What Is an Automatic Watch, and How Do They Work?

Written by Paul Morrison
| Last Updated on May 11, 2021

There are many types of watches, many of them with different watch movements.

In this article, we’re going to take a look at the most popular watch type: automatic movement watches. These are also called automatic self-winding watches.

These watches, as the name suggests, wind themselves and are fully automatic watches. But how does it work? And are they any good?

Let’s take a look at it.

What is an automatic watch

What Is an Automatic Watch?

An automatic watch is a watch, that winds itself up automatically. It is an off-spring of the classic mechanical watch, where you have to turn the crown to wind up the clock. Instead of hand-power, it runs on kinetic power from the wearer’s movement. This power is then stored in the mainspring, and the power is later utilized to keep the watch running.

Simply put, it’s a non-battery watch that never runs out. Unless you stop moving or take off the watch for too long.

The automatic wrist watch is probably the most popular of all the watch movement types, as you never have to do anything else than wear the watch for it to work. These automatic self-wind watches come in all shapes, sizes, and prices, so you have a lot of options when it comes to the shopping part (which we will discuss later in the article).

How Do Automatic Watches Work

What makes a watch automatic?

Well, it’s the movement inside the watch, that makes it an automatic winding watch. The movement of a watch is what is powering the watch. The automatic mechanical movement is what keeps the watch going, as long as you wear it. Other types include manual mechanical, quartz, solar, and others.

Read along as we’ll take a deeper dive into the intricate build of an automatic timepiece.

Automatic Watch Movement

Automatic watch movement is based on the concept of kinetic energy to power the watch. Kinetic energy is defined as:

“Energy which a body possesses by virtue of being in motion.”

Which in everyday language means: “The energy you generate when you move around”. Automatic movements used in watches rely on your movement to power the watch. Winding an automatic wristwatch is therefore done by going about one’s day.

Diving a bit deeper into the technical aspect of the movement, automatic wristwatches are, just as manual mechanical watches, powered by a wound spring. In an automatic watch, there is an additional metal weight called a rotor. This rotor can rotate 360 degrees inside the watch. It is this rotor you are spinning when you move around. As the rotor rotates, it transfers the energy, automatically winding the mainspring until it is fully wound.


Automatic Watches Accuracy

An automatic watch consists of 100’s of small pieces, all put together in a tight case. This of course makes it difficult to achieve 100% accuracy. If a watch is just 1% off, making for 99% accuracy, you would be off by approximately 1 minute and 27 seconds every day – which is unacceptable when talking about luxury watches.

It’s therefore an incredible feat to keep these tiny pieces of machinery accurate.

When that’s said, here are the standards of an automatic movement watch:

Modern Mechanical non-COSC Certified watch

  • Bad: +/-10 seconds per day, 99.988% accuracy
  • Standard: +/-5 seconds per day, 99.994% accuracy
  • Great: +/-3 seconds per day, 99.996% accuracy

Modern Mechanical COSC Certified watch

  • Bad: +6/-4 seconds per day, 99.994% accuracy
  • Standard: +/-3 seconds per day, 99.996% accuracy
  • Great: +/-1 seconds per day, 99.998% accuracy

This again depends on position and temperature, so there are small deviations.

Hodinkee states that you should expect a Rolex to be within +2/-2 seconds per day, and expect Grand Seiko Hi-Beat movements to be within +5/-3 seconds per day.

How to Wind an Automatic Watch

We’ll keep this short. When you move around, you spin the rotor inside the watch, which will wind the mainspring until it is fully wound. When not worn, the mainspring will act as a power reserve.

How Long Do Automatic Watches Last

Automatic watches usually lasts 40-50 hours. This is also called the power reserve. For most this is enough, but if this is important to you, you can get some that stay wound for a lot longer. Some really high-quality watches can last for days, some even for weeks, so it does depend a lot on the manufacturer.

Make sure to ask the vendor before purchasing, if you’re looking for something extraordinary.

Automatic vs Quartz Watch

This matchup can be described very easily since Automatic versus quartz is basically Battery vs. No-Battery watches.

A quick way to identify an automatic mechanical watch is to watch the second hand. If it has a smooth, sweeping motion, instead of or a ticking motion, it’s mechanical.


The advantage of automatic watch movements over quartz is, that you never need to change a battery. The watch is slightly less accurate though (on average around 0,001%).

Automatic vs Mechanical Watch

A watch with automatic movement is technically also a mechanical watch, but in this instance, we refer to a manual mechanical watch, so to be technically correct this section should be called “automatic vs manual watch”.

The main difference here is the winding. A manual timepiece needs to be wound by hand, turning the crown to wind the mainspring. Winding an automatic watch is done by the watch itself as explained earlier in the article.

Automatic vs Kinetic Watches

Automatic and Kinetic watch movements are both automatic mechanisms. The difference lies in the method. Where the automatic timepiece winds a mainspring with a rotor (non-battery powered watches), the kinetic watch is equipped with oscillating weights that power a battery when it swings back and forth.

This means that kinetic timepieces need a battery, which has to be changed – though far less often than its quartz counterpart.

Are Automatic Watches Good?

Automatic watches are both good and bad. In general, they are very popular, because you don’t have to worry about your timepiece running out of time. On the other hand, these types of timepieces are generally less accurate, because of the active environment inside the watch.

When that is said, it all comes down to the company behind the watch. Some automatic watches are both built better, inside and out, and are more accurate than others. If you make sure to buy a quality automatic watch, you’ll be in a good spot.

What Automatic Watch Should You Buy?

There are plenty of watches out there – also in the automatic category. If you’re not sure what to buy, you can read through some of our other articles, where we compare some of the top watches in their respective category:

Here you will find both the best high-end automatic watches and the best cheap automatic watches.


What does “automatic watch” mean?

“Automatic watch” means that the watch is built with automatic movement. Also known as self-winding watches, an automatic watch is a mechanical watch that winds itself when you move around, so you don’t have to wind it up manually.

Can you overwind an automatic watch?

No, you can’t overwind an automatic watch. Watches with an automatic movement mechanism are designed to stop powering the mainspring as soon as the watch is fully charged.

How does a self-winding watch work?

An automatic watch works by powering itself, utilizing the kinetic energy the wearer generates by moving around. In short, it powers itself when you do everyday stuff. This power is stored in the mainspring. When you don’t move around, the watch then uses the stored up power.

Do automatic watches need batteries?

No, automatic watches don’t need batteries – that’s the best part! The automatic movement inside the watch generates its own power and stores it in the mainspring. This power is generated from you moving around. Automatic watches are non-battery watches.

How do you keep an automatic watch running?

To keep an automatic watch running, you just need to move around. The watch will power up from everyday activities, from waving your hand to shaking someone’s hand. Or you can just shake it a little bit.

About Paul Morrison

For years I’ve been buying and selling watches as a hobby, which led me to the decision of starting Watch for Tomorrow. I write a lot of the content, and I enjoy doing it. The most important aspect for me is the guidance of buying watches as well as avoiding bad ones. There are many bad watches out there, that are just too expensive. Hopefully, I can help you find your dream watch!