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How to Change a G-Shock Between 12-Hour and 24-Hour Military Time

I love my Casio G-Shock watch, but it took me a while to figure out how to change it to military time.

Instructions to Change a Casio G-Shock Watch Between 12-Hour and 24-Hour Military Time

  1. Locate each of the 5 watch buttons. In the clock face position, they are located at 2 o’clock, 4 o’clock, 6 o’clock, 8 o’clock, and 10 o’clock.
  2. Push the button at 10 o'clock. This makes the second digits blink.
  3. Then push the button at 6 o'clock. Presto! The hour digits change from civilian time to military time, or vice versa.
  4. Press the button at 10 o'clock again to stop the second digits from blinking. If it is earlier than 1:00 pm, you won't be able to tell the difference between the civilian and military format by looking at the digits. To know whether you are in military format, a "24" will be displayed.
An old Casio G-shock Watch.

An old Casio G-shock Watch.

How I Figured It Out

Somehow, my watch changed from a civilian 12-hour time format to a 24-hour military format. Since the watch was seldom used, I put up with the inconvenience. It was an inconvenience because the only military time I really knew was 16:00 (4 o’clock). I remember 16:00 from my very brief experience with the military. This time signaled the end of the workday (the most important time of the day). When the formatting on my watch changed, I had to base all of my time-telling from 16:00. It sort of worked but was becoming a pain.

So I went to the fount of all information—the internet—but I could not find the answer. Finally, I decided to dig out the easy-to-follow directions that came with the watch. I am sharing this wonderful piece of information with you just in case you've lost the instructions.

© 2010 Edward Kirk


Darlene on July 20, 2020:

Thank you!! I bought it as a gift for my boyfriend and he threw away the instructions, he gave me back the watch when he couldnt figure it out and said it didnt work!

George Drewett on June 02, 2020:

How do I set iPhone time

a random guy on May 28, 2020:

yea i did this and its stil not working.

Sweep on March 09, 2020:

Nice work. Thanks!

Michelle on February 24, 2020:

Thank you so much!

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Gary on November 09, 2019:

Dude I have dealing with problem for days I was ready to get a new one I can't believe I found you exact watch I have had it for years thanks man

TickTockMan on September 28, 2019:

Thanks so much for posting this—I lost my instructions, and was going crazy, trying all the combinations I could think of. It never occurred to me that the center "G" button was useful for anything other than lighting up the display at night.

Benjamin on September 15, 2019:


Me on May 10, 2019:

You must have had the good life to end the day at 1600!!

me on December 14, 2018:


margie on November 20, 2018:

thank you..

Thatguy55 on September 03, 2018:

Thanks a million. It didn't work on my dads 10-15 year old one, though.

ahmet on June 23, 2018:

Thank you soo much

Emily on April 16, 2018:

Thank you for your super helpful and clear instructions!

Michael jones on March 29, 2018:

Thank you

Eli_Pack on March 11, 2018:

Thank you SO much! Mom bought mine used also, and was driving us both crazy;happened when springing forward a hour lol. The instructions were very clear;after mom figured out the 6 button was the light lol

Thanks again

Jayy_Bruhh on January 28, 2018:

Thank u soo much!!

Neel on November 16, 2017:

It helped

Thimon on November 14, 2017:

It freaking work

Lerish on September 10, 2017:

Oh wow it was super easy...was bothered for a while with this. thanks for the solution.

emily on January 19, 2017:

got this new watch and i tried alot of things and it is still on the military time): what do i do

MC on November 07, 2016:

So helpful! This has been driving me crazy for years, as I could never figure out how to change it out of military time (not sure how it got that way in the first place). Of course, I never thought to push the light button, though I tried everything else a million times!

Columbus on August 03, 2016:

Thanks. So easy.

carlos on October 30, 2015:

Thanks i forgot about pressing the 6 button i had this watch for over a decade we been in 45 states 3 continents 11 countries on foot on 2,4,8 and 18 wheels days and nights in dirt crud mud fog blood snow in the water in the woods in the mountains and the desert ill keep it till it dies

Derick on August 23, 2015:

Thanks so much!... Now, my daughter can use the military time she always wanted since the day I bought her first G-Shock...

Ernie on April 14, 2015:

Thank you so much! This was too useful.

Bree on March 08, 2015:


Joel on October 26, 2014:

Thanks helped a lot, couldn't remember how to put it back to military time

qwwr on October 24, 2014:

thx did the reverse though :)

fk11 on June 21, 2014:

anybody know how to adjust time and date for GD-100 Gshock model? thanks

sherodh251 on June 16, 2014:

Adjust then the G

balanga on June 04, 2014:

TNX!!! I hate the 12-hour conditin, and you helped me getting rid of it.

Mixan on May 11, 2014:

Thank you very much for the helpful guide..Nice..!!

mh on February 27, 2014:

Thx you so much

Ec on January 21, 2014:

For newer g shocks i find that if you press adjust until my date starts blinking then press mode until 24 hr time show up then press start and magic it works. Or the 12 hr time to 24 hr time doesn't matter.

AJ on April 08, 2013:

You rock! Thanks...

Mickey on March 16, 2013:

The most simple thing to adjust and hardest thing to find info on. Thanks so much.

altan on February 14, 2013:

very thank you

Curtis on January 11, 2013:

Thanks. I am in the military and used your instructions, but in reverse. Very easy and helpful.

Erick on November 14, 2012:

Thanks C:

G-Shock man on November 12, 2012:

changed the battery and it switched the hour format. took less than 30 seconds to find this site and find out how to fix it. thanks a lot!

Lisa on July 21, 2012:

OMG, who would have guessed the light button?! I tried every combo and have been living with military time for about 3 years. Thanks a million!

dandan on June 18, 2012:


hollybush inn on June 14, 2012:

spot on cheers. it was doing me nut

MR.Marchai on June 06, 2012:

thanks hab

chaka on June 06, 2012:

it was really easy

give your g-shock now! on May 10, 2012:


John Tayao on April 13, 2012:

thanks!!!! it worked!

Casio watches on March 18, 2012:

Excellent blog so be sure to continue! That helped me a lot i just trying for a few months....

lucallen on March 15, 2012:

mine's been that way for a few months. i just quit trying... thanks for the help!

jmp on March 11, 2012:

thanks only took a sec. to change been trying for an hour or so. lol.

curtis on March 05, 2012:

been trying to figure that out for a few days.. thanks!

ivan on February 22, 2012:


Stef on February 21, 2012:

This works i was wondering how to change back my watch but tanx to this i finnally got it changed

CUATRUS on February 16, 2012:


logan on February 10, 2012:

Wow that worked thanks been trying to find out how to do it

Ric on February 06, 2012:


Bizzkid on January 14, 2012:

This was drivin me nuts thanks for the help. Tried everything, but the light button. You couldn't have made it any easyier. thanks again!

Sean on January 03, 2012:

None of the above worked for me, i have a GR-8900A-1

For this model you have to hold down the 10 o'clock

until the words start to flash, press the 8 o'clock, followed by the 4 o'clock.

baggedgmc on December 25, 2011:

Wow thanks for that trick buddy. . . P.s. bagged out trucks rule (

stev on December 25, 2011:

this helped so much, thank you

gazza on December 06, 2011:

thanks heaps!!!

hab on November 27, 2011:

if you have a new version of the g shock and you want to change it from 12hr mode to 24 hr mode just press the 4 o clock button and it fixes it

howie on November 26, 2011:

Cheers thank you

milton on November 18, 2011:

Thanx a lot I've been wanting to switch my G-shock into military time for a while and thanx to u and to google for they're "search" thingy I found this.. thanx again..

t on November 11, 2011:

I pushed every button in as many different ways possible....except the light button...thx!!!

cihs on October 21, 2011:

very helpfull :)

Moto on October 12, 2011:

Great help! works on 16 year old G-shock :)

chris on July 29, 2011:

thank ****** this is the first thing i find! awesome!

i love technology!

Edward Kirk (author) from Maryland on June 12, 2011:

I really do not want to give you this answer but I must. Some of the newer models of G-Shock watch require a different combination of buttons; refer to your manual for the exact procedure. If the manual is not available go to the Casio web site and follow the daisy chain to get a PDF for your exact watch manual. You will need the module number from the back of the watch.

David on June 10, 2011:

I have the exact same problem with my brand new g shock. I held down the 10 o'clock button until the seconds started blinking then held down the light button at 6 o'clock and nothing happened, the face of the watch just lit up. Any help?

Rick on March 20, 2011:

yes that was great, instead of the dumbasses that tell you to look at the manual........if I still had it twenty years later I would have morons........again thanx

Sasha on March 18, 2011:

god bless you, same story, same problem, thx a lot (by the way, my G-Shocks works since more than 13 years, amazing)

ray on February 25, 2011:

thanks this really helped...!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

maiky payano on February 15, 2011:

thanks a lot :] very helpful

Edward Kirk (author) from Maryland on January 22, 2011:

Do what I say. Push the 10 o'clock button then 6 o'clock (yes the light button) that was the secret to the whole thing.

madison on January 22, 2011:

hey i am having the same problem but the botton at six o clock is the light button, some clarification please.

just email me

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