Countdown Timer
Counts down to a duration or to a target moment, with a large display, a chime and a system notification.
Two things people mean by “countdown” are both here: so many minutes from when you press start, and the time left until a particular moment. Both are computed against the system clock rather than counted, so a background tab does not slow either of them down.
A kitchen timer: so many minutes from when you press start.
0:00
When it finishes
How to use it
Choose duration or moment
A duration is a kitchen timer. A date and time is a D-day clock, counted in your own time zone.
Take a preset or type the number
The presets are the intervals people ask for by name. Minutes and seconds can also be typed directly.
Decide how it should tell you
A chime, a system notification, or both. In a hidden tab only the notification is dependable, for the same reason as the Pomodoro timer.
Common questions
Can I leave it running overnight?
Yes, as long as the tab stays open. The remaining time is the difference between two clock readings, so a laptop that slept for six hours shows the right number when it wakes.
Does the screen stay on?
While a countdown runs the page asks for a wake lock, which most current browsers grant on a visible tab. If the browser refuses it, the timer is still correct — only the screen dims.
The target time is in another country. Which zone does it use?
Yours — the one your operating system is set to. For a moment in another zone, work out the local equivalent in the world clock first, then paste that in.
Feed it from
Pomodoro Timer
Runs focus and break cycles with a notification, a session log and configurable interval lengths.
Stopwatch
Times elapsed intervals with lap splits and exports the laps as a table.
World Clock
Shows several cities at once with their offsets and marks the hours everyone is awake.
Todo List
Keeps a checklist in your browser with due dates, tags and keyboard-first editing, exportable as Markdown.
Next
These accept what this tool produces, so the result can go straight in.
Date Difference
Counts days, weeks, months and years between two dates, with a D-day view and business-day option.
Pomodoro Timer
Runs focus and break cycles with a notification, a session log and configurable interval lengths.
Stopwatch
Times elapsed intervals with lap splits and exports the laps as a table.
World Clock
Shows several cities at once with their offsets and marks the hours everyone is awake.