Full Screen Clock
A full screen clock shows the time so large that you can read it across the room. Pick a style and color, start, done. Everything runs in your browser, with no app and no sign-up.
Source: MDN – Fullscreen API. Updated: .
How it is calculated
Sometimes the time should be the only thing on the screen: at a desk, in a seminar room or beside the bed. This page turns a laptop, tablet or phone into a big clock, digital or analog, with or without seconds and date.
How the full screen clock works
- Choose a digital or analog clock, 24 or 12-hour format and a color. The preview shows it at once.
- Click “Start full screen clock”. The clock fills the screen.
- A click, a tap or the Esc key ends the display.
What it is handy for
- Desk and stage: a big clock helps you keep track of time in talks, lessons and exams.
- Bedside: red on black dazzles least in the dark. Turn the display brightness down.
- Old tablet or phone: with a charging cable it becomes a desk clock. The page keeps the screen awake where the browser supports it.
Kind to the screen
The display shifts by a tiny amount every minute. This protects OLED screens, where a permanently identical image can burn in.
Honest limits
The clock shows your device’s time and time zone, not that of an atomic clock. To check whether your device clock is accurate, use the “Exact time” tool. Whether true full screen and keeping awake work is up to the browser; on iPhone, Safari does not allow full screen for web pages, so the clock fills the window. A power-saving mode can still switch the screen off.
Frequently asked questions
How do I show the time full screen?
Pick a style and color and click “Start full screen clock”. A click, tap or Esc ends the display.
Does the screen stay on during the display?
Usually yes: where the browser supports the Wake Lock API, the screen stays awake. Otherwise your device’s screen lock applies.
Can I show an analog clock full screen?
Yes. Choose “Analog clock”. It shows hour, minute and second hands and, if you like, the date.
Which color is best at night?
Red on black or amber on black. These colors dazzle less in the dark than white. Also lower the display brightness.
Is the clock accurate?
It uses your device’s clock. The “Exact time” tool shows how accurate that is by comparing it with a time source.
Sources and legal basis
- MDN – Fullscreen API
- MDN – Screen Wake Lock API
- W3C – Screen Wake Lock API
- MDN – Intl.DateTimeFormat (localised time and date)
As of: · Editorial policy
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