Anything due by the end of the morning brings a short burst of urgency just before the deadline lands. Knowing exactly how long is left until 11:57 am is the difference between finishing properly and rushing the last paragraph. The figure here recalculates every second, so it is never out of date.
Coming back to this page in an hour, tomorrow or next month shows exactly the same thing: however long is genuinely left until 11:57 am next comes round. There is no session to lose and nothing to configure again, because the number is worked out fresh each time from the clock on your device.
Matching what somebody said against what somebody wrote is easier with all three versions to hand: 11:57 am for everyday reading, 11:57 for anything printed in railway style, and three minutes to twelve in the afternoon for whatever was actually spoken down the phone. All three describe precisely the same point in the day, and having them side by side saves a good deal of squinting at a timetable.
Common questions
What is 11:57 in the 12-hour clock?
That is 11:57 am, or three minutes to twelve in the afternoon if you are saying it aloud. From 13:00 onwards, subtracting twelve gives the pm figure — the same moment written three different ways.
Does the number update by itself?
Yes. It recalculates every second from your device's clock, so there is nothing to refresh or restart. Whatever is on screen is the current gap to the target time, not a figure worked out when the page first loaded.
What happens if 11:57 am has already gone for today?
The count simply carries on towards the next occurrence, which is tomorrow. That rollover happens on its own — the page does not need reloading and there is nothing to reset by hand.
Which clock does it use?
Your own. It reads the local time and time zone from the device you are looking at, so the figure reflects where you actually are rather than a fixed zone written into the page.