Heartbeat Clock is a clock, world clocks, a stopwatch, and a timer that install straight from the web. It opens instantly, runs offline, and keeps nothing about you on a server.
Works on iPhone, Android, and desktop. Nothing to download from a store.
Every tool that belongs on a clock app, and none of the ones that don't.
Your local time at a glance, with the day of year, ISO week number, UTC offset, and Unix time underneath.
Pick from 37 time zones and see each one marked as today, tomorrow, or yesterday relative to where you are.
Centisecond resolution with laps and splits, and a screen that stays awake while it runs.
Nine presets or your own duration, with a chime and a buzz at zero. Anchored to the clock, so backgrounding it doesn't slow it down.
12 or 24-hour, seconds on or off, light or dark or system, haptics, wake lock. Remembered on your device.
Add it to your home screen and it opens full-screen with its own icon — no browser chrome, no tab.
The details that usually give a web app away have all been dealt with.
There is no app store step. Your browser does the installing.
Go to clockapp.heartbeat.me in your phone's browser. It works fully as a normal page too, if you'd rather stop there.
iPhone: tap Share, then Add to Home Screen. Android: tap Install when it offers, or Add to Home screen from the menu.
It gets its own icon and launches full-screen. From then on it works with or without a connection.
It's free, it needs no account, and it will still be there when your signal isn't.
Open Heartbeat Clock