Day Till Calculator
Countdown Calculator works out Seconds remaining and Minutes remaining from What to count, Target date and Target time. The default figures on this page give countdown of 358 days; change any entry and the result, the working and the sources update together.
Your figures
Updates as you typeHow this is worked out
6 steps
- Reference instant: 2025-01-01 00:00:00.
- Target instant: 2025-12-25 00:00:00.
- Signed difference = target - reference = 30931200 s.
- 30931200 s = 358 d 0 h 0 min 0 s (86400 s per day, 3600 s per hour, 60 s per minute).
- Calendar walk 2025-01-01 to 2025-12-25: 0 year(s), 11 month(s), 24 day(s).
- Decimal years = 358 / 365.2425 (mean Gregorian year) = 0.980171.
Its 5 worked examples are re-run on every release, last on 15 September 2026. What changed
Sources and references
3 sources
What the Countdown Calculator calculates
Time remaining until a target date and time - days, hours, minutes and seconds, plus the calendar breakdown - and the finish time of a timer of a given duration.
How to use this Countdown Calculator
Enter What to count, Target date, Target time and Count from date. Seconds remaining updates as you type, and “Use a worked example” loads checked figures you can adjust. Change one figure at a time to see what drives the result.
How the result is worked out
Open “How this is worked out” beside the result for the step-by-step calculation behind Seconds remaining, Minutes remaining and Hours remaining.
The method follows ISO 8601-1:2019, Date and time - Representations for information interchange, Howard Hinnant, chrono-Compatible Low-Level Date Algorithms (days_from_civil) and TC39 Temporal proposal - PlainDate and Duration.
Days from New Year to Christmas 2025 example
With What to count: until, Count from date: 2025-01-01, Target date: 2025-12-25, the calculator returns Whole days remaining: 358, Hours remaining: 8592, Whole calendar years: 0. This example is checked against an independent source in the test suite.
What you can compare
Change one input at a time to see how it affects Seconds remaining, Minutes remaining and Hours remaining. The inputs you can vary are What to count, Target date, Target time, Count from date, Count from time and Timer hours.
Results are general information, not financial, tax, legal, medical or engineering advice. Check any decision that matters with a qualified professional.
See something wrong? Report a problem with this calculator
Frequently asked questions
How long until time calculator?
Time remaining until a target date and time - days, hours, minutes and seconds, plus the calendar breakdown - and the finish time of a timer of a given duration. Open “How this is worked out” beside the result to see each step for your own figures.
How much time until it's 11?
On the figures this page opens with, the countdown is 358 days. No single number fits everyone: it follows What to count, Target date and Target time, so enter your own above and the answer updates as you type.
What information do I need for the Countdown Calculator?
You need What to count, Target date, Target time, Count from date, Count from time, Timer hours, Timer minutes and Timer seconds. The page opens with default figures that give countdown of 358 days, so you can see the scale before entering your own.
What does this Countdown Calculator show?
It shows Seconds remaining, Minutes remaining, Hours remaining, Days remaining (decimal), Weeks remaining (decimal), Whole days remaining, Hours after the whole days and Minutes after the whole hours, with the working and any warnings for your entries.
Can I check how the Countdown Calculator result was calculated?
Yes. The “How this is worked out” section shows the calculation steps, and the sources section identifies the references used for the method.