Seiko
Seiko movements
13 Seiko calibres on file (13 automatic), from Seiko’s own calibres, the ones inside Seiko-branded watches. Each row gives the Seiko figures with their source; open a calibre for its drawing, care figures and what replaces it.
Sources checked · How we source numbers
7S2x
Calibre faces and heights from the makers’ figures, all to one scale; the bar and each grid square are 10 mm. Not photos.
4R3x
All 4: 21,600 bph, rated −35 to +45 s/day.
- 4R38
7s3x
6R
All 3: 21,600 bph, rated −15 to +25 s/day.
- 6R55
8L3x
- 8L35
8R chronographs
- 8R48
4r5x
- 4R57
9R Spring Drive
- 9R65
Seiko figures in one table
Show the tables · 13 calibres, every figure with its source
7S2x
4R3x
| Calibre | Size | Height | Jewels | Beat rate | Reserve | Type |
|---|---|---|---|---|---|---|
| 4R34 | 27.4 mm3secondary source | — | 244 | 21,600 bph4 | 41 h4 | automatic |
| 4R35 | 27.4 mm5secondary source | 5.32 mm5secondary source | 232 Sources disagree: manufacturer 23 / secondary source 23, 245 | 21,600 bph2 | 41 h2 Sources disagree: manufacturer 41 h / secondary source 40, 41 h5 | automatic |
| 4R36 | 27.4 mm6secondary source | 5.32 mm6secondary source | 242 | 21,600 bph2 | 41 h2 Sources disagree: manufacturer 41 h / secondary source 40, 41 h6 | automatic |
| 4R38 | — | — | — | 21,600 bph7 | 41 h7 | automatic |
7s3x
6R
| Calibre | Size | Height | Jewels | Beat rate | Reserve | Type |
|---|---|---|---|---|---|---|
| 6R15 | 27.4 mm10secondary source | 5.32 mm10secondary source Sources disagree: secondary source 5.32 mm / secondary source 5.25 mm11 | 2312 Sources disagree: manufacturer 23 / secondary source 23/2411 | 21,600 bph12 | 50 h13 | automatic |
| 6R35 | 27.4 mm14secondary source | 5.25 mm14secondary source | 2415 | 21,600 bph15 | 70 h15 | automatic |
| 6R55 | — | — | 2416 | 21,600 bph16 | 72 h16 | automatic |
8L3x
8R chronographs
4r5x
9R Spring Drive
A dash means Seiko does not publish the figure or it is not in the documents we read; each calibre page says which.
Seiko movement questions
Which Seiko movement is the thinnest?
Which Seiko movements beat at 28,800 bph?
8L35, 8R48 beat at 28,800 bph (4 Hz); 4R34, 4R35, 4R36, 4R38, 4R57, 6R15, 6R35, 6R55, 7S26, 7S36 at 21,600 bph (3 Hz).
Which Seiko movement runs longest on a full wind?
6R55, at 72 h as Seiko rates it; 9R65 72 h, 6R35 70 h follow.
More movements
- 6R35 vs 6R55Side-by-side comparison with drawings to scale
- 7S26 vs 4R36Side-by-side comparison with drawings to scale
- 4R35 vs 6R35Side-by-side comparison with drawings to scale
- NH35 vs 4R35Side-by-side comparison with drawings to scale
- 4R36 vs NH36Side-by-side comparison with drawings to scale
- 7S26 vs NH35Side-by-side comparison with drawings to scale
- TMI movementsTime Module, the Seiko Instruments arm that sells NH and VK calibres to other watch brands
- Miyota movementsCitizen’s movement maker, selling to other watch brands
- ETA movementsthe Swatch Group’s movement maker
- Sellita movementsthe Swiss maker whose SW calibres share the ETA 28xx layout
- Citizen movementsCitizen’s own calibres, including Eco-Drive
- Casio modulesCasio’s modules, the number printed on the case back
- All movementsCatalogue by maker and type
Sources
Documents checked · Report a wrong number
- 1Esslinger & Co. — Genuine Seiko 3 Hand Automatic Watch Movement 7S26 (product page, movement marked 7S26C) · html · read
- 2Seiko Watch Corporation — Instructions: Seiko Automatic Diver's Watch Cal. 4R15/4R16/4R35/4R36/7S26/7S35/7S36 (English) · pdf · read
- 3CaliberCorner — Seiko Caliber 4R34 watch movement page · html · read
- 4Seiko Watch Corporation — Mechanical watch instructions, Cal. 4R34 (EN) · pdf · read
- 5Grail Watch — Grail Watch Reference: Seiko Cal. 4R35 · html · read
- 6Grail Watch — Grail Watch Reference: Seiko Cal. 4R36 · html · read
- 7Seiko Watch Corporation — Mechanical watch instructions, Cal. 4R35/4R36/4R37/4R38/4R71/4R72/4R39 (EN) · pdf · read
- 8CaliberCorner — Seiko Caliber 7S36 watch movement page · html · read
- 9Seiko Watch Corporation — Automatic Diver's Watch instructions, Cal. 4R15/4R16/4R35/4R36/7S26/7S35/7S36 (EN pages) · pdf · read
- 10Grail Watch — Grail Watch Wiki: Seiko 6R15 · html · read
- 11CaliberCorner — Seiko Caliber 6R15 watch movement page · html · read
- 12Seiko Watch Corporation — Automatic Diver's Watch instructions, Cal. 6R15 (EN pages) · pdf · read
- 13Seiko Watch Corporation — Automatic Watch instructions, Cal. 6R15 (EN pages) · pdf · read
- 14CaliberCorner — Seiko Caliber 6R35 watch movement page · html · read
- 15Seiko Watch Corporation — Diver's watch for air diving instructions, Cal. 6R35 (EN) · pdf · read
- 16Seiko Watch Corporation — Mechanical watch instructions, Cal. 6R55/6R5J (EN) · pdf · read
- 17Seiko Watch Corporation — Mechanical watch instructions, Cal. 8L35 (EN) · pdf · read
- 18Grail Watch — Grail Watch Reference: Seiko 8R48 · html · read
- 19Seiko Watch Corporation — Mechanical chronograph instructions, Cal. 8R46/8R48 (EN) · pdf · read
- 20Seiko Watch Corporation — Instructions: SEIKO Automatic Watch Cal. 4R57 (English/multilingual booklet) · pdf · read
- 21Grand Seiko (Seiko Watch Corporation) — Caliber 9R65 product page (specifications) · html · read