The gap between two dates, several ways
Count the days between two dates, broken down into weeks and months. For deadlines, notice periods and countdowns.
Counting days by hand across a month boundary is where mistakes happen, especially when February or a leap year is involved.
The first question is always whether both endpoints count. A 30-day notice period starting on the 1st runs to the 31st, not the 30th — the same off-by-one that ruins contract dates.
What this calculator shows
- Total days between the two dates
- The same span expressed in weeks and in months
- Correct handling of leap years and uneven month lengths
What to keep in mind
- Counts the days between the dates, so the start day itself is not included.
- Month counts are calendar-based; months genuinely vary between 28 and 31 days.
FAQs
Does the result include both the first and last day?
It counts the interval, so the start date is not included. Add one if your contract counts both endpoints.
How many working days is that?
This is a calendar count. As a rough guide, multiply the weeks by five, then subtract public holidays yourself.
Why can two spans of 'one month' differ in days?
Because months are unequal. January to February is 31 days; April to May is 30. Anything billed monthly inherits that variation.
Can I calculate a date in the past?
Yes. Put the earlier date second and the tool reports the span; the direction does not break the arithmetic.
Worked example
A quarter of the year
Input: 1 January to 1 April 2026
Output: 90 days
Note: In a leap year the same span is 91 days. Any calculation assuming a fixed 90-day quarter is wrong one year in four.