Countdown to a date: days, hours, minutes and seconds until (or since) a date and time in any time zone, ticking live and allowing for clock changes.
The target, set for 09:00 on Tue 27 Oct 2026 in UTC, is 29 days, 17 hours, 20 minutes and 24 seconds away.
09:00 on Tue 27 Oct 2026 in UTC is UTC+00:00, which is 2026-10-27T09:00:00Z.
UTC offsets, including daylight-saving changes, come from the IANA time zone database built into your browser.
Both instants are seconds since 1970-01-01T00:00Z.
The target date and time is turned into a single instant using its time zone's UTC offset on that day, taken from the IANA time zone database, so daylight-saving changes are included. The current time is subtracted from it and the gap in seconds is split into days of 86,400 seconds, then hours, minutes and seconds. The display updates every second, and once the target has passed it counts the time since.
People count down to launches, exams, flights, holidays and deadlines set in another country. From noon UTC on 15 January 2026 to midnight UTC on 1 February 2026 is 16 days and 12 hours, or 1,425,600 seconds.
On the day clocks go forward some clock times never happen: 02:30 on 8 March 2026 in New York is read as 03:30, the time it would be after the jump. On the day clocks go back an hour happens twice, and the advanced option picks the first or second occurrence.
Checked against: Python 3.8: datetime(2026,2,1,tzinfo=utc) − datetime(2026,1,15,12,tzinfo=utc) = 16 days 12:00:00 (test context now = 2026-01-15T12:00Z)
Checked against: Python 3.8 dateutil.tz (system tzdata 2024a): 2026-03-08 03:00 EDT = 07:00Z; minus 2026-01-15T12:00Z = 4,474,800 s
Checked against: Python 3.8 dateutil.tz.resolve_imaginary: 02:30 on 2026-03-08 in New York becomes 03:30 EDT = 07:30Z; minus now = 4,476,600 s
Checked against: Python 3.8 dateutil.tz: 2026-01-01 00:00 JST = 2025-12-31T15:00Z, 14 days 21 hours before 2026-01-15T12:00Z
Christmas Day, 25 December, is day 359 of a common year and day 360 of a leap year, so subtract today's day of the year from that number. From 1 January 2026 it is 358 days and from 1 December it is 24 days. Set the target to 25 December at 00:00 in your own time zone to see the live count down to the second.
Yes. The target's UTC offset comes from the IANA database for that exact date. In 2026 US clocks go forward at 2:00 a.m. on 8 March and back on 1 November, and EU clocks change at 01:00 UTC on 29 March and 25 October. A countdown that spans one of these changes is an hour shorter or longer than the number of days times 24.
Pick the time zone the event is announced in, not your own. Midnight on 1 January 2026 in Tokyo, which is UTC+9, was 15:00 UTC on 31 December 2025, nine hours before midnight in London. The "Target in UTC" result shows the instant being counted to, so you can compare it with a time given in UTC or GMT.
A day has 86,400 seconds (24 × 60 × 60), a week 604,800 and 30 days 2,592,000. The countdown counts every day as 86,400 seconds, the same convention as POSIX (Unix) time, which leaves leap seconds out. Total hours are shown to two decimals, so 16 days and 12 hours reads as 396.00 hours.
Accuracy depends on your inputs and the method's assumptions. Decimal arithmetic uses 50 significant digits, but estimates, numerical methods and source data can be less precise; the displayed rounding does not remove those limits. It is checked against 4 worked examples whose answers come from independent sources; for example, “Midnight UTC on 1 Feb 2026, from noon on 15 Jan” is checked against Python 3.8: datetime(2026,2,1,tzinfo=utc) − datetime(2026,1,15,12,tzinfo=utc) = 16 days 12:00:00 (test context now = 2026-01-15T12:00Z).
IANA Time Zone Database; TC39 Temporal proposal — ZonedDateTime disambiguation ("compatible").
4 worked examples with independently sourced answers ship with this calculator. They run in the test suite; you can run them here too.
Time zone converter: turn a time in one zone into local time in up to 12 others, with daylight-saving changes applied and a meeting planner grid.
Days between two dates, also as years, months and days, weeks and hours, plus business days after weekends and your own holidays.
Unix timestamp converter: epoch seconds, milliseconds, microseconds or nanoseconds to an ISO 8601 UTC date and local time, and dates back to epoch time.
Add and subtract hours, minutes and seconds from a list of durations, with the total as H:MM:SS, decimal hours, minutes and seconds.
Calculate work hours, breaks and weekly timesheets. Use dates and a time zone for overnight shifts across daylight-saving changes and repeated hours.
Military time converter: 12-hour to 24-hour time and back, how it is spoken, time-zone letters with the Zulu equivalent, and a full-day chart.
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