Casio G-Shock GD100-1B
G-Shock · Casio

Casio G-Shock GD100-1B

Ref. GD100-1B · Amazon ASIN B003URSIKO
Digital quartzMineral crystal200 m51.2 × 55 mm

The big digital G-Shock: 51.2 mm resin case, 200 m water resistance, super-bright LED backlight, world time and a 1/100-second stopwatch.

Case diameter51.2 mm
Lug-to-lug55 mm
Thickness17.4 mm
Warranty1 years
Fits wrist from19.8 cm (7.8″)
Amazon price · new
$70.98
List price $110.00
Value Score
90 of 100
Rank in type
2 of 6 G-Shock watches
Spec points
49
vs. type median
-24% ($93)
Amazon sales rank
#35 wrist watches
View GD100-1B on Amazon

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

Wrist fit

Will the Casio G-Shock GD100-1B 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.

ReferenceGD100-1B
MovementDigital quartz
CrystalMineral
Water resistance200 m
Case diameter51.2 mm
Lug-to-lug55 mm
Thickness17.4 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
FAQ

Questions about the Casio G-Shock GD100-1B

How much does the Casio G-Shock GD100-1B cost on Amazon?
As of November 3, 2026, 18:15 UTC, the Casio G-Shock GD100-1B (GD100-1B) is listed new on Amazon at $70.98, sold by Amazon.com. That is 24% 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 GD100-1B?
Value Score 90. It earns 49 spec points (Digital quartz, mineral crystal, 200 m water resistance) and today's price of $70.98 gives 69.0 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 GD100-1B?
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.
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Guides that apply to this watch