Does the countdown drift over time?

No. Every tick reads the system clock and subtracts the absolute target instant, so backgrounded tabs, sleep, and DST transitions all recover correctly when the tab returns.

What's the difference between Duration and Target Date?

Duration is "count down N seconds from now" — good for Pomodoro, cooking, and presentations. Target Date is "count down to this wall-clock moment" — good for launches, exams, and events.

Is there an audio alarm when it hits zero?

Not yet. Browser autoplay policies make reliable audio tricky. The visible finish message is always shown, and mirrored to assistive tech.

Can I save a timer for later?

Not in the current version. Refreshing clears the timer. Save the target date in your calendar and reopen the page when needed.

What happens if I set a target date in the past?

The countdown immediately shows 00:00:00 with the finish message. No error, no undefined behavior.

Can I embed this in OBS?

Yes. Add a Browser source pointing at the page URL, then crop to the stage area. Any custom background color can be keyed out for chroma transparency.

Does daylight saving time affect it?

Duration mode does not care — it is wall-clock arithmetic from now. Target Date mode uses the browser's native datetime parsing, which handles DST correctly.

Why does the first tick after returning to the tab feel sudden?

Backgrounded tabs pause the ticker to save CPU. On return, one immediate tick catches up so the display matches reality.

Can the countdown go above 99 hours?

Yes. In Duration mode the max hours input is 99, but Target Date mode has no upper bound — it will show days up to thousands if needed.

Is the timer accurate?

Accuracy is pinned to the absolute target instant, so display updates round to the nearest 250 ms tick. You may see the final second tick slightly early or late, but reaching zero is exact.

Countdown Timer Large

A fullscreen countdown timer for classrooms, livestreams, launches, and events. Set a duration or pick a target date — the page counts down to zero in giant digits.

00:25:00

What is Countdown Timer Large?

Countdown Timer Large is a zero-setup fullscreen countdown. Pick a duration or a target date and the page renders a giant DD:HH:MM:SS readout that reads from across a room. Everything runs in your browser, nothing is uploaded, nothing is installed.

It complements the other Large Text tools: Big Clock Display shows the current time, Fullscreen Text cycles through slides, and LED Scrolling Text pushes a headline across the screen. Countdown Timer Large adds “how much time is left” to the toolbox.

Under the hood, every tick reads the system clock and subtracts an absolute target instant. There’s no accumulator to drift, no animation loop to burn battery, and tab-change pauses the ticker until you return.

Tips & best practices

Duration for short sessions, Target Date for long waits. Pomodoro and cooking are duration-style. Exam day and wedding countdowns are target-date style.
Pause during interruptions. Duration mode preserves the remaining time exactly — no arithmetic needed to restart a 25-minute block after a 3-minute interruption.
High-contrast first. Pink on near-black, amber on charcoal, or lime on deep navy all read well at full-screen sizes. Pastel on pastel is unreadable no matter how large the digits.
Fullscreen early. The visual drama is in the size. OBS users should fullscreen first, then crop to the needed area.
Use the label field on Target Date. “Launch day”, “Thesis defense”, “Wedding” — the label anchors a countdown to its meaning and helps viewers orient.
Respect motion-sensitive viewers. The colon blink honors prefers-reduced-motion — no extra setup needed.

How to use it

1
Choose a mode Pick Duration for Pomodoro, cooking, or talk-time keeping; pick Target date to count down to a specific moment like a launch or exam.
2
Set the value In Duration mode, enter hours, minutes, and seconds then press Start. In Target date mode, pick a date-and-time with the native picker — the countdown begins automatically.
3
Customize and go fullscreen Adjust the digit and background colors, add a label for context, then press Fullscreen. Press Esc to exit.

Use Cases

Classroom activity timer
Put a large countdown on the whiteboard for silent reading, group work, or quizzes. Students see exactly how much time is left without a separate clock.
Presentation talk-time
Keep speakers honest at meetups and conferences. The last minute is impossible to miss on a 16:9 stage display.
Livestream intermission
Add this as an OBS browser source before returning to main content. Viewers know exactly when the break ends.
Pomodoro sessions
25-minute focus blocks with a giant visual cue. Pause and resume when an interruption arrives — no arithmetic needed.
Cooking and kitchen timer
A tablet on the counter beats squinting at a tiny oven display or fiddling with a phone lock screen.
Product launch countdown
Point a big screen at launch day. The full DD:HH:MM:SS breakdown makes the last week feel tangible.
Exam and contest day
A fullscreen countdown reduces schedule anxiety. One glance tells you how long until the test, tournament, or application deadline.
Wedding or event countdown
Stage a countdown at the venue's lobby kiosk. Guests see a dramatic visual arriving at zero.

Features

Two modes in one tool
Duration counts down from HH:MM:SS. Target Date counts down to a specific moment. Switch modes without reloading.
Auto-scaling digits
Stage binary-search font sizing guarantees the digits fill the 16:9 stage whether or not days are shown.
Start, pause, reset
Duration mode is drift-free. Pause saves the remaining time as an absolute instant, so resuming is accurate to the millisecond.
Fullscreen in one click
Tab-change pauses the ticker to save CPU. Returning recomputes from the real clock, so long background periods never cause drift.
Finish message
Type a custom prompt like Break is over or Launch. The message shows when the countdown reaches zero.
Screen-reader friendly
An aria-live region mirrors the current countdown in plain text. No visual clutter added to the stage.
Customizable colors
Separate pickers for digits and background. Defaults are high-contrast pink on near-black for legibility across a room.
Nothing uploaded
Runs entirely in your browser after the first page load. Timer state never leaves the device.

Compatible Platforms

iPhone (Safari / Chrome)
Android (Chrome / Firefox)
iPad and Android tablets
Windows (Chrome / Edge / Firefox)
macOS (Safari / Chrome)
Linux
Smart-TV browsers
Chromebook
OBS Studio (Browser Source)

Related Tools

FAQ

Does the countdown drift over time?: No. Every tick reads the system clock and subtracts the absolute target instant, so backgrounded tabs, sleep, and DST transitions all recover correctly when the tab returns.
What's the difference between Duration and Target Date?: Duration is "count down N seconds from now" — good for Pomodoro, cooking, and presentations. Target Date is "count down to this wall-clock moment" — good for launches, exams, and events.
Is there an audio alarm when it hits zero?: Not yet. Browser autoplay policies make reliable audio tricky. The visible finish message is always shown, and mirrored to assistive tech.
Can I save a timer for later?: Not in the current version. Refreshing clears the timer. Save the target date in your calendar and reopen the page when needed.
What happens if I set a target date in the past?: The countdown immediately shows 00:00:00 with the finish message. No error, no undefined behavior.
Can I embed this in OBS?: Yes. Add a Browser source pointing at the page URL, then crop to the stage area. Any custom background color can be keyed out for chroma transparency.
Does daylight saving time affect it?: Duration mode does not care — it is wall-clock arithmetic from now. Target Date mode uses the browser's native datetime parsing, which handles DST correctly.
Why does the first tick after returning to the tab feel sudden?: Backgrounded tabs pause the ticker to save CPU. On return, one immediate tick catches up so the display matches reality.
Can the countdown go above 99 hours?: Yes. In Duration mode the max hours input is 99, but Target Date mode has no upper bound — it will show days up to thousands if needed.
Is the timer accurate?: Accuracy is pinned to the absolute target instant, so display updates round to the nearest 250 ms tick. You may see the final second tick slightly early or late, but reaching zero is exact.