24 Hour Timer

About this twenty-four hour timer

This twenty-four-hour countdown runs entirely in your browser. A long-duration timer for extended sessions where you want a single end signal. There is nothing to install, nothing to sign up for, and no data is uploaded when you start, pause, or reset.

How long is 24 hours? 1,440 minutes, or 86,400 seconds — one full day. A 24 hr countdown is usually about a deadline rather than a task: a fast, a fermentation, a trial period, or a challenge that ends at a fixed moment tomorrow.

A twenty-four-hour timer is a long stretch — use it when you want a single end signal far in the future rather than a series of shorter intervals. It works for extended study sessions, long meditation sits, slow-cooked recipes that do not need an intermediate check, or simply marking when a specific time will have passed.

Long timers are more exposed to browser background throttling and accidental tab closures, so keep the page in the foreground where possible. For anything time-critical or safety-related, use a dedicated kitchen, phone, or system timer instead.

How to use this timer

• Press Start (or the spacebar) to begin the countdown.
• Press Pause (or the spacebar again) to hold the current time.
• Press Reset (or the R key) to return to 24:00.
• When the timer ends, a short tone plays. Click, tap, or press any key to stop it.
• Use the sound toggle to mute the alert — your preference is remembered on this device.

Tips for accurate timing

• Keep this tab visible. Modern browsers slow down background tabs to save power, which can delay the end alert.
• On mobile, keep the screen awake or plug the device in for long sessions.
• For anything safety-critical, use your device's built-in system timer rather than a web page.

Related timers: 2 hour timer or 30 minute timer.

Looking for a different duration? Browse the TimerZen home page or type any whole-number duration into the URL (for example, /45-minute-timer/, /90-second-timer/, or /2-hour-timer/).

Last reviewed on April 24, 2026.