How we calculate
Every number on this site follows the same short list of rules. Here they are, with examples.
Days until an event
A "days until" count is the number of whole days after today up to the event. Today is not counted, and the event day is not counted either.
So if an event is tomorrow, the count is 1. If it is today, the page says it is today and does not show a number.
This is the rule most people use when they count down, and it is the one every page here follows.
Sleeps, weeks and hours
A sleep is a night. The sleeps until a day equal the days until it. You sleep once before each of those days.
Weeks are whole weeks, with any leftover days shown beside them. Hours are the whole days multiplied by 24, counted from midnight at the start of today.
Hours therefore change once a day, not every hour. A countdown to a clock time is the exception, and it counts seconds.
Weekdays and work days
A count of one weekday starts tomorrow and stops the day before the event. If Christmas is a Friday, that Friday is not in "Fridays until Christmas".
A weekend is one Saturday and Sunday pair. Work days are Monday to Friday, and public holidays are left in unless the page says they are taken out.
The business days calculator removes national public holidays and names each one, so you can see what was taken out.
Time zones
The page you receive is built in New York time. It holds the right answer for the day that the page was built, in that zone.
When the page loads in your browser, a small script reads your time zone from your device and recounts. A visitor in Sydney can see tomorrow's number while New York is still on today's.
You can pick another zone on a page, and your choice is remembered on your device only. The recount happens in your browser and sends nothing to us.
Months, years and leap days
Months are calendar months. January 31 to March 1 is one month and one day. The month is counted to the same day number, or to the last day if that number is missing.
Years work the same way. February 29 plus one year gives February 28 in a common year.
Leap years follow the Gregorian rule. A year divisible by 4 is a leap year, unless it divides by 100 and not by 400.
Where holiday dates come from
US federal holidays follow the US Office of Personnel Management. UK bank holidays follow GOV.UK, and Canadian and Australian holidays follow their governments.
Easter uses the Western church calendar. Lunar holidays, such as Lunar New Year, Ramadan, Diwali and Hanukkah, use published tables. Seasons use astronomical data from the US Naval Observatory.
When a holiday falls on a weekend and the day off moves, the page counts to the holiday itself and notes the observed day.
Worked example
Say today is Wednesday, October 28 and Christmas is on Friday, December 25. The count is 58 days, because there are 58 whole days from October 29 to December 25 when counted from tomorrow.
Fridays until Christmas is 8, and the page lists each Friday from October 30 to December 18. The Friday on December 25 is not included.
Weekends until Christmas is also 8, because each weekend is a Saturday and Sunday pair that ends before the day itself.
Corrections
We check the numbers with automated tests, and we compare dates with the sources listed on each page. Errors can still happen.
If you find one, write to us on the contact page and say which page and which number. We aim to fix confirmed errors quickly.
What a day means here
A day is a calendar day in the zone you are in, from midnight to midnight. It is not a block of 24 hours counted from the moment you open the page.
This matters on the days when clocks change, which are 23 or 25 hours long. A calendar day is still one day, so the count stays whole.
It also means the answer on this site only changes at midnight, which is what most people expect from a day count.
Dates in the past
Pages about the past, such as how long ago a year was, use the same rules in reverse. The count is the number of whole days between that date and today.
Years and months are shown as calendar units, with the days left over shown beside them. The days figure is the exact total.
Questions people ask
Why is my number different from another site?
Sites differ on whether today is counted and which time zone they use. We never count today, and we count in your own zone.
Do the numbers change during the day?
Day counts change at midnight in your time zone. Hours, minutes and seconds on a clock-time page change as you watch.
Are public holidays removed from weekday counts?
Not on the weekday count pages. They are removed on the business days calculator, which names each holiday it takes out.
How do you handle daylight saving time?
Counts use calendar days and real clocks in your zone. A day with a clock change is still counted as one day.