Online clock, full screen
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What is this fullscreen clock?
The AlarmClock24 fullscreen clock is a web clock designed for long sessions: keep the time visible on a second monitor while you work, study, stream, or present. It displays the current time in giant digits that scale to any screen size, with an optional analog dial.
Everything runs in your browser with no installation. The clock reads your device's local time, so it is always as accurate as your computer or phone. It keeps working with the tab in the background, and a single click on "Fullscreen" hides every browser bar for a distraction-free display.
How to use it
- Open the clock page — the current time appears instantly.
- Pick your style: digital with seconds, or an analog dial.
- Choose one of 6 color themes; your choice is remembered between visits.
- Press "Fullscreen" to hide the browser chrome. Press Esc to exit.
Who uses a fullscreen clock?
Teachers and speakers keep it on a projector so the audience sees the time without a phone check. Programmers and writers park it on a second monitor to track focus sessions. Pilots of long calls use it to watch meeting lengths. And at night, the dimmed theme turns the page into a discreet bedside clock that doesn't burn your eyes in the dark.
Frequently asked questions
Does the clock keep updating if I switch tabs?
Yes. The display refreshes every second from your device's clock, and the update loop uses absolute timestamps, so it stays accurate even after the tab is throttled in the background.
Can I use it at night without being blinded?
Yes. The dark themes and the dedicated night-dim option reduce brightness for dark rooms. Your theme choice is saved in your browser for the next visit.
Does it work offline?
Yes. Once the page is loaded, the clock needs no connection — it reads the time locally from your device.