Date Difference Calculator
Calculate the exact days between two dates — plus weeks and approximate months — for project timelines, billing periods and travel planning.
Your details
Days between
How to use this calculator
- 1
Choose a start date and an end date.
- 2
Read the absolute day count between them.
- 3
Use the weeks and approximate months for a quicker sense of span.
Understanding your results
Day count is the number of midnights between the two calendar dates. Weeks are full 7-day blocks. Months are an approximation using 30.4375 days (the average Gregorian month), so they are useful for planning, not legal billing unless your contract says otherwise. To move a date forward or backward by a known interval, use the Date Add Calculator.
Frequently asked questions
Are both dates inclusive?
This calculator reports the day difference between the two midnights. Crossing from Jan 1 to Jan 2 is 1 day.
What if the end date is earlier?
You still get a positive day count, with a note that the end date is before the start date.
Why are months approximate?
Months vary in length. The months figure uses an average-month conversion so you can estimate longer spans quickly.
How do I calculate the number of days between two dates?
Pick your start and end dates above. The tool counts whole midnights between them and also shows weeks and approximate months.
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Disclaimer
CalcPilot's results are estimates for everyday and planning use. Verify critical decisions with an authoritative source. Review our calculation methodology and full disclaimer.