Buying well · 2 min read

How to read a watch spec sheet and spot what matters.

A good spec sheet answers four questions: will it fit, what powers it, how well is it built, and what can you do with it. Start with diameter, lug-to-lug and thickness for fit, then check the movement, crystal and water resistance. Note what the seller does not publish, because gaps are information too.

Fit: the four measurements.

  • Diameter: the case width, usually without the crown.
  • Lug-to-lug: the length along the wrist. It often matters more than diameter. Lug-to-lug explained.
  • Thickness: how tall the watch sits, including the crystal.
  • Lug width: the strap width at the lugs, which decides which straps fit.

Power: movement and reserve.

The spec should say automatic, hand-wound, quartz or solar. For an automatic, the power reserve shows how long it runs unworn. Power reserve explained.

Build: crystal, material and water resistance.

Sapphire resists scratches better than mineral glass. Water resistance ratings are a lab specification rather than a diving promise. Crystal types and water resistance explained cover the details.

What the sheet might leave out.

Many brands do not publish lug-to-lug or lug width, and some do not publish a power reserve or dive certification. On Watch Ritual, we show these as not published instead of guessing. If a missing figure matters to you, ask the seller before you order.

Check the source.

Prefer the manufacturer’s own page for specs, and compare it with the retailer’s listing; if they disagree, trust the manufacturer. Our reviews note which figures come from which source.

Watches with full published specs.

A few good questions.

What is the most important watch measurement?

For fit, lug-to-lug span and thickness matter at least as much as diameter.

What does a sapphire crystal mean on a spec sheet?

A scratch-resistant crystal. Some brands add anti-reflective coating on one or both sides.

What is power reserve?

How long an automatic or hand-wound watch runs when fully wound and not worn.

Why do some brands not publish lug-to-lug?

Some only list diameter and thickness. If it matters, ask the seller or compare with your own watch.

How we write guides: we explain watchmaking from manufacturer documentation and published standards, and say plainly where numbers vary by brand or movement. Our approach.