Online timer
Enter a duration. The clock counts toward a stored finish timestamp, not a decreasing integer.
00:10:00
Remaining time is derived from a target timestamp so background tabs stay accurate.
How it works
Start captures duration in milliseconds and adds it to Date.now(). Pause stores leftover milliseconds and resumes by creating a new finish timestamp.
Example
A 25-minute session that starts at 14:02:10 ends at 14:27:10 even if you check another tab for most of that span.
Questions
Will the timer drift in a background tab?
The end time is Date.now() plus the duration at start. If the tab is throttled, the next paint still uses that end time.
Does full screen work everywhere?
Full screen opens a large overlay and requests the browser Fullscreen API. Some browsers require a click first. Press Escape or Exit full screen to leave.
Can I change the timer color?
Yes. Pick Teal, Ink, Clay, Navy, Plum, Forest, or Gold. The choice is stored in local storage on this device.