Date Difference Calculator
Count the days, weeks and months between any two dates.
How to use the Date Difference Calculator
- Pick a start date.
- Pick an end date.
- See the gap in days, weeks and months instantly.
Difference = end date − start date, converted to days, weeks and months
About the Date Difference Calculator
Give this two dates and it returns the span between them: the exact number of whole days, then that figure expressed in weeks, months and years. The day count is the only exact number on the page — a straight elapsed-day count, so leap days are included automatically and you never think about which months are 31 days long. Order does not matter; the result is absolute, so the later date first gives the same answer, not a negative one.
The months and years rows are labelled "approx." for a real reason, and this is the detail most people miss. They are not calendar months. The engine divides the day count by 30.44 and 365.25 — average month and year lengths — because once you leave whole days behind, "how many months" stops having one right answer. An average is the only honest way to express an arbitrary span in months. If you need true calendar months, that is what the age calculator produces from a birth date.
Watch the endpoints. The count is the full days from start to end, so it excludes the final day. For a contract, hotel stay or leave request where both the first and last day count, add one. Use this for notice periods and countdowns; use the age calculator when the question is really "how old".
Frequently asked questions
Does the result include both the start and end day?
No. It counts the full days between them, so 1 January to 2 January is 1 day, not 2. If both endpoints count — leave requests and hotel nights are the usual cases — add one to the total yourself.
Why are the months and years marked "approx."?
Because they divide the day count by an average month (30.44 days) and average year (365.25 days). Real months vary from 28 to 31 days, so any span expressed in months is an approximation unless you anchor it to specific calendar dates.
Can the end date be before the start date?
Yes. The difference is absolute, so the order you enter them in does not change the answer. You will never see a negative result.
Are leap days counted?
Yes, automatically. The day count is a real elapsed-time calculation across the actual calendar, so any 29 February in the span is included without you doing anything.
How do I count working days instead?
This tool counts calendar days only — it has no weekend or public-holiday awareness. As a rough guide, multiply the day count by 5/7, but that ignores holidays and any partial week at either end.
Guides & articles about this tool
How to Calculate Your Exact Age in Years, Months and Days
You can calculate your exact age in years, months and days by subtracting your birth date from today’s date. This guide shows you how to do it yourself, s…