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Time Since Calculator

Enter a date and time to see exactly how long ago it was, counting up live every second. You get the breakdown in years, months, days, hours, minutes and seconds, the total in each unit, and upcoming milestones such as 10,000 days or 1 billion seconds.

Your local time. Leave as 00:00 if you only know the date.

Enter your values to see the result.
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How to use the Time Since Calculator

  1. Pick the start date and, if you know it, the time.
  2. Watch the counter: it shows the time since that moment and updates every second.
  3. Tick the fixed end date option to measure up to a specific date and time instead of now.
  4. Read the totals in each unit and the upcoming milestones.
  5. Copy the results or download the milestone table.

How elapsed time is calculated

The breakdown first counts whole calendar months from the start (12 months make a year), then the time left over after the last whole month in days, hours, minutes and seconds. When the start falls on the 29th–31st and a later month is shorter, the month ends on that month's last day.

The single-unit totals come from the exact elapsed milliseconds:

  • seconds = ms ÷ 1,000, minutes = seconds ÷ 60, hours = minutes ÷ 60
  • days = hours ÷ 24, weeks = days ÷ 7
  • years = days ÷ 365.2425 (average Gregorian year)

Handy time conversions

SpanDaysHoursMinutesSeconds
1 day1241,44086,400
1 week716810,080604,800
1 common year3658,760525,60031,536,000
1 leap year3668,784527,04031,622,400
Average year365.24258,765.82525,949.231,556,952
1 billion seconds11,574.07277,777.816,666,6671,000,000,000

Frequently asked questions

How do I calculate the time since a date?

Count the whole years and months from the start date, then the remaining days, hours, minutes and seconds up to now. Totals in a single unit come from the exact elapsed time: total seconds = milliseconds ÷ 1,000, hours = seconds ÷ 3,600, days = hours ÷ 24.

Why are total years shown with decimals?

Total years divides the elapsed days by 365.2425, the average length of a Gregorian year including leap years. The years-months-days breakdown, by contrast, uses real calendar months.

Which time zone is used?

The start and end times are read in your device's local time zone. Across a daylight saving time change the count reflects the real elapsed time, so a calendar day may contain 23 or 25 hours.

What if I enter a date in the future?

The calculator switches to a countdown and shows the time until that date, still updating every second.

When is my 1 billion seconds anniversary?

One billion seconds is about 31 years, 8 months and 8 days (11,574 days and a few hours). Enter your birth date and time to see the exact moment in the milestone table.

How many days since January 1, 2000?

Enter January 1, 2000 as the start date and the calculator shows the exact count to now. Note that 2000 was a leap year, so leap days are included automatically.

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