What is the black screen with clock?
A black screen with a clock shows the time on a fully black background, dimmable far below the usual system minimum for night use.
A black field with the time in the middle and a brightness control that goes low enough for a dark bedroom. On an OLED phone the black pixels are switched off entirely, so it draws very little power and casts almost no light into the room.
That is the same panel behaviour the black screen page explains in full, and the flip clock is the version meant to be read across a room.
How do you use the black screen with clock?
Press fullscreen, drop the brightness until it is comfortable in the dark, and switch on Keep awake so it stays visible.
- Go fullscreen and drop the brightness with the slider until it is comfortable in the dark.
- Turn on Keep awake so the clock is still there at three in the morning.
- Press Escape to exit.
Will a black screen clock drain my phone battery overnight?
Very little on an OLED phone, because black pixels emit no light and draw almost no power. On an LCD the backlight stays on regardless.
The difference is in how the panels work: an OLED lights each pixel individually and a black pixel is simply off, while an LCD lights the whole panel from behind and shows black by blocking that light. Plug in anyway if you depend on the phone in the morning.
How do I make the clock dimmer than my phone allows?
Use the brightness control on this page. It dims the drawn colour itself, so it goes well below the system brightness minimum.
This is genuinely useful in a very dark room, where even the lowest system setting can be too bright to sleep next to.
Does the screen stay on by itself?
Only with Keep awake enabled. Without it the device sleeps normally and the clock disappears until you touch it.
See the flip clock for a larger, higher-contrast version meant to be read across a room.
Does this cost anything or need an account?
No. Every tool here is free, needs no sign-up, and runs in the browser with nothing to install and nothing stored.
There are no accounts, no paywalled sizes and no watermarks on downloads. See the full list of screen tools.
Will my screen stay awake while it runs?
Yes, with Keep awake switched on. It holds a browser wake lock so the display stays lit with no input until you leave.
Useful when a screensaver or clock is meant to run unattended. The lock is released as soon as you close the page.
Put this on your site
The embeddable version drops the page around it and runs the tool on its own.