Casio G-Shock GA-100-1A1
G-Shock · Casio

Casio G-Shock GA-100-1A1

Ref. GA-100-1A1 · Amazon ASIN B003WPUU0U
Digital quartz (analog-digital)Mineral crystal200 m51.2 × 55 mm

The big analog-digital G-Shock: 51.2 mm resin case, 200 m water resistance, speed indicator, world time, 1/1000-second stopwatch. Mineral crystal, LED light.

Case diameter51.2 mm
Lug-to-lug55 mm
Thickness16.9 mm
Warranty1 years
Fits wrist from19.8 cm (7.8″)
Amazon price · new
$83.60
List price $120.00
Value Score
83 of 100
Rank in type
3 of 6 G-Shock watches
Spec points
49
vs. type median
-10% ($93)
Amazon sales rank
#37 wrist watches
View GA-100-1A1 on Amazon

In stock · sold by Amazon.com. Price as of November 3, 2026, 18:15 UTC.

Wrist fit

Will the Casio G-Shock GA-100-1A1 fit your wrist?

Enter your wrist circumference. The drawing scales the case (51.2 mm across, 55 mm lug-to-lug) against the flat top of a wrist that size, using the 3.6× lug-to-lug rule from our fit guide. Needs JavaScript; the rule itself is on the fit guide.

Specifications

What you get

Published manufacturer specifications. Fields we could not verify are left out rather than guessed.

ReferenceGA-100-1A1
MovementDigital quartz (analog-digital)
CrystalMineral
Water resistance200 m
Case diameter51.2 mm
Lug-to-lug55 mm
Thickness16.9 mm
Strap / braceletResin
LumeYes
Calendardate, day
Warranty1 years
Fits wrist from19.8 cm (7.8″)
Value Score

How the 49 spec points add up

Value Score = 100 × √(spec points per dollar ÷ the best ratio among G-Shock watches in stock on Amazon today). Full methodology.

Digital quartz+14
Mineral crystal+8
200 m water resistance+17
Resin strap+3
Luminous hands and markers+4
Date+2
Day+1
Spec points49
Head to head

Comparisons with the Casio G-Shock GA-100-1A1

FAQ

Questions about the Casio G-Shock GA-100-1A1

How much does the Casio G-Shock GA-100-1A1 cost on Amazon?
As of November 3, 2026, 18:15 UTC, the Casio G-Shock GA-100-1A1 (GA-100-1A1) is listed new on Amazon at $83.60, sold by Amazon.com. That is 10% below the median of the 8 G-Shock watches we track with a live price ($93). Prices change; the price shown on Amazon at checkout applies.
What is the Value Score of the Casio G-Shock GA-100-1A1?
Value Score 83. It earns 49 spec points (Digital quartz (analog-digital), mineral crystal, 200 m water resistance) and today's price of $83.60 gives 58.6 points per $100. The score is 100 times the square root of that ratio divided by the best ratio among G-Shock watches in stock on Amazon today. The formula is published on our methodology page.
What wrist size fits the Casio G-Shock GA-100-1A1?
The case is 51.2 mm across. We do not have a verified lug-to-lug figure for this reference, so we do not publish a wrist-fit estimate.
Read next

Guides that apply to this watch