All tools
Date calculator
Days between dates, days until an event, age, working days around holidays, and week numbers, each answer with its rule. Free, with no account or uploads.
What do you want to know?
How long between two datesBest for mostDays, weeks, monthsIn years, months and days, and in days and weeks.How many days until…Christmas, a birthdayA countdown to a day or an event, with a calendar entry.How old someone isAgeIn years, months and days, with the next birthday and a few fun facts.A date before or afterAdd or take awayAdd or take away days, weeks, months or years.Working daysBusiness daysCount working days between dates, or add them, without weekends and holidays.What week is itWeek numberThe week number of any date, ISO or US, and the days it covers.
Weekend days
Saturday and Sunday. Many offices keep another; tick the days that are not worked.
Week numbers
ISO (Monday, Europe)US (Sunday)
A 29 February birthday in a common year falls on
1 March28 February
Dates follow the Gregorian calendar back to year 1, as computers do; before 1582 (1752 in Britain and its colonies) records were kept in the Julian calendar, so old dates may differ from what was written at the time.
Worked out in your browser. Nothing you type is sent anywhere; a country's holidays are read from this site's own files.
A little help along the way
Follow these steps. Every option is explained underneath. Everything runs in your browser; nothing is sent anywhere.
- Say what you want to knowHow long between two dates is the usual. The others count down to an event, work out an age, move a date, count working days or give a week number.
- Choose the datesToday is filled in. Change either date, or type an event such as Christmas or my birthday 14 March.
- Read the answerIt comes first in words, then in days and weeks, with the rule it followed under it.
- Keep itCopy the answer, add a day to your calendar, or copy a link that carries the date.
Every option explained
- The last day
- The first day is counted and the last is not, as nights are counted. Turn on Count the last day too for a holiday or a leave.
- Months
- Months are counted from the first date's day of the month. When a month has no such day, its last day is used, as calendars do.
- Working days
- Weekend days and public holidays are left out: holidays of 250 countries and their regions, from python-holidays, for 2020 to 2035. Moon-sighted holidays are estimates.
- Weekend days
- The country's usual weekend comes from your browser's data; tick your own under More options.
- Week numbers
- ISO weeks, from Monday, with week 1 holding the year's first Thursday; or the US way, from Sunday.
- 29 February birthdays
- In common years they are counted on 1 March unless you choose 28 February.
Keep going
Guides
- How many days until a date? A countdown you can share
- How to count days between two dates (with or without the end)
- What is 31 January plus one month? Adding months to dates
- How to calculate exact age in years, months and days
- How to count business days between dates, with holidays
- What week number is it? ISO and US week numbers
- How many sleeps until Christmas? The countdown explained
- How many days are left in the year?