Date Difference Calculator
The number of days between two dates.
Input sheet
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Counting the span between two dates by hand is error-prone once month lengths and leap years enter the picture. This tool returns the exact number of days between any two dates, plus the equivalent in weeks, months, and years.
How it works
Takes the absolute difference between the two dates in days.
The result is the absolute difference, so the order of the two dates does not matter — you get the same positive span whether you enter them earliest-first or latest-first.
Week, month, and year figures are derived from the day count using average lengths (7 days, 30.44 days, and 365.25 days) so they account for leap years over long spans rather than assuming a flat 30-day month.
Days = |end date − start date| in days; Weeks = days ÷ 7; Months = days ÷ 30.44; Years = days ÷ 365.25.
Worked examples
From 2026-01-01 to 2026-12-31. → 364 days — about 52.0 weeks, 12.0 months, and 1.00 years.
364 ÷ 7 = 52.0, 364 ÷ 30.44 ≈ 12.0, 364 ÷ 365.25 ≈ 1.00.
From 2024-06-01 to 2026-06-01. → 730 days — about 104.3 weeks and 2.00 years.
Two years with no leap day in the span total 730 days; 730 ÷ 365.25 ≈ 2.00.
Tips & gotchas
- Decide whether you need inclusive counting (both endpoints) — for project deadlines, add one day to the raw difference to include the start day.
- For payroll or rental periods, the month figure is an average; check the actual calendar months if exact billing dates matter.
- Use this to track milestones — days sober, days since a project launch, or a countdown to an event.
- The day count ignores time of day, so two dates are a whole number of days apart regardless of hours.
FAQ
Does it count both the start and end dates?
No — it counts the gap between them. If you need both endpoints counted (an inclusive range), add one to the day result.
Are weekends and holidays excluded?
This returns calendar days, including weekends and holidays. For business-day counts you would need to subtract weekends and any holidays separately.
Why is a year shown as 365.25 days?
Averaging in the quarter-day that leap years correct keeps the year and month figures accurate across long, multi-year spans.
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