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Fullscreen countdown timer for presentations and workshops

Free fullscreen countdown timer for presentations, workshops, and meetings. Set minutes and seconds, toggle repeat, and run a large on-screen clock in your browser.

What is this countdown timer?

Big Timer is a hosted fullscreen countdown clock inspired by bigtimer.net. Set hours, minutes, and seconds, start or pause the timer, and project a high-contrast display for talks, design critiques, and classroom sessions—no install required.

Countdown timer features

Core controls for a presentation-ready fullscreen timer.
  • Large fullscreen display

    High-contrast digits on a black background stay readable from across a room when you expand the timer to fullscreen.

  • Start, pause, and reset

    Run the countdown with one click, pause when you need a break, and reset to your original duration anytime.

  • Minute adjust buttons

    Use + and − to add or remove one minute before you start—handy when a session runs long or short.

  • Repeat mode

    Enable repeat to automatically restart the countdown when it reaches zero—useful for interval drills or timed rounds.

  • URL parameters

    Share a preset duration with query params like ?minutes=11&repeat=true so teammates open the same timer setup.

  • Runs in the browser

    No account, download, or extension—open the page and start timing immediately.

How to use the fullscreen timer

Three quick steps to run a countdown on screen.
  1. Set your duration

    Use the + and − buttons to set minutes, or open a shared link with hours, minutes, and seconds in the URL.

  2. Click Start

    Press Start to begin the countdown. Use Pause if you need to hold the clock, then Resume to continue.

  3. Go fullscreen

    Click Fullscreen to hide browser chrome and project the timer on a display or shared screen.

Tips for presentation timers

Get more from a large on-screen countdown.
  • 01

    Share preset links

    Add ?minutes=15&repeat=true to the URL before a workshop so every facilitator opens the same timer.

  • 02

    Enable repeat for rounds

    Turn on repeat for critique sessions, sketch sprints, or classroom exercises that run the same interval multiple times.

  • 03

    Pause instead of resetting

    If a speaker runs over, pause briefly rather than resetting—you keep the original block length intact.

  • 04

    Test fullscreen before you present

    Some browsers require a user gesture for fullscreen; click the button once while rehearsing to avoid surprises on stage.

Great for

Common fullscreen countdown use cases.
  • Conference talks and keynotes

    Keep speakers on schedule with a visible timer projected behind or beside the stage.

  • Design critiques and reviews

    Time-box feedback rounds so every participant gets equal airtime.

  • Workshops and classrooms

    Run timed exercises, breaks, and group activities with a clock everyone can see.

  • Remote meetings

    Share your screen with the fullscreen timer during standups, retros, or focus blocks.

  • Practice and rehearsal

    Rehearse a 5-, 10-, or 15-minute pitch with a countdown that matches your slot length.

Why use this browser countdown timer

Practical reasons to run timing here.
  • No account required

    Open the page and start the timer immediately.

  • Readable at a distance

    Large slab-serif digits and high contrast work on projectors and TVs.

  • Shareable presets

    URL parameters encode duration and repeat settings for quick handoff.

  • Fullscreen mode

    One click expands the timer to fill the display.

  • Client-side only

    The countdown runs locally in your browser—no server round trips.

Technical details

How the countdown timer works.
Timer engine
A one-second interval updates remaining time client-side while the timer is running.
URL parameters
Supports hours, minutes, seconds, and repeat via standard query string values.
Fullscreen API
Uses the browser Fullscreen API on the timer container element.
Typography
Roboto Slab for digit display; system sans-serif for labels and controls.
Execution
Client-side React only; no server upload or account is required.

Sources & References

Authoritative references on the browser Fullscreen API, countdown timer implementation, and presentation timing best practices.
  • The Fullscreen API provides a way to present a specific element (and its descendants) in fullscreen mode, removing all browser chrome and applying styles to the full viewport.
    MDN Web Docs — Fullscreen API

    Fullscreen API — browser-based display control: The timer uses the Fullscreen API on its container element to expand the countdown display across the entire screen, making it readable from across a conference or classroom. developer.mozilla.org/en-US/docs/Web/API/Fullscreen_API

  • setInterval repeatedly calls a function or executes a code snippet, with a fixed time delay between each call. It is commonly used to implement countdown and stopwatch functionality in web applications.
    MDN Web Docs — setInterval

    setInterval — timed execution in JavaScript: The countdown engine uses a one-second setInterval to decrement the remaining time display while the timer is actively running. Pausing clears the interval and resumes it on restart. developer.mozilla.org/en-US/docs/Web/API/setInterval

  • Presentation timers help speakers stay within allocated time slots, improving meeting efficiency and audience engagement. Visible countdowns are standard in conference talks, design critiques, and classroom settings.
    Various — Presentation timing resources

    Presentation timer best practices: Big Timer is designed for talks, workshops, and remote meetings with features like repeat mode for timed rounds, +/− minute adjustments, and URL-preset durations for consistent session timing. en.wikipedia.org/wiki/Time_management

Frequently Asked Questions

Quick answers about this tool—open a question to read more.