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Casio watch · G-Shock · analog-digital module

Casio G-Shock GA-2100 (CasiOak)

The Casio GA-2100 measures 45.4 mm wide, 48.5 mm long (case length L, not lug to lug), and 11.8 mm thick, with 16 mm lugs. It fits wrists from ~17 cm (flat-fit estimate).

Sources checked · How we source numbers
Width (W)
45.4 mm3
Case length (L)
48.5 mm3
not lug to lug
Thickness
11.8 mm3
Lug width
16 mm4
Casio GA-2100: size drawingCasio GA-2100, cushion case, top and side view to scale: case width 45.4 mm, case length (Casio L) 48.5 mm, lug width 16 mm, thickness 11.8 mm. Bezel, dial and crown size are schematic.lug width 16width 45.4case length (Casio L) 48.5TOPthickness 11.8SIDE
Casio GA-2100, top and side, to scaleDrawing from data, not a photo · mm

Module 5611 twins

Casio's manual list puts 90 model codes on this module: same functions, same manual, often the same battery.

Codes of the Casio GA-2100 family[6]GA-2100, GA-2100AB25, GA-2100AH, GA-2100BCE, GA-2100BM, GA-2100BP, GA-2100BWP, GA-2100CA, GA-2100CC, GA-2100CM, GA-2100FF, GA-2100FL, GA-2100FR, GA-2100FT, GA-2100GB, GA-2100HC, GA-2100HD, GA-2100HDS, GA-2100HT, GA-2100HUF, GA-2100K, GA-2100LXB, GA-2100NN, GA-2100P, GA-2100PT, GA-2100PTS, GA-2100RC, GA-2100RGB, GA-2100RL, GA-2100RRB, GA-2100RW, GA-2100SB, GA-2100SKE, GA-2100SR, GA-2100SRS, GA-2100SU, GA-2100TH, GA-2100THB, GA-2100THS, GA-2100TL, GA-2100TLS, GA-2100VB, GA-2100WD, GA-2100WS

46 more codes on the same module

GA-2110ET, GA-2110MK, GA-2110SC, GA-2110SU, GA-2140RE, GAE-2100GC, GAE-2100RC, GAE-2100WE, GM-2100, GM-2100B, GM-2100BB, GM-2100BM, GM-2100BRW, GM-2100C, GM-2100CB, GM-2100CH, GM-2100CL, GM-2100G, GM-2100LXB, GM-2100M, GM-2100MF, GM-2100MG, GM-2100N, GM-2100RI21, GM-2100RW, GM-2100SS, GM-2100TTTR, GM-2100WS, GM-2100YM, GM-2100YMG, GM-2100YRA, GM-2110D, GMA-S2100, GMA-S2100BA, GMA-S2100BS, GMA-S2100GA, GMA-S2100MD, GMA-S2100NC, GMA-S2100P, GMA-S2100PR, GMA-S2100RB, GMA-S2100SK, GMA-S2100WS, GMA-S2100WT, LOV-22B-G1, LOV-22B-G2

Casio module 5611: functions, battery and manual

Casio GA-2100 strap size

Lug width 16 mm4seller listing: a 16 mm strap with 16 mm spring bars fits between the lugs. 1 other model takes 16 mm.

Attachment: not published in our sources.

Find your strap length in the watch strap size tool, with the Casio GA-2100 filled in.

16 mm strap: strap diagramTwo-piece strap laid flat (16 mm strap). Lug width 16 mm. Short piece — (unknown), long piece — (unknown). Buckle, keepers and holes are schematic.short —long —lug 16lug 16strap length —16 mm strap
16 mm at the lugs; lengths depend on your wristDrawing from data, not a photo · mm

On your wrist

The verdict compares the case length (L) with the flat top of your wrist. Balanced from ~17 cm, past the edges below ~15.5 cm.

= 6.7 in

Balanced on a 17 cm wrist: the 48.5 mm case length (L) covers 88% of an estimated 54.8 mm flat top.

Casio publishes no lug-to-lug for this model, so the verdict uses its case length (L). The strap or bracelet joins inside that length, which makes this a cautious estimate.

Casio cuts the band for wrists of 14.5–21.5 cm: your wrist is inside that range.

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.

Casio GA-2100: wrist fitCasio GA-2100 on a wrist, top view to scale. case length (Casio L) 48.5 mm. Wrist 170 mm, estimated flat width 54.8 mm (circumference / 3.1). Ratio 0.88: balanced.wrist, flat topwrist flat ≈ 54.8case length (Casio L) 48.5Balanced · 48.5 / 54.8 = 0.88estimate: wrist 170 / 3.1 = 54.8 flatcompactbalancededgeoverhang0.750.891
Casio GA-2100 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 Casio GA-2100 at 1:1, next to a millimetre ruler.

1:1 · not calibrated: sizes are approximate
Casio GA-2100: size drawingCasio GA-2100, cushion case, top and side view to scale: case width 45.4 mm, case length (Casio L) 48.5 mm, lug width 16 mm, thickness 11.8 mm. Bezel, dial and crown size are schematic.lug width 16width 45.4case length (Casio L) 48.5TOPthickness 11.8SIDE
Drawing from data, not a photo · mm
01020304050

Casio GA-2100 specifications

Case width (W)
45.4 mm3
Lug to lug
not published by Casio; see case length (L)
Case length (L)
48.5 mm3Casio's L of L × W × H, measured differently from lug to lug; we never swap one for the other.
Thickness (H)
11.8 mm3
Lug width
16 mm4seller listing16 mm watches
Weight
51 g3
Crystal
Mineral Glass3
2 sources disagree; show every value
  • manufacturer Mineral Glass3
  • secondary source Mineral1
Water resistance
200 m (wr 20 bar)3
2 sources disagree; show every value
  • manufacturer 200 m (wr 20 bar)3
  • secondary source 200-Meter Water Resistance, Shock Resistant1
Module
Casio module 56116
2 sources disagree; show every value
  • manufacturer Casio module 56116
  • manufacturer Casio module 57116
 · analog-digital moduleCasio module 5611 specs
Battery
Accuracy
±15 s/month3
Years made
20193
Case code
not used by Casio: the module number (module 5611) identifies the watch
Band fits
145–215 mm wrist3

Module: Casio module 5611

The Casio GA-2100 runs on the Casio module 5611, an analog-digital module.

Power source
battery2
Battery life
3 years2
Accuracy
±15 s/month2
Light
double LED2

Battery

Same size as the Casio GA-2100

The models nearest to the Casio GA-2100 in case width and case length (L), drawn over it to scale; below, every model within 1 mm of its 48.5 mm.

Size comparison: Casio GA-2100, Casio AE-1000W, Casio GBD-200, Casio AQW-101Top-view outlines to scale on one centre. A Casio GA-2100: W 45.4, L 48.5, lug 16, T 11.8. B Casio AE-1000W: W 45, L 48.2, lug —, T 13.8 (vs A: W −0.4 L −0.3 T +2). C Casio GBD-200: W 45.9, L 48.4, lug —, T 15 (vs A: W +0.5 L −0.1 T +3.2). D Casio AQW-101: Ø 46, L 49.1, lug —, T 14.9 (vs A: W +0.6 L +0.6 T +3.1).B W 45A W 45.4C W 45.9D Ø 46B L 48.2C L 48.4A L 48.5D L 49.1A Casio GA-2100W 45.4 · L 48.5 · lug 16 · T 11.8B Casio AE-1000WW 45 · L 48.2 · lug — · T 13.8vs A: W −0.4 L −0.3 T +2C Casio GBD-200W 45.9 · L 48.4 · lug — · T 15vs A: W +0.5 L −0.1 T +3.2D Casio AQW-101Ø 46 · L 49.1 · lug — · T 14.9vs A: W +0.6 L +0.6 T +3.1
A Casio GA-2100 and the 3 nearest in size, on one centre, to scaleDrawing from data, not a photo · mm

Nearest in size

  1. ACasio GA-2100this watch
  2. BCasio AE-1000WW −0.4 · L −0.3 · T +2 mm
  3. CCasio GBD-200W +0.5 · L −0.1 · T +3.2 mm
  4. DCasio AQW-101W +0.6 · L +0.6 · T +3.1 mm

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

Parts documented for the Casio GA-2100

6 claims for named aftermarket parts are in the catalogue. Each claim is tied to this exact model and its seller’s source.

Casio GA-2100 questions

Where is the manual for the Casio GA-2100?

The Casio GA-2100 runs Casio module 5611, and Casio publishes the operation guide for that module as a PDF: Casio operation guide 5611. The module number is stamped on the case back. All of the module’s models and its battery are on its page.

What strap size does the Casio GA-2100 take?

The Casio GA-2100 measures 16 mm between the lugs, so it takes a 16 mm strap with 16 mm spring bars. 1 other model in our base share that width.

Find the strap length for your wrist and the Casio GA-2100 in the watch strap size tool.

How big is the Casio GA-2100?

The Casio GA-2100 measures 45.4 mm wide, 48.5 mm long (Casio's L, not lug to lug), 11.8 mm thick, 51 g.

Will the Casio GA-2100 fit a 7-inch wrist?

Balanced: the Casio GA-2100's 48.5 mm case length (L) takes 85% of the ~57.4 mm flat top of a 7-inch (17.8 cm) wrist. By the same estimate (circumference ÷ 3.1) it sits balanced from about 17 cm and overhangs the flat top on wrists under about 15.5 cm.

What battery does the Casio GA-2100 take?

The Casio GA-2100 takes 2 × SR726SW, rated about 3 years.

What module is in the Casio GA-2100?

The Casio GA-2100 runs on the Casio module 5611, an analog-digital module. Casio's manual list puts 90 model codes on this module, 44 of them GA-2100 codes.

More Casio watches

Sources

Documents checked · Report a wrong number

  1. 1G-Central (G-Shock fan database) — G-SHOCK GA-2100 specs · html · read
  2. 2Casio Computer Co., Ltd. — Operation Guide 5611 (qw5611_EN.pdf) · pdf · read
  3. 3Casio America — GA2100-1A1 | Monochrome Black Analog-Digital Watch (product page) · html · read
  4. 4NY Watch Store — Casioak GA2100-1A1 G-Shock Replacement Band Bezel · html · read
  5. 5Sakura Watches — Casio Watch Strap Replacement Band 10597558 for GA-2100 · html · read
  6. 6Casio Computer Co., Ltd. — Watch manual search JSON (US locale), manual_search.support.json · json · read