The Watch Guide: Movements, Accuracy, Water Resistance and Spotting Fakes
How a watch works, what its markings promise, and whether it’s real.
Updated
The words on a dial — automatic, chronometer, 200 m — are claims. These guides explain what each one actually promises, then how to check the watch itself against those promises when its authenticity or value is in question.
How watches work
Movements, complications, and what the dial is telling you.
- Watch Movements Explained: Automatic, Quartz, Mechanical The movement is the engine of a watch — and the biggest clue to how it works, what it’s worth, and how to care for it. Quartz vs mechanical vs automatic, in plain English.
- Chronograph vs Chronometer: What the Words Really Mean They sound almost identical but mean completely different things. A chronograph is a built-in stopwatch; a chronometer is a certified-accurate movement. Here’s the difference.
- Why Your Watch Runs Fast (and What Accuracy Is Normal) Mechanical watches gain and lose seconds every day. Learn what rate is normal, how to measure yours properly, and whether it needs regulating or servicing.
- What 30m, 100m and 200m Water Resistance Actually Mean A 50m watch can die in a swimming pool. Learn how water resistance is really tested, which activities each rating survives, and why the rating expires with age.
Real, fake and valuable
Authentication checks and the factors collectors pay for.
- How to Tell If a Luxury Watch Is Real: A Spotter’s Guide Fake watches are better than ever. Learn how to spot a replica — the movement, weight, dial, and serial checks experts use — and how to identify any watch from a photo.
- How to Spot a Fake Rolex: The Tells That Still Work Counterfeit Rolexes have gotten frighteningly good, but real ones give themselves away. Learn the movement, weight, dial, and cyclops checks — and how to ID any watch from a photo.
- What Makes a Watch Valuable? A Collector’s Guide Brand, rarity, condition, and provenance turn a watch into an investment. Learn what really drives a timepiece’s value — and what to check before you buy or sell.
- The Most Iconic Luxury Watches Ever Made The Submariner, the Royal Oak, the Speedmaster, the Nautilus — a few watches defined modern watchmaking. The stories behind the icons, and how to identify and value any watch.
Tools for this topic
The essentials
| Term | Means | Doesn’t mean |
|---|---|---|
| Automatic | Self-winding mechanical movement | More accurate than quartz |
| Chronometer | Certified accurate (COSC −4/+6 s/day) | Has a stopwatch |
| Chronograph | Built-in stopwatch | Certified accurate |
| Water resistant 100 m | Passed a static pressure test; fine for swimming | Safe to dive to 100 m |
| DIVER’S 200 m | Meets the ISO 6425 diving standard | Safe in a sauna or hot tub |
Frequently asked questions
How accurate should a mechanical watch be?
Roughly −10 to +20 seconds a day is normal for a healthy mechanical watch; certified chronometers are tested to −4/+6 seconds a day.
Can I swim with a 50 m watch?
It is not recommended. Choose at least 100 m for regular swimming, with the crown fully closed.
How can I tell if a Rolex is real?
Check the sweeping seconds hand, the Cyclops magnification, crisp rehaut engraving, weight and finishing, and matching serials — and have a Rolex service center or experienced watchmaker inspect the movement.
Do luxury watches hold their value?
Most do not. A small number of in-demand models from brands such as Rolex, Patek Philippe and Audemars Piguet can hold or exceed retail.
What is the difference between quartz and automatic?
Quartz runs on a battery and a crystal oscillator and ticks each second; automatic is mechanical, wound by a rotor as you move, with a sweeping seconds hand.
Sources and further reading
- COSC — Swiss Official Chronometer Testing Institute — COSC
- Counterfeiting — Federation of the Swiss Watch Industry FH
- Swiss made — Federation of the Swiss Watch Industry FH
- Chronometer watch — Wikipedia
- Water Resistant mark — Wikipedia
Links checked September 14, 2026.