The Timepiece Journal » Swiss watchmaking

Everything you've ever wanted to know about COSC chronometer certification — answered clearly and concisely. From what the certificate means to whether it's worth paying for.

Ever received a chronometer certificate and wondered what all those numbers mean? This guide explains every field, every criterion, and what the data tells you about your watch movement.

Is a COSC chronometer certificate worth paying for? We break down what the certification actually tests, what it guarantees, and whether it matters for everyday wear.