As long as the date, the hour, the minute and the second of my PC are the same as a clock controlled by a Cesium atom and radio controlled clock, I am very satisfied. And ..... I have 12 on a Cesium atom-based radio-controlled clocks.

Seriously???

With just a little bit of work you can get within one second of accuracy using a scheduled polling of one of NIST's clocks. It requires modifying the PC registry, but it's easy to do. And it's absolutely free. Best of all, no new program to install or (eventually) pay for!

This may become of some importance if the backup battery for the motherboard's clock begins to fail. (A problem if the PC is unplugged for extended periods of time.)

Another useful app idea - an app that confirms what planet you're currently on. It should re-check every minute... just in case.
The PRO version would also confirm which universe you are in.

I have two telephone receivers connected to the same line. They are not extensions, just two plugged in to a double socket. (The reason, one is new and better and I keep the old one for emergency.) I get the time that is displayed from the phone company, remember both are on the same single line. This should give me the exact time from which to set my clocks. The displays on the two differ by about half a minute!!!! Sometimes they show a minute difference. Don't ask me why they differ or how it is possible, but it doesn't really matter to me anyway.

I don't know how i survived for so long without this. Can't download it now because my clock was a second slow and i'm late for work :)

To Mr. average PC user this is a total waste of TIME.

In some commercial applications time synchronization is important but that is usually handled by the servers such applications would pass through. Home users would rarely have need of such accurate timekeeping and as this is strictly for home use it kind of makes this a rather nicely executed piece of software rather surplus to requirements, but if it floats your boat ...

in the age of Tablets, smart phones, smart watches, watches, clocks on the wall and everywhere else, I could care less if my clock on my PC was right or NOT !

Damn, I need this . . .my computer was 0.37 seconds slow and i missed my bus

I'm surprised at all the comments from people who don't care if their clock is accurate. I always keep my watch as accurate as possible, and I like my computer that way, as well. Also, I am a ham radio operator, and for some types of digital communication that I do, milliseconds actually do count.

My BIOS time is not set right down to the milliseconds. Will this fix that?

As of windows XP ntp syncing system clock with internet based ntp time servers has been built in and on by default... if your PC loses time sync it is either not conected to the internet or has a hardware or malware fault. The hardware fault could be a failing battery that keeps the systems real time clock chip powered when disconected from a main power source so the RTC chips time keeping is becoming intermitent. Malware could radicaly change the system date to disrupt the windows update patching procedure and installation of software like malicious software removal tool etc. and if windows is denied network access for prolonged periods (months or years) its time will drift as the inbuilt Real Time Clock is just quartz crystal control and is NEVER calibrated for accuracy as it's expected to be nudged periodically by NTP time servers synced to atomic clock time standards.

If it randomly apears to shift its time by a fixed number of hours it could be one of the many subsystems experiencing resource depletion and soft crashing causing access to time zone data to become corrupted... more frequent reboot could resolve that or figuring out what software is eating resources... If you go to the date time applet and the displayed time zone name has changed it could be malware or data corruption.

Prior to WIndows XP... e.g. WIndows 95,98/SE,ME and 2000 did need third party tools to sync to atomic clocks over the internet... but nowadays it is simply not required or desired as it just increases the load on public ntp/sntp servers around the world for zero functional gain in any computer system less than 18 years old. Now if it could compensate for relatavistic variation depending upon GPS location and time of day and month and year and out esitmated velocitiy orbiting the imagined spiral galaxies core and the overall expansion velocity astrophycasists postulate we may be still expanding at from the hypothetical point of origin which is in an unknown directing... it would still be pointless since we have no fixed frame of reference for absolute time since we are in a micro-variable gravitational field and have no true concept of our abosolute velocity through space time to calculate the relatavistic perceived time dilation compared to a true stationary object not subjected to an external gravitational field.

In summary if your PC presistently goes noticably out of alignement with the current date and time or time zone then it is a fault and needs to be fixed not bodged around by a commercial tool that over burdens public time servers around the world to pretend to make an accurate enough system (when working as designed) more accurate than you can perceive or than computers can directly compare in most circumstances.

I'm retired. I need an app that tells me what day of the week it is!

You can check your device's time against an official reference source (corrected for any transmission delays) here: time.gov

There are useful links on the "about" page (including correctly setting up your computer's clock): time.gov/aboutB.html

For those of us that have computers that do not keep accurate time (requiring frequent large corrections -- I have an older model like this) it makes you wonder why the manufacturers seemingly can't include a decent temperature-compensated crystal oscillator (TCO) circuit as do better-yet-inexpensive bedside alarm clocks. I guess they expect the operating system (when running) to compute and apply periodic corrections, and occasionally synchronize with an online reference, in order to save a few pennies on motherboard hardware.

This software has its specialised use. If you have a use for it.
Like in Olympics speed skating where 1st vs 2nd is decided by a time difference of a few 1000th of a second.
For typical home user desk top PC, there is no meaningful use for clock accuracy to a millisecond.
It is tolerable for PC clock of a normal home user to be inaccurate by several seconds. Who cares?

Nice application, but I just asked my $1000 computer permission to install the millisecond synchronizer and dismayed. Still remains with blank eyes. Well...

Relatively precise (within .5 or less seconds) time is a requirement for certain types of digital radio communications such as FT4, FT8 and WSPR (and there are lots more); a couple of seconds slow or fast results in no communications. Sometimes syncing with Neutron produces inaccurate seconds. I do not know how this software compares to Meinberg NTP.

By the time you blink a 1/4 of a second has passed, no eye on earth can see a movement of a digit that fast and why you would want that much accuracy, when you see a digit on the screen and by the time you register that digit and by the time the optic nerve sends the impulse to the brain and by the time the brain interprets what digit it is, hundreds more digits have passed in front of the eye, therefore we can never record a precise time at all, we interpolate and round the time to a second or two, but we could never know the right time because it never stops to take a frozen record of it.

My Windows 7 has a time bug. My clock is 3 hours behind sometimes. I have to reset it all the time.

So long as I know what day of the week it is I'm fine.

The main use of this kind of software would be for a network server but the giveaway's terms of use clearly states
"3) Strictly non-commercial usage". That's not makes me happy :(

My system's clock could be off by an entire minute (60,000 milliseconds) and I wouldn't either (a) notice or (b) care.

My PC is already sychronised.
It does this automatically once a week.
Thats more than enough, far more than my digital watch gets!

I have the previous GAotD version (v4.3 from 2016) and use it from time-to-time. I tried some other programs but found this to be the best, although with a slightly confusing user interface (e.g. options "Adjust" and "Synchronise", which need a little thought, the words "once" and "keep" wouldn't hurt"). I don't have any issues with it so wondered if there is a "History of Changes" somewhere so I can see what's changed, have been looking on their web-site and can't find anything.

Note it didn't have a GAotD wrapper, seems to be just the installer.

Oh, it says it's version 4.3 build 810, so not that different to the previous version, which was 4.3 build 807 (I dug it out of a backup). It also came up as registered, so I didn't need the provided key, I guess the previous one is still good.