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Seiko watch · 5 Sports · automatic

Seiko SRPE65

The Seiko SRPE65 measures 40 mm across, 44.6 mm lug to lug, and 11.5 mm thick, with 20 mm lugs. It fits wrists from ~16 cm (flat-fit estimate).

Sources checked · How we source numbers
Case
40 mm1
Lug to lug
44.6 mm1
Thickness
11.5 mm1
Lug width
20 mm1
Seiko SRPE65: size drawingSeiko SRPE65, round case, top and side view to scale: case diameter 40 mm, lug to lug 44.6 mm, lug width 20 mm, thickness 11.5 mm. Bezel, dial and crown size are schematic.lug width 20Ø 40lug to lug 44.6TOPthickness 11.5SIDE
Seiko SRPE65, top and side, to scaleDrawing from data, not a photo · mm

Seiko SRPE65 specifications

Case diameter
40 mm1
Lug to lug
44.6 mm1
Thickness
11.5 mm1
Lug width
20 mm120 mm watches
Weight
75 g1
Crystal
Hardlex1
Water resistance
10 bar (100 m)1
Movement
Seiko 4R361 · automaticSeiko 4R36 specs
Battery
none: the Seiko 4R36 is automatic
Years made
start not published
Case code
not in our data yet
Line
5 Sports1

On your wrist

The verdict compares the lug to lug with the flat top of your wrist. Balanced from ~16 cm, past the edges below ~14 cm.

= 6.7 in

Balanced on a 17 cm wrist: the 44.6 mm lug to lug covers 81% of an estimated 54.8 mm flat top.

Flat top = circumference ÷ 3.1, a community convention, not a measurement of your arm. Compact ≤ 0.75 of the flat top, balanced ≤ 0.89, at the edge ≤ 1. Compare more watches in the watch size calculator.

Seiko SRPE65: wrist fitSeiko SRPE65 on a wrist, top view to scale. lug to lug 44.6 mm. Wrist 170 mm, estimated flat width 54.8 mm (circumference / 3.1). Ratio 0.81: balanced.wrist, flat topwrist flat ≈ 54.8lug to lug 44.6Balanced · 44.6 / 54.8 = 0.81estimate: wrist 170 / 3.1 = 54.8 flatcompactbalancededgeoverhang0.750.891
Seiko SRPE65 on a 17 cm wristDrawing from data, not a photo · mm

Actual size on your screen

Calibrate once with a bank card and the drawing shows the Seiko SRPE65 at 1:1, next to a millimetre ruler.

1:1 · not calibrated: sizes are approximate
Seiko SRPE65: size drawingSeiko SRPE65, round case, top and side view to scale: case diameter 40 mm, lug to lug 44.6 mm, lug width 20 mm, thickness 11.5 mm. Bezel, dial and crown size are schematic.lug width 20Ø 40lug to lug 44.6TOPthickness 11.5SIDE
Drawing from data, not a photo · mm
01020304050

Seiko SRPE65 strap size

Lug width 20 mm1: a 20 mm strap with 20 mm spring bars fits between the lugs. 62 other models take 20 mm.

Attachment: not published in our sources.

Find your strap length in the watch strap size tool, with the Seiko SRPE65 filled in.

On a bracelet? How to remove watch links to size it to your wrist.

20 mm strap: strap diagramTwo-piece strap laid flat (20 mm strap). Lug width 20 mm. Short piece — (unknown), long piece — (unknown). Buckle, keepers and holes are schematic.short —long —lug 20lug 20strap length —20 mm strap
20 mm at the lugs; lengths depend on your wristDrawing from data, not a photo · mm

Movement: Seiko 4R36

The Seiko SRPE65 runs on the Seiko 4R36, an automatic movement. 47 other models in our base use it.

Beat rate
21,600 bph2
Power reserve
41 h2
2 sources disagree; show every value
  • manufacturer 41 h2
  • secondary source 40, 41 h4
Jewels
242
Accuracy
−35 to +45 s/day3
Hacking seconds
Yes2
Hand winding
Yes2

Battery

none: the Seiko 4R36 is automatic

A mechanical watch has no cell to replace; it needs a service instead.

Same size as the Seiko SRPE65

The models nearest to the Seiko SRPE65 in case width and lug to lug, drawn over it to scale; below, every model within 1 mm of its 44.6 mm.

Size comparison: Seiko SRPE65, Dan Henry 1962 Racing Chronograph Black, Seiko SRPE41, Seiko SRPE43Top-view outlines to scale on one centre. A Seiko SRPE65: Ø 40, L2L 44.6, lug 20, T 11.5. B Dan Henry 1962 Racing Chronograph Black: Ø 39, L2L 45.9, lug 20, T 13.5 (vs A: Ø −1 L2L +1.3 lug 0 T +2). C Seiko SRPE41: Ø 38.5, L2L 45.4, lug 20, T 11.8 (vs A: Ø −1.5 L2L +0.8 lug 0 T +0.3). D Seiko SRPE43: Ø 38.5, L2L 45.4, lug 20, T 11.8 (vs A: Ø −1.5 L2L +0.8 lug 0 T +0.3).C Ø 38.5D Ø 38.5B Ø 39A Ø 40A L2L 44.6C L2L 45.4D L2L 45.4B L2L 45.9A Seiko SRPE65Ø 40 · L2L 44.6 · lug 20 · T 11.5B Dan Henry 1962 Racing Chronograph BlackØ 39 · L2L 45.9 · lug 20 · T 13.5vs A: Ø −1 L2L +1.3 lug 0 T +2C Seiko SRPE41Ø 38.5 · L2L 45.4 · lug 20 · T 11.8vs A: Ø −1.5 L2L +0.8 lug 0 T +0.3D Seiko SRPE43Ø 38.5 · L2L 45.4 · lug 20 · T 11.8vs A: Ø −1.5 L2L +0.8 lug 0 T +0.3
A Seiko SRPE65 and the 3 nearest in size, on one centre, to scaleDrawing from data, not a photo · mm

Nearest in size

  1. ASeiko SRPE65this watch
  2. BDan Henry 1962 Racing Chronograph BlackW −1 · L2L +1.3 · T +2 mm
  3. CSeiko SRPE41W −1.5 · L2L +0.8 · T +0.3 mm
  4. DSeiko SRPE43W −1.5 · L2L +0.8 · T +0.3 mm

Differences against A in mm: W case width, L2L lug to lug, T thickness. Nearest by width and length together, from the published sizes.

Same published case dimensions (7)Seiko SRPE51, Seiko SRPE53, Seiko SRPE55, Seiko SRPE57, Seiko SRPE61, Seiko SRPE67, Seiko SRPE69

Same movement: Seiko 4R36

All 48 models on the Seiko 4R36

Seiko SRPE65 questions

How big is the Seiko SRPE65?

The Seiko SRPE65 measures 40 mm across, 44.6 mm lug to lug, 11.5 mm thick, 75 g.

Will the Seiko SRPE65 fit a 6.5-inch wrist?

Balanced: the Seiko SRPE65's 44.6 mm lug to lug takes 84% of the ~53.3 mm flat top of a 6.5-inch (16.5 cm) wrist. By the same estimate (circumference ÷ 3.1) it sits balanced from about 16 cm and overhangs the flat top on wrists under about 14 cm.

Does the Seiko SRPE65 need a battery?

No. The Seiko SRPE65 has no cell to replace: a wound mainspring drives its automatic Seiko 4R36.

What movement is in the Seiko SRPE65?

The Seiko SRPE65 runs on the Seiko 4R36, an automatic movement.

What strap size does the Seiko SRPE65 take?

The Seiko SRPE65 measures 20 mm between the lugs, so it takes a 20 mm strap with 20 mm spring bars. 62 other models in our base share that width.

Find the strap length for your wrist and the Seiko SRPE65 in the watch strap size tool.

More Seiko watches

Sources

Documents checked · Report a wrong number

  1. 1Seiko Watch Corporation — SRPE65 product page (5 Sports), seikowatches.com global-en · html · read
  2. 2Seiko Watch Corporation — Instructions: Seiko Automatic Diver's Watch Cal. 4R15/4R16/4R35/4R36/7S26/7S35/7S36 (English) · pdf · read
  3. 3Seiko Watch Corporation — Instructions: Diver's Watch for Air Diving, Cal. 4R35 / 4R36 (English) · pdf · read
  4. 4Grail Watch — Grail Watch Reference: Seiko Cal. 4R36 · html · read
  5. 5Seiko Watch Corporation — Instructions: Mechanical watch, Cal. 4R35 / 4R36 / 4R37 / 4R38 / 4R71 / 4R72 / 4R39 (English) · pdf · read