It’s the quartz oscillator inside your watch. Most of the Casio watches gain seconds. Some also lose seconds. If you look in your owner’s manual, it will give you the specs which can be plus or minus 20 or 30 seconds a month. I hate it when a watch loses time too. I would return the watch if I were you and get one that gains seconds.

 

Isn't the spec of most g's +-15s / month?

 

All of my 12 Gshocks gain seconds but according to Casio's manual, they can lose seconds as well

 

Thanks for all the replies. I have just looked at the manual. And it indeed says that the accuracy is +-30 seconds per month. I was initially surprised because I thought, mistakenly, that quartz watches could not run slow.

It is an inexpensive Baby-G. But I like the look of it.

 

Here is the pic of it. The font they use for 3, 9, 12 remind me of the old Explorer. The dial looks like it has a sunburst effect as well.

 

NIST recommends manufacturers to have no more than +/- 0.5s error every other day. This matches typical +/- 15s / month error for G-Shocks. 30s/month = ~ 1s/day.

So, 4s error in 4 days looks about right for a Baby G.

If it was more than that, I'll return or exchange it .

 

My Casio Royale loses 0.13 seconds per day. All my other Casios gain.

But, my Armitron Griffy (LED digital) loses 0.36 seconds per day.

Timex MK1 (quartz analog) loses 0.11 s/d.

I'm two weeks into tracking my Hamilton PSR, and it's dead-nuts at +/- 0... synced it with the atomic clock when I got it.

 

Check the module, you might have a trimmer for the crystal. It's tricky and delicate to adjust it but that can adjust the rate.
If you don't have a trimmer, your other option is to replace the quartz crystal. There's a bit of a luck of the draw with these watches due to the particularities of each quartz crystal. All should be within spec, but some will be more accurate than others.

However at -7.5spm, you're well within spec.

 

wow !
a baby G
an analog baby G
loosing 1 second every 96 hours
and there is a guy out there noticed that, and cares enough to log into a forum to ask
wow !

 

A lot of quartz watches gain over time so maybe in a year or so it will be spot on?
If you had a Rolex or something costing thousands and posted the same thing on their forums people would most likely be saying wow that's really good lol

 

Trimmer condenser.

 

My G2900 is about as slow as OP's. I'm not using it to time rocket launches, so a few seconds is fine

 

It is what it is. Most Casio watches gain seconds each month. Very few lose seconds. I would stop wearing the watch and wear something else that gains seconds or get another different model Casio if that happened to me.