Caliber Number — What This Mark Means
A manufacturer's identifier for the specific movement (mechanism) inside the watch. This number reveals the movement type, features, accuracy, and service requirements.
What This Usually Means
The caliber number identifies the exact movement powering your watch. It tells you whether the movement is quartz or mechanical, what complications it has (date, chronograph, GMT), its accuracy specifications, and its service interval. This is one of the most important technical identifiers on a watch.
Where to Find It
Often engraved or printed on the case back, on the movement itself (visible through an exhibition case back or when opened), or encoded within the model number. Seiko, for example, places the caliber as the first part of the case back number (e.g., "4R36" in 4R36-07G0).
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Common Variations
Each manufacturer uses its own naming scheme. Seiko uses alphanumeric codes like NH35, 4R36, 6R35. Citizen/Miyota uses numbers like 9015, 8215. ETA uses codes like 2824-2, 7750. Higher numbers don't necessarily mean higher quality.
Common Misconceptions
People often assume higher caliber numbers indicate better quality, but numbering systems are arbitrary and brand-specific. Also, the same base caliber may appear under different names when used by different brands (e.g., Seiko NH35 and SII NH35 are the same).
What to Do Next
Search the caliber number online to find detailed specifications including beat rate, power reserve, accuracy rating, and service intervals. This information is valuable for understanding your watch's capabilities and maintenance needs.
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Related Markings
An alphanumeric code stamped on the case back that identifies the specific watch model or product line. This number is e
Jewel Count MarkingA marking indicating the number of jewels (synthetic rubies) used as bearings in the movement. This number reflects move
Movement Country of OriginA marking indicating where the watch movement was manufactured, such as "Swiss" or "Japan." This identifies the movement
Commonly Seen On
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Frequently asked questions
Where can I find my watch's caliber number?
Check the case back, the movement itself through an exhibition back, or look up your model number online. It's often the first part of the case back reference.
What does the caliber number tell me?
It identifies the movement type, features, accuracy specs, beat rate, power reserve, and service requirements.
Does a higher caliber number mean better quality?
No. Numbering systems are arbitrary and manufacturer-specific. Quality depends on the movement's actual specifications.
Can different brands use the same caliber?
Yes. Movement manufacturers like ETA, Miyota, and Seiko supply calibers to many brands, sometimes under the brand's own caliber designation.
How do I know if my caliber is quartz or mechanical?
Searching the caliber number online will reveal this. Generally, quartz movements tick once per second, while mechanical movements have a sweeping second hand.
Does caliber affect service cost?
Yes. More complex calibers with chronograph or GMT complications typically cost more to service than simple three-hand movements.