Real Online Timer is a free online timer and countdown clock that works instantly in your browser — set a duration, press Start, and walk away. There's nothing to install and nothing to sign up for; the timer runs entirely on your device, and no timer data is ever sent anywhere.

Most online timers quietly lose accuracy the moment you switch tabs, minimize the window, or lock your phone. This one doesn't — it's built to stay accurate to the second no matter how long it runs in the background, which matters whether you're timing a five-minute study sprint or a full hour-long meeting.

Pick a preset above, or click any digit on the main countdown to type an exact hours / minutes / seconds duration — you can also use the arrow keys or your mouse wheel to nudge a number up or down without typing at all. Press Start, and the countdown begins immediately. While it's running you can:

• Pause and resume at any time without losing accuracy.
• Add time with the quick-add buttons (+5s, +10s, +30s, +1m, +5m) — useful the moment you realize you need "just a bit longer."
• Reset back to your configured duration at any point, or useSet another timer once it finishes to start fresh.
• Save your own custom presets so a duration you use often is one click away next time.

Prefer a different look? Switch between four timer styles — Simple Timer, Big Timer, Visual Timer, and Hourglass — from the tabs above the countdown.

Short, round durations are the most common way people use an online timer, so every one below opens already set and ready to go: 1 minute, 2 minute, 3 minute, 4 minute, 5 minute, 10 minute, 15 minute, 20 minute, 25 minute, 30 minute, 45 minute, and 60 minute timers.

Each of those is just a shortcut, though — the main timer above supports any duration from one second up to 99 hours, so there's no need to hunt for the "right" preset page if yours isn't listed.

Working or teaching against a visible countdown changes how a session feels: starting gets easier ("25 minutes on this chapter" is a much smaller ask than "study until you're done"), and the session is protected from silently running long or short. The online timer for study page is built around this, with 5, 25, and 50 minute presets and a distraction-free fullscreen mode for focused work.

In a classroom, the same idea scales up: the online timer for the classroompage opens with large, high-contrast digits that stay readable from the back of the room, and fullscreen mode strips away everything except the countdown — ideal for tests, timed activities, and transitions between lessons, on a laptop, Chromebook, or interactive whiteboard.

A lot of browser timers are built by counting down a number once a second with setInterval. That approach drifts — browsers deliberately slow down or pause JavaScript timers in background tabs to save battery, so a naive countdown can end up seconds or even minutes behind the real time once you've switched away and come back.

This timer works differently: the moment you press Start, it calculates the exact clock time the countdown should reach zero and stores that instead of a number to count down. Every time the display updates — even after your laptop slept, your phone locked, or the tab was backgrounded for an hour — it re-checks the current time against that target and shows the true remaining duration. There's nothing to drift, because nothing is ever accumulated.

Press the fullscreen button (or the F key) to switch to a distraction-free, presentation-sized countdown — ideal for classrooms, meetings, workouts, or anywhere the timer needs to be readable from across the room. Start, Pause, Reset, and an exit control stay accessible the whole time; everything else steps out of the way. On devices that support it, the screen is also kept awake while fullscreen is active, so it won't dim mid-countdown.

Every timer on this site is an online timer with alarm built in — no separate app or browser extension needed. Choose from five alarm sounds (Classic, Bell, Digital, Soft, and Beep), preview any of them with the Test button before you rely on it, and adjust the volume to whatever's actually audible in your room. The 🔔 Beep when it ends checkbox next to Start gives you a one-click way to mute or unmute the alarm without opening the settings panel.

When the countdown reaches zero the alarm plays for a bounded stretch — never indefinitely — and you can stop it, restart the same countdown, add another minute, or set an entirely new timer straight from the completion screen.

Configure a duration and press Copy timer link to get a URL that opens with that exact duration already set — handy for sending a specific countdown to a class, a team, or a group chat without asking anyone to configure it themselves. Shared links never start the countdown automatically; they just load it in, ready to go.