Two tools: count the days between dates, or find the date a number of days, weeks or months away.
How the days are counted
The calculator counts calendar days from the first date to the second, the same way you'd count on a calendar: from Monday to the following Monday is 7 days. It doesn't include the end date unless you tick the box, which adds one.
days = end date − start date (+1 to include the end date)
Working days are Monday to Friday. Weeks are shown as whole weeks plus leftover days, and the years/months/days figure is how you'd describe an age or a notice period.
Adding months and years
Months have different lengths, so "one month later" can't always land on the same day number. When it can't, the date moves to the last day of the month: 31 January + 1 month = 28 February, and 29 February + 1 year = 28 February.
Common uses
Deadlines and notice periods — 30, 60 or 90 days from a letter or contract date.
Countdowns — days until a holiday, exam, wedding or due date.
Working days — delivery estimates and payment terms that skip weekends.
Ages and anniversaries — years, months and days between two dates.
Questions people ask
How do I count the days between two dates?+
Subtract the earlier date from the later one. The calculator counts calendar days, so from 1 October to 31 October is 30 days. Tick "include the end date" if you want to count both the first and last day (31).
What counts as a working day?+
Monday to Friday. Public holidays aren't removed because they differ by country and region, so subtract any that fall in your range.
What date is 90 days from today?+
Use the "add or subtract" tool: it starts on today's date, so pick 90 days (or tap the 90 days shortcut) to see the date and weekday.
How are months added to dates like 31 January?+
If the target month is shorter, the date moves to that month's last day: 31 January plus one month is 28 February (29 in a leap year).
Does it handle leap years?+
Yes. Every calculation works on real calendar dates, so 29 February is counted in leap years and clocks changing for daylight saving never add or lose a day.