Days between two dates
Count the days, weeks and months separating any two dates.
Calculator inputs
Results
Enter your values and press “Calculate” to see the result.
In short
- What it calculates
- Count the days, weeks and months separating any two dates.
- Formula used
Days = end date − start date- Example
- From 2026-01-01 to 2026-12-31
Days between dates calculator
Counting days by hand goes wrong quickly because months have 28, 30 or 31 days. Here you only enter the two dates.
The option to include the final day matters for legal deadlines and rentals, where the last day usually counts.
How it works
The real calendar difference between the two dates is computed. Complete months are counted separately, because a month is not always 30 days.
The order of the dates does not matter: the result is always positive.
Formula
Days = end date − start date
Including the last day: days + 1
Weeks = days ÷ 7
Hours = days × 24
Worked example
From 2026-01-01 to 2026-12-31
Days: 364
Including the last day: 365
Weeks: 52
Complete months: 11
Explanation
Calendar days and working days are not the same
This is the distinction that causes the most trouble. An administrative deadline of ten working days is not ten calendar days: you must exclude Saturdays, Sundays and public holidays, and the result can stretch past a fortnight. Before counting, check which kind of day the document you are reading refers to.
Counting one too many, or one too few
Between the 1st and the 10th of a month there are nine days of difference, but ten days if you count both ends. Neither figure is wrong: it depends on the convention. Rentals, hospital stays and warranty periods usually count the starting day; interest calculations almost never do.
Financial day-count conventions
Interest is not always calculated on actual days. The 30/360 convention assumes thirty-day months and a 360-day year, common in bonds and loans, while actual/365 counts real days. Over the same period they give different figures, and both are correct within their own contract.
The ten days that never happened
In October 1582, when the Gregorian calendar was adopted, the 4th was followed by the 15th. Countries did not switch together: Britain waited until 1752 and Russia until 1918. For earlier historical dates, check which calendar your source uses.
Frequently asked questions
Should I include the last day?
It depends on the context. Legal deadlines and rental stays usually count it; a pure duration does not.
Which date format is accepted?
The browser date picker. Typed YYYY-MM-DD and DD/MM/YYYY formats are also accepted.
How do I count a working-day deadline?
By excluding Saturdays, Sundays and any applicable public holidays. Since the working calendar varies by country and locality, check with the relevant authority.
Does it work for dates before 1582?
The calculation uses the proleptic Gregorian calendar. For historical dates before the reform, check which calendar your source uses before comparing.
Need to calculate something else?
These tools are often used alongside this calculator.
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Work out effective working time after breaks, night shifts included.
Days until
Count the days remaining (or elapsed) between today and the date you choose.
Subtract days
Find out what date it was a given period before a reference date.