Online Stopwatch

An online stopwatch is a browser-based tool that counts up to measure a time interval. Start it on a computer, tablet or phone to track hours, minutes, seconds and hundredths of a second, and record each segment with Lap. For an alert at a specific clock time, use Online Alarm Clock For a countdown that alerts you at zero, use Countdown Timer

1. Press Start. 2. The stopwatch begins counting up immediately in hundredths of a second. 3. Press Pause whenever you need to read a frozen time, then press Start to continue.

1. Press Start to begin the run. 2. Tap Lap at every checkpoint. 3. Each row stores that segment and the running total, and you can scroll back through the complete session.

Yes. Keep this page open and switch to another tab or window. The stopwatch recalculates elapsed time from the browser clock when it updates, instead of adding delayed ticks, so background throttling does not make it drift.

It reads the high-resolution browser clock and recalculates elapsed time continuously instead of accumulating interval ticks. That prevents background drift and displays time to a hundredth of a second.

Yes. Press Full screen in the timer card. The full-screen view centers the main time, current lap and controls, which works well on a projector, external monitor or classroom screen.

Use a countdown when you know how much time is remaining and want an alert at zero. Set the duration, press Start, and let the timer count down for you. Try the Online Timer here: Countdown Timer

Yes, if you save the complete record link first. Use the sharing toolbar below the tool to save a paused snapshot, or bookmark the address after pausing. Reopening it restores the elapsed time and lap records. Reset clears the current page, but does not erase copies of links you saved elsewhere.

Yes, completely free. There is no sign-up or installation, and it works in modern desktop, tablet and phone browsers.

1. Record your laps and press Pause when finished. 2. Use a social sharing or copy-link button below the stopwatch. 3. Send or save the full URL, including the #enabled, msec, and laps parameters. The recipient sees the saved total time and every recorded split.

No. Sharing creates a paused snapshot of the time and laps at that moment, even if your stopwatch is still running. Continuing or resetting your stopwatch does not change an earlier link. Share again to send an updated record.

msec is total elapsed time in milliseconds. laps lists each split in milliseconds, from first to last, separated by dots. enabled=0 means paused; running addresses also contain start, a timestamp used to restore elapsed time. Keep these parameters together when copying a record.

Anyone with the full link can open the record. There is no password or account access control. Record data is encoded in the URL fragment; it is not saved as a server-side record. For a separate backup, use Download CSV.