The Stopwatch Home Page


Stopwatch does what its name implies - enables hand timing much like a physical stopwatch. It can also be used as a countdown timer.

Stopwatch has millisecond accuracy and no artificial limit on hours. Stopwatch runs on UNIX, Windows, and MacOS.

Stopwatch normally runs as a standalone program. To run it this way, download and install it. You can also run stopwatch inside the browser, if you have the Tcl plugin.


Press "start" to start the stopwatch and "stop" to stop it. "record" records the current time and selects it so that it can readily be pasted into other programs. Recorded times are marked with an L for "lap" or T for "total". When stopped, you can cut/paste/edit the time by hand and set it to any valid time. "zero" resets the time to zero. Holding down the shift key while pressing record or zero, records and then zeros the time.

Time moves forward or backward according to the Run menu. By default, time is stopped automatically when either the lap or total time reaches zero. To disable the automatic stop, unselect Run -> Stop At Zero.


source This single file is all you really need.
complete distribution A full distribution for people who want the README, HISTORY, and other unnecessary stuff.


There is no installation step (such as "configure" or "Make"). Once downloaded, simply run stopwatch with wish or any Tk-enabled interpreter. If you're unfamiliar with wish or Tk, download the Tcl/Tk distribution from the Tcl Developer Xchange.


This page describes stopwatch version 3.5.


Stopwatch is free.

Copy and Reuse Information

Stopwatch is in the public domain.


Stopwatch requires Tcl/Tk 7.5 or later. Millisecond timing is available when using Tcl 8.3 or later.

By default, the maximum time is just over 596 hours (about 25 days). The range may be increased (to about 68 years) by disabling the millisecond timer. To disable the millisecond timer, unselect Run -> Milliseconds.

Contact Info

Don Libes,
National Institute of Standards and Technology
100 Bureau Drive, Stop 8264
Gaithersburg, MD 20899-8264

Names of companies and products, and links to commercial pages are provided in order to adequately specify procedures and equipment used. In no case does such identification imply recommendation or endorsement by the National Institute of Standards and Technology, nor does it imply that the products are necessarily the best available for the purpose.
Last modified: Thu Mar 18 12:25:44 EST 2004