A spare monitor tends to fill up with whatever was opened last: a chat window, a half-read article, a terminal nobody is watching. Turning it into a second monitor clock gives that screen one job it does well, and it removes the small, constant distraction of checking the time in a taskbar corner. The time becomes something you glance at rather than something you go looking for.

This article covers getting a browser window onto the right display and into fullscreen, keeping it visible above other windows, dimming it so it does not glare at you all evening, and deciding what the screen should actually show. The fullscreen display mode is the page built for this, since it fills the panel with nothing but digits.

What Makes A Good Second Monitor Clock?

Legibility at a glance and stillness the rest of the time. A second monitor clock is peripheral by definition: you are looking at the main screen, so the spare one has to be readable from the corner of your eye without ever competing for attention.

That rules out a few things. Small digits in a browser window with tabs and a bookmarks bar above them are not readable peripherally. Neither is a bright white panel beside a dark editor, which fatigues your eyes within an hour. The useful configuration is large light digits on a dark background, filling the panel, with no chrome and no motion beyond the seconds changing.

How Do You Set Up A Second Monitor Clock?

Drag a browser window onto the second display and press the fullscreen key. On Windows and Linux that is F11 in Chrome, Edge and Firefox; on macOS it is Control plus Command plus F. The window fills whichever screen it was on when you pressed the key.

Two details save some fiddling. First, move the window before going fullscreen rather than after, because dragging a fullscreen window between displays is awkward on every operating system. Second, use a separate browser window rather than a tab in your main window, so the clock is not one accidental keystroke away from being replaced by something else. A second monitor clock in its own window can be left alone for weeks. Browser-specific fullscreen behaviour is covered in getting a fullscreen clock in every browser.

Keeping A Second Monitor Clock Above Other Windows

Fullscreen on a dedicated display is the simplest form of always-on-top, because nothing else is ever placed there. If the second screen has to share space with other windows, the practical options are an installed web app window, an always-on-top utility, or a picture-in-picture style floating window.

Installing the page as a web app is usually the cleanest route. Browsers built on Chromium offer an install option that opens the page in its own window with no tab strip and no address bar, and that window appears in the taskbar or dock as a separate application, so it can be assigned to a display and left there. It also survives a browser restart independently of your ordinary tabs. Some window managers and third-party utilities add a genuine always-on-top toggle, which is worth having if the second monitor clock shares a screen with a chat client or a dashboard.

Dimming, Burn-In And Battery

A clock is a static image, and static images are what cause OLED burn-in. On an OLED panel, digits left in one position for hundreds of hours can leave a faint permanent ghost, so it is worth reducing the risk before it becomes visible.

Sensible precautions, in rough order of usefulness:

  • Lower the brightness: a second monitor clock needs far less brightness than a working display, and dimming reduces both burn-in risk and eye strain.
  • Use dark backgrounds: light digits on black light only a fraction of the pixels, which cuts wear and power on an OLED considerably.
  • Avoid a permanently fixed layout: if the display will run for months, a layout that shifts position slightly, or a screen that is switched off overnight, spreads the wear.
  • Watch the battery on laptops: a second screen kept awake is a meaningful drain, and a clock that prevents sleep prevents the machine from saving power at all.

On a desktop with a mains-powered monitor, the battery question disappears and only burn-in and eye comfort remain. On a laptop or tablet pressed into service as a bedside or desk clock, the trade-off is real, and it is examined in screen wake lock and battery.

What Should A Second Monitor Clock Display?

Whatever you glance at most, and nothing else. A clock that displays everything at once forces the eye to search, which defeats the point of a peripheral display.

  • Hours and minutes: the default for a desk or wall display. Large, calm, and readable from across a room.
  • Seconds: worth adding when you are timing something loosely or waiting for a scheduled start, and easy to read at a distance if the digits are sized properly.
  • Milliseconds: only for genuine timing work. A churning third decimal is exhausting in peripheral vision and unreadable anyway.
  • A countdown: a live countdown timer is often more useful than the time itself during a focus block, a meeting or a cooking session.
  • Elapsed time: a stopwatch with laps answers how long this has taken, which a clock cannot.

Twenty-four hour format is usually the better choice on a shared or peripheral display, since there is no AM or PM to misread at a glance.

Stopping The Screen From Sleeping

A second monitor clock that has gone to sleep is worse than no clock, because you look at a black panel and then have to reach for the mouse. Two things can blank the display: the operating system's own sleep and screensaver settings, and the browser doing nothing to prevent them.

The Screen Wake Lock API is the browser's answer. A page can request a screen wake lock and the operating system will keep the display on while that page is visible; the lock is released automatically when the tab is hidden or the window is minimised, which is a sensible default. On a permanently installed display it is often simpler to change the operating system's power settings directly and let the machine keep the screen on regardless of what any page requests. If the display is genuinely unattended, in a lobby or a corridor, the approach in kiosk clock displays is more robust than relying on a browser API alone.

Conclusion

A second monitor clock is a small change with a disproportionate effect: one screen with one job, large enough to read from the corner of your eye and quiet enough to ignore the rest of the time. Move a dedicated browser window to the spare display, go fullscreen with F11 or Control-Command-F, dim it, prefer light digits on a dark background to limit burn-in, and show only what you actually glance for. Keep the screen awake through the browser or through system power settings, whichever suits the machine. Set up your second monitor clock with the fullscreen display mode, or see the other displays on livetime.now.