This device
It counts milliseconds on the computer
The end time is Date.now() plus the duration you set. Closing the tab can pause it. The length is stored in local storage so a refresh can resume if the end time is still in the future.
This device
The end time is Date.now() plus the duration you set. Closing the tab can pause it. The length is stored in local storage so a refresh can resume if the end time is still in the future.
Leap seconds
Everyday timers follow the machine clock. They do not insert a leap second. UTC leap seconds are a different page.
A date
Halloween, New Year, Thanksgiving, or any UTC timestamp uses the countdown tool, not this kitchen timer.