Does the fullscreen clock work on a monitor that is not the primary display?

Yes. Move the browser window to the second monitor before pressing F11, and the window fills that display. The operating system remembers which monitor is which, so the clock stays on the second screen across reboots.

Why does my second monitor clock stop updating when I look away?

Browsers throttle timers in hidden tabs to save CPU. `requestAnimationFrame` pauses entirely when the tab is not visible, so the second hand freezes until you look back. Keep the clock in its own window and leave that window visible (do not minimize it) and the display will keep ticking.

Can I keep the clock above other windows on the same screen?

Not with a normal browser tab. Fullscreen mode is the simplest always-on-top solution because nothing else shares the display. If the clock must share a screen, install the view as a web app so it gets its own window, then use the operating system's window management to pin it.

Will leaving a clock on my second monitor damage the screen?

On an OLED panel, static elements left in one position for hundreds of hours can leave a faint permanent ghost. Use a dark theme, lower the brightness, and if the display runs for months, switch it off overnight or let a screensaver kick in after hours. The OLED burn-in prevention guide has the full details.

Why is the clock a few seconds behind my phone?

Consumer devices are typically accurate to within a second or two of true time. The browser clock is only as accurate as the operating system clock, and the operating system syncs to an NTP server periodically. If you need second-level accuracy, sync the OS clock first. For everyday use, the difference does not matter.

What is the best way to show a clock on a TV in a lobby?

Use the kiosk mode approach: a Raspberry Pi or a small PC running a browser in fullscreen, pointed at the clock, with the wake lock enabled and the screensaver disabled. The lobby and kiosk clock display guide covers the setup step by step.

Second Monitor Clock Setup: Fullscreen Always-On Display

A spare monitor tends to fill up with whatever was opened last: a chat window, a half-read article, a terminal nobody is watching. Giving that screen a single, static job removes the small, constant distraction of checking the time in a taskbar corner. To put a fullscreen clock on a second monitor, open the clock in a dedicated browser window, drag that window to the second display, and press F11 (Windows, Linux, Chrome OS) or Ctrl+Cmd+F (macOS). The window fills whichever screen it was on when you pressed the key.

What follows 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.

Why a second monitor clock works

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. Small digits in a window with tabs and a bookmarks bar above them are not readable peripherally. The fullscreen view is built for this: it fills the panel with nothing but digits.

A dedicated time display on a secondary panel also solves a real problem with laptop lids and external screens. The panel that should be showing you the time is often showing you an email, a video call, or nothing at all. Giving it one static job means you always know where to look.

Open the clock in a separate window

Start by opening the fullscreen clock in a fresh browser window. Use a separate 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.

The display shows a large ticking clock by default. If you need a countdown or a stopwatch for a specific task, the timer tools are linked from the same view, but for a permanent clock, the default readout is what you want.

Move the window before going fullscreen

Drag the browser window by its title bar until it is on the second display. Do this before going fullscreen, not after. Dragging a fullscreen window between displays is awkward on every operating system.

If the window does not appear on the second screen, check your display settings first. On Windows, press Win+P and select "Extend" so the second monitor acts as a separate desktop rather than a mirror. On macOS, open System Settings → Displays and confirm "Extend Display" is active. On Linux, the shortcut varies by desktop environment, but the display settings panel will show the same options.

Enter fullscreen

With the window on the second monitor, press F11 on Windows, Linux, or Chrome OS. On macOS, press Ctrl+Cmd+F. The window fills the second screen completely: no tabs, no address bar, no bookmarks.

The Fullscreen API requires a user gesture (a click or keypress) to activate. You cannot force a view into fullscreen on load; the browser blocks it for good reason. The keypress must come from you, and it must happen after the view has loaded.

If F11 does not work in your browser, check the browser's view menu for a fullscreen option, or use the browser's "Install as app" feature to get a window with no browser chrome at all. The fullscreen clock in every browser guide covers the specifics for Chrome, Edge, Firefox, and Safari.

How does a second monitor clock stop the screen from sleeping?

A clock is useless if the screen goes dark after ten minutes. Most operating systems have a power setting that turns off displays after a period of inactivity, and a fullscreen clock does not count as activity.

The Screen Wake Lock API prevents the device screen from dimming or locking while the view is visible. The clock requests this lock automatically when you enter fullscreen. You will know it is active because the screen stays lit indefinitely, even though you are not touching the keyboard or mouse.

Wake lock has limits. It only works while the view is visible, and it is released when you switch to another tab or minimize the window. It also cannot override a system-level power setting on all platforms. If your OS is set to sleep after five minutes, the wake lock may not stop it. In that case, adjust the power plan in your operating system's settings so the display stays on when plugged in. The screen wake lock and battery guide explains the power trade-offs in detail.

How to dim a second monitor clock for night use

A fullscreen white clock on a second monitor is bright. It will glare at you all evening, and on an OLED panel it risks burn-in over months of continuous use.

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 the monitor's own buttons or the operating system's display settings to bring it down to a level that is visible but not glowing.

Use dark backgrounds. The clock has a dark theme that shows light digits on a black field, which is the right choice for a secondary display. Black pixels on an OLED screen are off, so a dark theme also draws less power.

For nighttime use, the view can switch to a dimmed red or amber readout that does not disrupt your sleep cycle. The dimming clock for nighttime use guide covers the options, including automatic scheduling.

Keeping a clock always on top of 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 view as a web app is usually the cleanest route. Browsers built on Chromium offer an install option that opens the view in its own window with no tab strip and no address bar. 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. Browser limitations for always-on-top behavior are real: no browser gives a normal tab the ability to float above all other windows. The app-install route is the one that works.

Troubleshooting common multi-monitor issues

The clock appears on the wrong monitor. Move the window to the correct display before pressing F11. If the operating system keeps moving it back, check that the displays are extended rather than mirrored.

The screen goes dark anyway. The wake lock is not working, or the OS power setting overrides it. Check the browser's permission settings for the wake lock API, and adjust the power plan so the display stays on when plugged in.

The clock is too small to read from across the room. The fullscreen view has a size control. Increase the digits until they are readable from your normal viewing distance. For a lobby or waiting room screen, the kiosk clock display setup guide has specific recommendations for large displays.

The clock pauses when you switch to another window. This is browser tab throttling. requestAnimationFrame stops firing in hidden tabs, so the visual update pauses even though the time value is correct when you return. Keep the clock tab visible (do not minimize it) and it will keep ticking.

The time is wrong. The browser gets time from the operating system, so if the OS clock is wrong, the browser clock is wrong. Sync the system clock with an NTP server, and the browser clock will follow. The browser clock accuracy guide explains why the display is for casual reference, not measurement.

Dedicated kiosk or Raspberry Pi setup

If the second monitor is a permanent fixture (a wall display, a lobby screen, a factory floor panel) a full desktop computer is overkill. A Raspberry Pi running a kiosk browser pointed at the clock uses a fraction of the power and cannot accidentally open a tab over the clock.

The kiosk clock display setup guide walks through the configuration, including disabling the screensaver, enabling the wake lock, and locking down the browser so nothing interrupts the display.