The 4R Caliber

The 4R Caliber is an independent, unofficial reference and collection-tracking app for Seiko watch enthusiasts. It is not affiliated with, endorsed by, or sponsored by Seiko Corporation. Browse the entire current global lineup — every collection, every region-exclusive release, every dial variation — searchable by model number. Explore a decade of past models in the archive, with a fun fact about each watch's caliber and history. FOR COLLECTORS • Mark watches as Owned or add them to your Wishlist • Track price paid vs. retail price, with running totals across your collection • Record condition, purchase location, and serial number for each watch you own • Add your own photo of your actual watch, not just the catalog shot • Export your whole collection as a PDF — ready for insurance records FOR RESEARCH • Compare any two watches side-by-side, spec for spec • See when a caliber was first introduced, so you know what's new and what's a Seiko workhorse • Get a rough fit hint based on your wrist size • One-tap search to shop for any watch across the web