The pips on the hour have been marking time for the best part of a century, and plenty of people still set their watch by the one o'clock signal without thinking about it. This page does something narrower and more exact: it counts down to 1:49 pm on your own device's clock, right down to the second.
Coming back to this page in an hour, tomorrow or next month shows exactly the same thing: however long is genuinely left until 1:49 pm 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.
Writing a time as 1:49 pm keeps the am or pm attached, which reads naturally in a sentence but is easy to skim past in a long list of similar entries. Writing it as 13:49 is less conversational and considerably harder to misread, which is why schedules and rotas lean that way.
Common questions
Will this alert me when the time arrives?
No. It is a live number rather than an alarm — nothing rings, buzzes or notifies you at zero. If you need to be interrupted at 1:49 pm, set an alarm as well and treat this page as the running total.
Is it affected by the clocks changing?
Only in the sense that your device is. When the change between GMT and BST happens at the end of March and October, the device adjusts and the countdown follows it without anything to do here.
What is 13:49 in the 12-hour clock?
That is 1:49 pm, or eleven minutes to two 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.