Date Difference Calculator
Measure the calendar gap between any two dates as years, months and days, with total days, weeks and months alongside.
Result
Enter your values and select Calculate to see the result.
How to use this calculator
- Enter a start date and an end date.
- If the end date is earlier than the start date, the dates are swapped and the result says so.
- For a simple count of days, including the option to count both end dates, use the Days Between Dates calculator.
Formula
The calculator counts whole calendar months forward from the earlier date, then counts the remaining days. Twelve months make a year.
Month-end convention: when the start day does not exist in a later month, the month is treated as complete on the first day of the following month. For example, one month after 31 January is 1 March.
Worked example
15 January 2020 to 20 March 2023
15 Jan 2020 → 15 Jan 2023 is 3 years; 15 Jan → 15 Mar is 2 months; 15 → 20 March is 5 days.
Result: 3 years, 2 months, 5 days, or 1,160 days in total (including the leap day of 29 February 2020).
Assumptions and limitations
- Months have different lengths, so “1 month” is not a fixed number of days. Total days is always exact.
- Times of day and time zones are not considered.
- Other tools may use a different month-end convention and show a one-day difference for some date pairs that involve the 29th–31st of a month.
Frequently asked questions
Does the result include the end date?
No. Like most date arithmetic, the difference from 1 January to 2 January is one day. Use the Days Between Dates calculator if you want to count both endpoints.
Are leap years taken into account?
Yes. Every date is converted to an exact day count, so 29 February is included whenever it falls within the range.