From New Year to Christmas
1 January to 25 December 2026 is 358 days: 11 months and 24 days on the calendar, or 51 weeks and one day.
Only 256 of them are working days. The other 102 fall at weekends — nearly a third of the year.
Date difference calculator
Two dates in, and you get the gap in days, weeks, working days and calendar months. Or start from one date, add a duration, and see exactly where it falls.
Result
Fill in the fields to see your result.
How it works
There are two honest ways to count the days between dates, and they differ by one. Subtracting the dates counts the nights that pass — the answer you want for a hotel bill or a rental. Counting both endpoints counts the days you are present, which is what a project plan or a leave request means. The checkbox switches between them, and the result changes by exactly one day.
Working days are counted without a loop over every date: whole weeks contribute five days each, and only the leftover days need checking individually. Public holidays are deliberately left out, because they differ by country, by region and sometimes by employer — a single global list would be wrong nearly everywhere.
Adding months is the operation with the trap in it. There is no 31 February, so a month after 31 January has to land somewhere: this calculator moves it to the 28th, the last day that exists. Adding one month and then subtracting one month will not always bring you back to where you started, and no convention avoids that.
Formulas used
Days between
days = end − start (+1 if both endpoints count)
Working days
whole weeks × 5 + weekdays among the leftover days
Calendar breakdown
years, then months, then the days that remain
Borrowing from the previous month when the day number goes negative.
Worked examples
A project counted inclusively
The same two dates with both endpoints counted give 359 days, because the last day is a day of work rather than a night passed.
This is the count a schedule wants. The other one is what a hotel charges you for.
Ninety days from a start date
Ninety days after 1 January 2026 is Wednesday 1 April — a coincidence of a common notice period landing on a memorable date.
Switch the unit to working days and the same 90 lands much later in the year, since weekends no longer count.
Assumptions and limits
- A working day is Monday to Friday.
- Public holidays are not deducted.
- Dates carry no time of day.
- The Gregorian calendar is used throughout.
Frequently asked questions
Should I count both the first and the last day?
It depends what you are counting. Nights in a hotel, days of interest, days of hire: subtract the dates and leave the box unticked. Days of attendance, days of leave, days of a festival: tick it.
When a contract says "within 30 days", the convention is usually to exclude the first day and include the last — but read the contract, because it varies.
Are public holidays taken out of the working days?
No. Only Saturdays and Sundays are removed. Holidays differ by country and often by region, and applying the wrong set would be worse than applying none.
For a precise figure, count the holidays that fall inside your range and subtract them yourself.
Why does adding one month not always land on the same day number?
Because months are not the same length. A month after 31 January would be 31 February, which does not exist, so it moves to the 28th.
That also means adding a month and then removing one may not return you to the original date. Every calendar system has this quirk; none has solved it.
Do time zones or daylight saving affect the result?
No. Dates are handled as calendar dates with no time attached, so the clock going forward or back never adds or removes a day.
Only your device’s current date matters, and then only when you use "today" as one of the dates.
Updated