Frédéric Piguet Caliber 21

May 26, 2025

Frédéric Piguet Caliber 21 – A Masterpiece in Ultra-Flat Watchmaking

The Frédéric Piguet caliber 21 is a vintage 2-hander mechanical watch movement renowned for its ultra-flat design. With a thickness of just 1.73mm, this hand-wound movement is officially classified as ultra-thin and has become a symbol of fine Swiss watchmaking. Development of this caliber dates back to circa 1925.

Technical Highlights

frederic-piguet-calibre-21-movement-Oil Chart

Height: 1.73 mm
Manual winding (2-hand display)
Ultra-flat construction
Skeleton version: FP 21P
Highly decorated with boxed "21" engraving on some models

Watch Brands Using the FP21 Ebauche

Many prestigious brands have used the FP21 as a base movement, often adapting or rebranding it under their own caliber numbers:

Patek Philippe: Caliber 175, 177
Rolex: Caliber 650
IWC: Caliber 171
Omega: Caliber 700
Longines: Caliber 310
Certina: Caliber 20-10
Zenith: Caliber 53.5
MING: FP21.M1

Other brands using FP21 without specific caliber rebranding include:

Piaget
Blancpain
Cartier
Movado
Bueche Girod
Ebel
Bucherer

Movements Based on the FP21 Design

Audemars Piguet: Caliber 2003
Piaget: Caliber 9P
Vacheron Constantin: Caliber 1003
Jaeger-LeCoultre (JLC): Caliber 803

Legacy and Significance

The FP 21 has become one of the most historic and versatile ultra-flat movements in horology. Its design inspired multiple generations of dress watches, and its precision engineering is admired by collectors and watchmakers alike. It continues to represent the pinnacle of traditional Swiss craftsmanship.

Looking to discover or purchase rare mechanical timepieces? Visit ExpertsWatches.com for curated collections and expert insights.