typically runs for around a day and a half to two days off the wrist before it stops. This is called the power reserve.
How to wind it
If you wear the watch daily, you don't need to wind it at all. If it has stopped, or you're putting it on for the first time:
- Take the watch off your wrist.
- With the crown pushed in (or unscrewed to its first position on a screw-down crown), turn it clockwise, away from you, 20 to 30 times. You'll feel a smooth, light resistance.
- The seconds hand will start moving. Set the time and put it on.
A gentle shake also gets it going, but a few turns of the crown gives it a fuller start. Most modern automatics can't be overwound, because a slipping clutch stops the spring from being wound too tight.
How to set the time and date
Most automatic watches with a date have three crown positions:
- Position 0 (pushed in): winding.
- Position 1 (pulled out one click): quick-set the date (and the day, on a day-date, usually by turning the other way).
- Position 2 (pulled out fully): set the time. On many movements the seconds hand stops here so you can set the time to the second.
Important: avoid quick-setting the date when the time shows between about 9pm and 3am. During those hours the date-change gears are engaged, and forcing them can damage the movement. Move the hands to around 6 o'clock first, set the date, then set the time. Remember to check AM or PM: the date flips at midnight, so if it changes at noon, move the hands forward 12 hours.
Finally, push the crown back in (and screw it down if it's a screw-down crown) before the watch gets anywhere near water.
What accuracy to expect
Automatic watches are less accurate than quartz. Affordable automatic movements commonly gain or lose several seconds a day, which adds up to a minute or two a week. That's normal. Most owners reset the time every week or two. Accuracy can shift depending on how the watch sits overnight: lying face up, on its side or crown down can each change the rate slightly, so you can experiment to cancel out drift.
If it suddenly starts gaining many minutes a day, it may have been magnetized. Keep reading.
Everyday care
- Magnets: keep the watch away from strong magnets like speaker magnets, magnetic phone mounts and tablet covers. A magnetized watch usually runs very fast. A watch shop can demagnetize it in seconds.
- Water: check the water resistance rating, keep the crown pushed in or screwed down, avoid hot showers and saunas, and rinse in fresh water after salt water or a pool. See what water resistance ratings mean.
- Shocks: automatics handle normal life fine, but hard knocks, like golf or hammering, can upset the balance. Take it off for heavy impact sports.
- Cleaning: wipe the case and crystal with a soft microfiber cloth. For a dirty bracelet, use a soft toothbrush with warm water and a drop of mild soap, as long as the watch is water resistant and the crown is closed, then dry it thoroughly.
- Storage: keep it in its box or a watch case away from heat and direct sunlight. A watch winder is optional; letting an automatic stop when you're not wearing it doesn't hurt it.
Servicing
Over time, the oils inside the movement dry out. Every few years, or if the watch starts losing a lot of time, stops early or feels rough when winding, have it serviced by a watch repair shop. A service cleans, oils and regulates the movement so it can keep running for decades.
Related guides
- How to choose an automatic mod watch under $300
- How to size a watch bracelet at home
- NH35 vs NH36: the movements behind most mods
Frequently asked questions
How long does an automatic watch run without being worn?
Typically around a day and a half to two days when fully wound. After that it stops and needs a few turns of the crown to restart.
Can you overwind an automatic watch?
Most modern automatics have a slipping mechanism that prevents overwinding, so you can't damage it by winding too much. Just wind gently.
Do I need a watch winder?
No. A winder is a convenience that keeps the watch running so you don't have to reset it. Letting an automatic stop doesn't harm it.
Why is my automatic watch running fast?
A few seconds a day is normal. If it suddenly gains minutes a day, it has probably been magnetized. A watch shop can demagnetize it quickly and cheaply.