What “Anywhere on Earth” means

AoE is the timezone UTC−12. It’s the westernmost timezone, used on the uninhabited Baker and Howland Islands, so it’s the last place where any given date ends. A deadline of “15 November, 23:59 AoE” stays open as long as it’s still 15 November anywhere on the planet. Wherever you are, if your submission is in before that, you’re on time.

AoE never changes for daylight saving. It’s always 12 hours behind UTC. In the IANA timezone database it’s called Etc/GMT+12; the sign is inverted by an old POSIX convention.

Why deadlines use it

Conferences, journals, grant programs, and hackathons draw submissions from every timezone. Picking the last timezone on Earth means no one loses part of the final day because of where they live. You don’t need to convert anything to know whether you’re late: if the date hasn’t ended for everyone, you aren’t.

23:59 or midnight?

Most calls for papers say “23:59 AoE”, so this site uses 23:59:00 as the default deadline time. The countdown reaches zero at the start of that minute. If your deadline says a different time, set it explicitly. Some submission systems close a few minutes early anyway, so don’t plan to submit in the last minute.

How this clock stays accurate

Device clocks are often off by several seconds, and sometimes by minutes. When a page loads, it asks our server for the time a few times, measures how long each answer took, and keeps the fastest one. That gives the gap between your clock and real time, usually to within a few tens of milliseconds. The page checks again every ten minutes and when you return to the tab. If your device clock is more than two seconds off, the clock band says so.

If the server can’t be reached, the clock falls back to the time in the server’s HTTP headers (accurate to about a second), and then to your device clock. The band under the clock always tells you which one you’re seeing.

Quick conversions

For anything else, use the converter.