There’s something mesmerising about the smooth, ticking motion of an automatic watch. Unlike a quartz watch that relies on a battery, an automatic timepiece is powered by the natural movement of the wearer’s wrist—no charging, no battery swaps, just pure mechanical brilliance.
These self winding watches have been around since the 18th century and are still favoured by collectors for their precise rhythm and handcrafted charm. But what exactly makes automatic watches tick? How can a spinning rotor and a few tiny gears keep time with such accuracy?
If you’ve ever stared at the intricate insides of a mechanical watch and thought, “How does this little machine actually work?”—you’re not alone.
In this guide, we’ll unpack how automatic watches work, the mechanical watch movements behind them, and how they stack up against quartz and manual watches. Trust us, it’s a fascinating world once you get a peek inside.
What Is an Automatic Watch?
An automatic watch—also called a self-winding watch—is a type of mechanical timepiece that winds itself as you wear it.
Rather than relying on a battery like a quartz watch, it draws power from the natural motion of your wrist. Every time the wearer moves, energy is generated and stored in the mainspring, the coiled heart of the watch, keeping it ticking with mechanical precision.
Inside the case, a small metal weight known as a rotor spins freely on ball bearings. This spinning rotor reacts to the movement of the wearer’s wrist, which then winds the mainspring gradually.
It’s a subtle but clever system that transforms kinetic energy into mechanical energy—eliminating the need to manually wind the watch every day.
What makes automatic watches especially practical is their “power reserve.” This refers to how long the watch keeps running after it’s taken off.
For most automatic watches, this ranges between 38 and 50 hours. Some high-end models, like those from Rolex or Omega, can stretch beyond that, offering longer reserves for wearers who rotate between different timepieces.
Part of the automatic watch’s appeal is more than just functionality—it’s also about prestige. You’ll often find this movement in luxury brands like Tag Heuer or Swiss-made classics, where the watch movement itself becomes a mark of craftsmanship.
The absence of a battery, the reliance on precision parts, and the self-winding mechanism all add to the sophistication that collectors admire.
Automatic watches may be powered by movement, but they’re driven by tradition, legacy, and an appreciation for fine mechanics.
Core Components of an Automatic Watch
Crack open the case of an automatic watch and you’ll find a miniature universe at work—tiny parts working in sync to turn motion into precise timekeeping.
Each component plays a crucial role, and together, they create the seamless ticking we’ve come to admire. So, what exactly lies beneath the surface?
At the heart of it all is the rotor—a semi-circular, freely spinning metal weight that reacts to the movement of the wearer’s wrist.
As the rotor spins, it winds the mainspring, storing energy without you even noticing. This is the very definition of a self winding watch: powered by your natural motion, not a battery.
Next, there’s the mainspring—think of it as the power source.
This tightly wound coil stores energy in the form of tension. The more it’s wound, the more energy is stored, ready to be gradually released to keep the watch ticking smoothly.
It’s this very mechanism that makes automatic watches both efficient and elegant.
But how does that stored energy move through the system?
Enter the gear train, a set of tiny gears that transfers energy from the mainspring to the escapement. Each tooth in this train is finely crafted to ensure precision in every turn.
Then comes the escapement, working closely with the balance wheel.
The escapement releases energy in exact, controlled bursts—like a gatekeeper that ensures the watch hands move in steady, precise increments. This regular pulse is what gives your watch its rhythm.
Speaking of rhythm, the balance wheel is the part that swings back and forth, dividing time into equal beats. Its motion—often compared to a pendulum—is essential for consistent accuracy.
Finally, we have the dial train and watch hands. These are the visible parts of the mechanism that display the time, powered by everything happening behind the scenes.
From the spinning rotor to the sweeping second hand, each part of an automatic movement works in harmony to make something extraordinary—mechanical timekeeping that doesn’t just tell time, but tells a story.
How Do Automatic Watches Work?
Imagine your wrist powering a tiny machine with every casual gesture—it’s not science fiction, it’s just how automatic watches work. Beneath the dial, there’s a fascinating dance of motion and mechanics, all triggered by something as simple as you going about your day.
The process begins with the rotor, a freely spinning metal weight attached to the movement. As your wrist shifts—even slightly—the rotor spins and winds the mainspring, which is the energy source for the entire watch.
This spiral mainspring holds elastic potential energy that keeps the watch alive long after you’ve stopped moving.
Once wound, that energy doesn’t just sit there.
It’s carefully channelled through the gear train, which acts like a highway system for power. The energy moves down the line, where the escapement and balance wheel take over.
The escapement ensures that energy is released in steady pulses, while the balance wheel swings back and forth in a precise rhythm. Together, they break time into consistent, measurable beats.
That’s why the second hand on an automatic watch doesn’t tick in sharp jumps like a quartz watch—it glides smoothly.
Most automatic watches operate at 6–8 beats per second, which gives them that signature sweeping motion. It’s one of the subtle features that sets mechanical timepieces apart and appeals so strongly to collectors.
But here’s the catch: if your watch isn’t worn regularly, it will eventually stop.
Most automatic watches have a power reserve that lasts 38–50 hours. So if you leave yours on the dresser for a couple of days, you’ll either need to manually wind it or use a watch winder to keep things moving.
The good news? Wearing your watch for just 8–10 hours a day is usually enough to keep it fully wound.
It’s a practical solution built into a highly detailed piece of craftsmanship—one that blends natural motion with old-world engineering in a way that still feels modern.
Do Automatic Watches Need Maintenance?
Owning an automatic watch isn’t just about wearing it—it’s about caring for a finely tuned machine.
Just like a classic car or a vintage record player, these mechanical timepieces need a little love to keep them running at their best.
Although automatic watches work through the natural movement of your wrist, they still need professional attention every 3 to 5 years.
Over time, the oils and lubricants that keep the gear train and other moving parts running smoothly begin to dry out. Without proper lubrication, friction builds up and can lead to wear that affects both timekeeping and the life of your watch.
A qualified watch repairer or Swiss watchmaker can service your timepiece by cleaning, oiling, and adjusting the mechanical movement to restore its precision.
This kind of maintenance helps preserve both performance and value—especially if you own a vintage or luxury model from a brand like Tag Heuer or Omega.
But care doesn’t stop at the workshop.
Day-to-day handling matters too. Automatic watches are more delicate than quartz watches, and they don’t like extremes. Avoid exposing them to strong magnets, sudden temperature changes, or high-pressure environments like hot tubs or saunas.
These elements can disrupt the delicate balance of the escape wheel, pallet fork, and balance wheel swings that regulate time.
If you’re not wearing your watch every day, it’s wise to store it properly. A soft, breathable cloth pouch or a vintage leather case works well. It should keep out dust while letting air flow around the watch—keeping moisture and mould at bay.
And don’t forget: even though it’s called a self winding watch, you may still need to manually wind it now and then—especially if it’s been sitting idle. A few turns of the crown can get things moving until the wearer’s movement takes over again.
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So, you’ve learned how automatic watches work—and maybe you’ve realised it’s time to let one go. Whether you’re planning an upgrade or simply want to unlock the value sitting on your wrist, SellMyWatch makes it easy to cash in with confidence.
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If your watch is sitting in a drawer instead of ticking on your wrist, why not let it work for you one last time?
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FAQs
Does an automatic watch stop when not in use?
Yes, an automatic watch will eventually stop if it isn’t worn for a while. Most have a power reserve of 38–50 hours, meaning they’ll keep ticking for about one to two days after being taken off. Once the stored energy runs out, the watch will stop until it’s either worn again or manually wound. If you’re not wearing it regularly, a watch winder can keep it running and maintain accuracy.
How long do automatic watches last?
With proper care and regular servicing, automatic watches can last for decades—sometimes even generations. Many vintage pieces still function beautifully today, thanks to solid mechanical watch movements and skilled maintenance. Getting it serviced every 3–5 years, keeping it away from magnets, and storing it properly will help extend its life significantly.
Is it OK to wear an automatic watch every day?
Absolutely—daily wear is actually great for keeping your automatic watch wound and working smoothly. The natural movement of your wrist keeps the rotor spinning and the mainspring charged. Just be mindful of exposure to extreme temperatures, water (unless it’s water-resistant), and magnetic fields, which can affect the movement’s accuracy over time.
What happens if an automatic watch runs out of power?
If your automatic watch stops due to lack of movement, there’s no need to panic. You can get it going again by gently winding the crown or simply wearing it for a few hours. Once the movement of the wearer’s wrist kicks in, the rotor spins and starts to store energy again, bringing the watch back to life.