Date Difference Calculator
Find the exact span between any two dates — in years, months, weeks, days, hours, and working days.
What this calculator returns
Most spreadsheets can subtract two dates and give you a number of days. That is rarely what people want. When you ask "how long between these two dates?" you usually mean a human-readable answer: 2 years, 4 months and 11 days, or 118 working days. This page gives you both the human-readable breakdown and every common unit at once.
Years, months, days
The years/months/days breakdown follows the same standard borrowing rule used in legal documents. If the end date\u2019s day-of-month is smaller than the start date\u2019s, we borrow days from the previous calendar month — using the actual length of that month, not a flat 30. The result is what you would write on an immigration form, a contract, or a project closeout report.
Working days
Working-day counts treat Monday through Friday as work days. We do not subtract public holidays, because they vary by country, state, and even employer. If your project tracking requires holiday-aware counts, take our working-day total and subtract the number of holidays that fall in the range — that will be precise to the country.
Use cases
- Project planning — "How many working days do I have until launch?"
- Contracts and notice periods — "From notice given to last day, how many days, and how many of those are working days?"
- Holiday and travel planning — "We are away from May 3rd to May 17th — how many nights is that?"
- Subscription and lease audits — "Exactly how long has this contract been running?"
- Anniversary calculation — "How long ago was the wedding, in years, months, and days?"
Privacy and accuracy
Like every calculator on this site, no data leaves your device. The math is done in your browser using the proleptic Gregorian calendar with full leap-year rules. There is no rounding to whole years and no hidden conversion to a different calendar system — the numbers you see are the numbers you would compute by hand if you were patient enough.
Frequently asked questions
What does this date difference calculator do?
It returns the exact span between two calendar dates in years, months, weeks, days, hours, minutes, and working days. It also tells you the day of the week for each date.
How are working days counted?
We count Monday through Friday between the two dates inclusive on the start date and exclusive on the end date. We do not subtract public holidays — those vary by country and region.
Can I include or exclude the end date?
The total day count is exclusive of the end date by convention (a stay from Monday to Friday is four nights). The week and month breakdown uses calendar arithmetic and does not depend on inclusivity.
Will this work with dates before 1900 or after 2100?
Yes. The proleptic Gregorian calendar is used, so any date from year 1 onward is calculated correctly. Future dates have no upper limit other than what your browser can represent.