Setting a G-Shock is the same four-button routine on almost every model: hold the top-left button until the display flashes, step through the fields with the bottom-left button, change values with the right-hand buttons, and press top-left again to save. The differences are which field comes first and whether the watch can just sync itself from a phone or a radio signal. This guide covers the general procedure, then the specifics for the GA100, GD100, GBD800, GBX100 and Rangeman GW9400.
The buttons
On every G-Shock the four buttons are named the same way: A is top-left (Adjust), B top-right, C bottom-left (Mode), D bottom-right. Your watch's module number is engraved on the case back; Casio's manual for that module is the final word.
The general procedure (digital and analog-digital)
- In timekeeping mode, hold A (top-left) for about two seconds until the city code or the seconds start flashing.
- Press C (bottom-left) to move through the fields: city code → DST → 12/24-hour → seconds → hour → minutes → year → month → day.
- Press D (bottom-right) to increase a value and B (top-right) to decrease. Hold either to scroll fast. With seconds flashing, press D to reset them to 00.
- Press A to save and exit.
Set the city code first (for the U.S., NYC, CHI, DEN, LAX and so on): on most models the time zone comes from the city, and changing the hour instead will break the world-time and alarm functions.
Analog-digital models: aligning the hands
On the GA100, GA110 and GA010 the hands follow the digital time automatically. If they are off after a knock or a battery change, do a hand home-position correction: hold A for about five seconds until H.SET appears, use D and B to move the hands until they point at 12:00, then press A. The hands return to the correct time on their own.
Models that set themselves
The Rangeman GW9400 is Multi-Band 6: it receives the atomic time signal overnight, so you only set the city code and DST and let it sync (put it near a window; press D in timekeeping to trigger a manual receive). The GBX100 and GBD800 sync from the Casio Watches app over Bluetooth: pair once, and time, city and DST follow your phone. Their manual procedure is the same hold-A routine if you would rather not use the app.
Daylight saving time
Most G-Shocks have a DST field right after the city code: OFF, ON or AUTO. Set AUTO if the watch has it. If your watch is an hour off in spring or fall, this field is why.
Model quick reference
| Model | Module | Type | Sync | Guide |
|---|---|---|---|---|
| GA100 / GA100MB | 5081 | Analog-digital | Manual | GA100 guide |
| GD100 | 3263 | Digital | Manual | GD100 guide |
| GBD800 | 3464 | Digital | Bluetooth app | GBD800 guide |
| GBX100 | 3482 | Digital MIP | Bluetooth app | GBX100 guide |
| Rangeman GW9400 | 3410 | Digital | Multi-Band 6 radio | Rangeman guide |
Frequently asked questions
How do I set the time on a G-Shock?
Hold the top-left button until the display flashes, press bottom-left to move between fields, use the right-hand buttons to change values, press top-left to save.
Why is my G-Shock an hour off?
The DST setting or the city code. Set the city for your zone and DST to AUTO.
How do I fix the hands on an analog-digital G-Shock?
Hold A about five seconds until H.SET shows, move the hands to 12:00 with D and B, press A.
Do G-Shocks set themselves?
Multi-Band 6 models like the Rangeman sync to the atomic signal; Bluetooth models like the GBX100 and GBD800 sync from the Casio app.
Where is the module number?
Engraved on the case back, usually a four-digit number.
The bottom line
Hold A, step with C, change with D and B, save with A. Set the city code and DST first. The GA100 and GD100 are the manual-set classics; the Rangeman sets itself.
Related reading
How to set a G-Shock GA100
Best G-Shock for EDC
Are G-Shock watches good (and waterproof)?
