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Casio watch · Casio G-Shock GA-100 · analog-digital module

Casio GA-100 battery (CR1220) and manual

The Casio GA-100 takes CR1220, rated about 2 years. The case is 51.2 mm wide, 55 mm long (case length L, not lug to lug), and 16.9 mm thick. Manual: Casio operation guide 5081 (PDF) ↗.

Sources checked · How we source numbers
Width (W)
51.2 mm1
Case length (L)
55 mm1
not lug to lug
Thickness
16.9 mm1
Lug width
not published by Casio
Casio GA-100: size drawingCasio GA-100, cushion case, top and side view to scale: case width 51.2 mm, case length (Casio L) 55 mm, lug width — (unknown), thickness 16.9 mm. Bezel, dial and crown size are schematic.lug width —width 51.2case length (Casio L) 55TOPthickness 16.9SIDE
Casio GA-100, top and side, to scaleDrawing from data, not a photo · mm

Module: Casio module 5081

The Casio GA-100 runs on the Casio module 5081, an analog-digital module.

Power source
battery2
Battery life
2 years2
Accuracy
±15 s/month2
Light
LED, auto light switch, selectable duration2

Battery

Module 5081 twins

Casio's manual list puts 53 model codes on this module: same functions, same manual, often the same battery.

Codes of the Casio GA-100 family[3]GA-100, GA-100A, GA-100B, GA-100BBN, GA-100BEG, GA-100BL, GA-100BNR, GA-100BP, GA-100BR, GA-100BT, GA-100BW, GA-100BY, GA-100C, GA-100CB, GA-100CF, GA-100CG, GA-100CM, GA-100CS, GA-100CX, GA-100CY, GA-100DA, GA-100DE, GA-100FL, GA-100GBX, GA-100GD, GA-100GGB, GA-100JK, GA-100L, GA-100LG, GA-100LT, GA-100LY, GA-100MB, GA-100MC, GA-100MF, GA-100MM, GA-100MMC, GA-100MRB, GA-100MT, GA-100MW, GA-100PC, GA-100RC, GA-100RGB, GA-100RS, GA-100SD, GA-100SHB, GA-100SKC, GA-100ST, GA-100TAL, GA-100TCB, GA-100TMN, GA-100TU, GA-100VLA, GA-100WD

Casio module 5081: functions, battery and manual

Casio GA-100 specifications

Case width (W)
51.2 mm1
Lug to lug
not published by Casio; see case length (L)
Case length (L)
55 mm1Casio's L of L × W × H, measured differently from lug to lug; we never swap one for the other.
Thickness (H)
16.9 mm1
Lug width
not published by Casio
Weight
70 g1
Crystal
Mineral Glass1
Water resistance
200 m1
Module
Casio module 50813 · analog-digital moduleCasio module 5081 specs
Battery
Accuracy
±15 s/month1
Years made
start not published
Case code
not used by Casio: the module number (module 5081) identifies the watch
Band fits
145–215 mm wrist1

On your wrist

The verdict compares the case length (L) with the flat top of your wrist. Balanced from ~19.5 cm, past the edges below ~17.5 cm.

= 6.7 in

Overhangs on a 17 cm wrist: the 55 mm case length (L) covers 100% of an estimated 54.8 mm flat top and runs 0.1 mm past it on each side.

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-100: wrist fitCasio GA-100 on a wrist, top view to scale. case length (Casio L) 55 mm. Wrist 170 mm, estimated flat width 54.8 mm (circumference / 3.1). Ratio 1.00: overhangs, 0.1 mm past the flat wrist on each side.wrist, flat topwrist flat ≈ 54.8case length (Casio L) 55Overhangs · 55 / 54.8 = 1.00 · overhang 0.1 per sideestimate: wrist 170 / 3.1 = 54.8 flatcompactbalancededgeoverhang0.750.891
Casio GA-100 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-100 at 1:1, next to a millimetre ruler.

1:1 · not calibrated: sizes are approximate
Casio GA-100: size drawingCasio GA-100, cushion case, top and side view to scale: case width 51.2 mm, case length (Casio L) 55 mm, lug width — (unknown), thickness 16.9 mm. Bezel, dial and crown size are schematic.lug width —width 51.2case length (Casio L) 55TOPthickness 16.9SIDE
Drawing from data, not a photo · mm
01020304050

Casio GA-100 strap size

Casio publishes no lug width for the Casio GA-100; its band is cut for wrists of 145–215 mm wrist1. Measure between the lugs with a caliper before buying a third-party strap.

Attachment: not published in our sources.

Find your strap length in the watch strap size tool, with the Casio GA-100 filled in.

Same size as the Casio GA-100

The models nearest to the Casio GA-100 in case width and case length (L), drawn over it to scale; below, every model within 1 mm of its 55 mm.

Size comparison: Casio GA-100, Casio GG-B100, Casio AE-1500, Casio PRG-270Top-view outlines to scale on one centre. A Casio GA-100: W 51.2, L 55, lug —, T 16.9. B Casio GG-B100: W 51.3, L 55.4, lug —, T 19.4 (vs A: W +0.1 L +0.4 T +2.5). C Casio AE-1500: W 51.2, L 54.4, lug —, T 15.7 (vs A: W 0 L −0.6 T −1.2). D Casio PRG-270: Ø 52.4, L 54.6, lug —, T 15 (vs A: W +1.2 L −0.4 T −1.9).A W 51.2C W 51.2B W 51.3D Ø 52.4C L 54.4D L 54.6A L 55B L 55.4A Casio GA-100W 51.2 · L 55 · lug — · T 16.9B Casio GG-B100W 51.3 · L 55.4 · lug — · T 19.4vs A: W +0.1 L +0.4 T +2.5C Casio AE-1500W 51.2 · L 54.4 · lug — · T 15.7vs A: W 0 L −0.6 T −1.2D Casio PRG-270Ø 52.4 · L 54.6 · lug — · T 15vs A: W +1.2 L −0.4 T −1.9
A Casio GA-100 and the 3 nearest in size, on one centre, to scaleDrawing from data, not a photo · mm

Nearest in size

  1. ACasio GA-100this watch
  2. BCasio GG-B100W +0.1 · L +0.4 · T +2.5 mm
  3. CCasio AE-1500W same · L −0.6 · T −1.2 mm
  4. DCasio PRG-270W +1.2 · L −0.4 · T −1.9 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.

Same published case dimensions (1)Casio GA-110

Casio GA-100 questions

What battery does the Casio GA-100 take?

The Casio GA-100 takes CR1220, rated about 2 years.

Where is the manual for the Casio GA-100?

The Casio GA-100 runs Casio module 5081, and Casio publishes the operation guide for that module as a PDF: Casio operation guide 5081. The module number is stamped on the case back. All of the module’s models and its battery are on its page.

How big is the Casio GA-100?

The Casio GA-100 measures 51.2 mm wide, 55 mm long (Casio's L, not lug to lug), 16.9 mm thick, 70 g.

Will the Casio GA-100 fit an 8-inch wrist?

Balanced: the Casio GA-100's 55 mm case length (L) takes 84% of the ~65.5 mm flat top of an 8-inch (20.3 cm) wrist. By the same estimate (circumference ÷ 3.1) it sits balanced from about 19.5 cm and overhangs the flat top on wrists under about 17.5 cm.

What module is in the Casio GA-100?

The Casio GA-100 runs on the Casio module 5081, an analog-digital module. Casio's manual list puts 53 model codes on this module, 53 of them GA-100 codes.

What strap size does the Casio GA-100 take?

Casio does not publish the lug width for the Casio GA-100. What Casio does publish is a band size: wrists of 14.5–21.5 cm, the wrist circumference its own band is cut for. That is a wrist range, not a strap width, so measure between the lugs with a caliper before you buy a third-party strap.

Find the strap length for your wrist and the Casio GA-100 in the watch strap size tool.

More Casio watches

Sources

Documents checked · Report a wrong number

  1. 1Casio America — GA100-1A1 | Digital Durable Men's Watch G-SHOCK | CASIO (product page) · html · read
  2. 2Casio Computer Co., Ltd. — Operation guide, module 5081 (qw5081_EN.pdf) · pdf · read
  3. 3Casio Computer Co., Ltd. — Watch manual search JSON (US locale), manual_search.support.json · json · read