The Tube at this hour is a matter of joining the right crowd rather than choosing a seat, and getting through it depends on leaving at a specific minute. This page counts down to 6:45 am precisely — the moment to leave, the moment to touch in, or the moment a meeting on the other side begins.
The figure on this page comes from your own device's clock, checked continuously and recalculated every second against 6:45 am. There is nothing to press and nothing to set up first — the count is already running by the time the page has finished loading, and it keeps going while you are looking at it.
Said out loud, 6:45 am usually comes out as quarter to seven in the morning rather than as a string of digits. Spoken and written time diverge more than people expect, which is worth remembering when somebody tells you a time over the phone and you are trying to match it against something printed.
Common questions
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 6:45 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.
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 6:45 am, set an alarm as well and treat this page as the running total.