Turn an old phone or tablet into a bedside clock

13 September 2026 · 6 min read

There is probably a phone in a drawer near you that still holds a charge. It has a better screen than any bedside clock sold at a similar price, and unlike those clocks it will never need its time set. The only thing standing between it and a second life is about ninety seconds of setup — and two problems nobody mentions until you hit them.

Why a web page rather than an app

Clock apps for this exist and some are good. But an app has to be found, installed, updated, and trusted, and it has to exist for whatever ancient OS version your spare device is stuck on. That last part rules out most of them. A twelve-year-old iPad cannot install anything from the App Store that was built this decade.

A web page has none of those constraints. It renders on whatever browser the device already has, it cannot go stale, and moving to a different device means typing a URL instead of repeating a setup. The trade is that a web page has less access to the system — which matters for exactly one thing, covered below.

iPhone and iPad

Open the clock in Safari, tap the Share button, and choose Add to Home Screen. Open it from the icon that appears rather than from Safari.

This step is not cosmetic. iOS Safari does not implement the Fullscreen API at all — there is no way for a web page to ask for the whole screen on an iPhone. What Add to Home Screen does instead is launch the page in standalone mode, with no address bar and no toolbar, which gets you the same result by a different route. Opened as a normal Safari tab, you will always have browser chrome eating the top and bottom of the display.

Then go to Settings → Display & Brightness → Auto-Lock and set it to Never. On iOS 16.4 and later the page can hold a screen wake lock by itself and you can skip this, but setting it costs nothing and covers older devices where the wake lock is unavailable.

Android

Open the clock in Chrome, then use the menu and choose Install app or Add to Home screen, depending on your Android version. As on iOS, launching from the icon drops the browser chrome.

Android does implement the Fullscreen API, so the clock's own full screen control works here without any of the above. The wake lock works in Chrome 84 and later, which covers almost anything still running.

If the screen still dims after a few seconds, the culprit is usually adaptive brightness or a battery saver profile overriding the request. Both live in Settings → Display and Settings → Battery.

The first problem: charging

A device used as a clock is plugged in permanently, and lithium-ion batteries do not enjoy sitting at 100% indefinitely. Held at full charge and slightly warm, a battery loses usable capacity noticeably faster than one cycled normally.

There are three honest options. Newer iPhones and Pixels have optimised or limited charging built in, which caps the cell below full when it detects a long idle period — check your battery settings, since this is often already on. Failing that, a cheap smart plug on a schedule will charge the device for a few hours a day and leave it alone otherwise. Or you can simply accept it: a battery in a device that lives permanently on a nightstand is doing no other job, and its decline costs you nothing until it swells. Check on it every few months; a phone whose back or screen has started to lift needs to be retired immediately.

The second problem: burn-in

If the device has an OLED screen — most phones from roughly 2017 onward, and iPhones from the X onward — a bright static clock left running for months will eventually leave a faint permanent ghost of itself. The pixels showing the numerals age faster than the ones around them.

Three things reduce this to a non-issue, and a well-behaved clock should do all of them for you:

A genuinely dark background. On OLED, a black pixel is an unlit pixel. It draws no power and does not age. A dark theme is not a style preference here, it is the mitigation.
Low brightness. Ageing scales with cumulative luminance. A clock at 20% brightness lasts roughly five times as long as one at full.
Moving the image. Phones shift their lock screen clocks by a few pixels every minute for precisely this reason, so no single pixel holds the same edge for hours.

LCD screens — most older iPads, budget tablets, and anything with an IPS panel — do not burn in the same way. They can show temporary image retention, but it fades. If your spare device is an LCD iPad, you can ignore this section entirely.

The physics behind all three is worth a longer look if you want to understand why phones dim the way they do rather than simply lowering opacity.

Getting the brightness right

A clock you can read from across a dark room is much dimmer than you would guess. Set it at night, in the dark, at the distance you will actually read it from — set in daylight it will be blinding at 3am.

Turn auto-brightness off if the device has it. A clock that brightens and dims as clouds pass the window is more distracting than one that is slightly wrong.

What this gets you

A silent, permanently correct clock that never needs its time set, survives power cuts, adjusts itself for daylight saving, and cost nothing. If the device is a tablet, it is legible from across a room, which is more than can be said for most alarm clocks.

Open the clock and press Always On to try it, or read about using a spare monitor the same way.