The best G-Shock for small wrists: five cases under 46mm, measured rather than guessed

Measure your wrist, then read the numbers

Take a tape measure round your wrist at the bone. Under about 6.5 inches (165 mm) is where most G-Shocks start to overhang, and under 6 inches (152 mm) only the cases on this page will sit flat. Everything below comes from Casio's published spec sheets, not from photographs, because photographs of watches are taken on large wrists at flattering angles.

Width matters less than you think

Three numbers decide whether a watch fits, and the one everyone quotes is the least important. Case width (the 42.9 mm figure) decides whether the case edges overhang. Case height or length — Casio's first figure, the 46.2 mm — decides whether the lugs dig in, and it is the number that actually stops a watch fitting. Case thickness decides whether it goes under a cuff and how much it catches on doorframes. A 42 mm watch 18 mm thick wears far bigger than a 45 mm watch 11 mm thick, which is exactly why the GA-2100 makes this list despite being wider than the square.

The five cases, measured

The GMA-S2100 wins every column that matters: narrowest, thinnest and lightest, at 41 grams. Casio markets it as its small case size, and it is the only G-Shock we rank that a 6-inch wrist can wear without the case edges hanging over. The square cases are a close second at 42.8 mm wide — they are noticeably taller and thicker, but the flat case sides mean they still sit well.

Why lug-to-lug is the number Casio hides

Casio does not publish a lug-to-lug figure the way a watch brand does, because a G-Shock's strap is integrated into the case. Its first dimension — 46.2 mm on the GMA-S2100, 48.9 mm on the square — is effectively that measurement, and it is where the case stops and the strap starts bending. On a narrow wrist this is the number that produces the "it fits but it rocks" feeling, and it is why the 46.2 mm GMA-S2100 sits flat where a 48.5 mm case does not quite.

What you give up at each size

Nothing structural. All five are 200 m, shock resistant, mineral crystal and resin banded, and the two Carbon Core Guard models add carbon reinforcement. What changes is the module:

• Solar and atomic time: only the GW-M5610U. It charges from any light and sets itself from the radio, and Casio states about ten months of running with no light at all.
• A full-dial backlight: the two squares and the DW-9052. The GMA-S2100 and GA-2100 have a Double LED that lights the hands and the small display, which is not the same thing.
• Sensors: none of them. Every compass-and-altimeter G-Shock is a big case. The nearest small sensor watch is the Pro Trek PRG-340 at 51.7 mm wide and 54 g — wider than everything here but the lightest triple-sensor Casio, and it is ranked in best Casio Pro Trek.

The G-Shocks to avoid on a small wrist

The decade pick

The same question for GPS watches, where the bigger case buys published battery hours rather than just presence, is answered in what size GPS watch to buy.

How to buy a G-Shock that fits

1. Measure, do not estimate. A tape measure round the wrist bone, in millimeters. Under 165 mm means stay on this page; under 152 mm means the GMA-S2100 or a square.

2. Read Casio's first dimension, not the second. The 46.2 mm / 48.5 mm figure is the effective lug-to-lug and it is what decides whether the case rocks.

3. Then read thickness. Under 12 mm (GMA-S2100, GA-2100) goes under any cuff. 13-15 mm (the squares, the DW-9052) is fine under most. Over 18 mm does not.

4. Accept no sensors. Every ABC G-Shock is a large case, without exception. If you need a compass on a small wrist, a Pro Trek or a Suunto Core is the answer, not a smaller G-Shock.

5. Consider a shorter strap. All five of these use standard G-Shock replacement straps, and a thinner aftermarket resin or nylon strap makes a real difference to how a square wears on a narrow wrist.