Countdown calculator

Counting to a moment, not a date

Give a date and the countdown runs to midnight at the start of it, which is what people usually mean by “days until Christmas”. Give a time as well and it runs to that exact moment: useful for a deadline at five, a launch at nine, an exam at half past one.

Everything ticks on your own clock. There is no timezone picker, and that is a deliberate gap rather than an oversight: doing it properly needs a timezone list, a daylight-saving-aware conversion and a clear statement of which zone every figure is in, and getting any part of it subtly wrong produces a countdown that is confidently an hour out. Until that exists, convert to your local time first.

This one really does handle the clocks changing

A countdown measures elapsed time, so if the clocks go forward between now and your target there genuinely is one hour less to wait, and the figures reflect it. That is the opposite of what the time duration calculator does, which reads two clock times and ignores daylight saving on purpose.

Both are correct for their job. A timesheet records what the clock said; a countdown records how long you actually have to wait. Mixing them up is how an hour goes missing.

Past the target

Nothing stops at zero. Once the moment passes, the same figures keep running and read as time since, so the page doubles as a counter for how long it has been since a birthday, a start date, a move, or anything else you want to measure from. The heading changes to say which direction it is counting.

Why days, hours, minutes and seconds, and not months

Because those four are all exact and all tick smoothly. A month is not a fixed length, so a countdown counting in months would jump about as it crossed month boundaries, and two countdowns started a week apart would disagree about how long a month is. For a calendar breakdown in years and months, the date difference calculator measures between two fixed dates where that question has a stable answer.

Nothing you enter is stored or sent anywhere, including the name. The countdown is recalculated from your clock each second rather than counted down from a starting figure, so it cannot drift while the tab is open.