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Calculators / Date & time / Date difference
Date difference calculator
Count calendar days and weeks between two dates.
On this page
Calendar days364
Weeks52
Calculator controls
How to calculate
Count calendar days and weeks between two dates.
Days = (end − start) in UTC calendar days
Worked example
Start date: 2026-01-01; End date: 2026-12-31.
Calendar days: 364 ; Weeks: 52 .
Assumptions and limits
Excludes the end date. Negative values mean the end is before the start. No business-day or holiday adjustment.
Results are rounded for display; calculations use unrounded values. Read our calculation methodology.
Understanding the result
The result is the calendar-day interval between the two dates. Equal dates have a difference of zero.
When this tool is useful
Measure elapsed calendar time between two events.
Understanding your inputs
| Input | What to enter |
|---|---|
| Start date | Enter the value in the format shown. |
| End date | Enter the value in the format shown. |
Frequently asked questions
Are weekends excluded?
No. Every calendar day is counted. This is not a business-day or holiday calculator.
Does the result include both dates?
No. It measures the interval. For an inclusive count of dates from start through end, add one when the end is not earlier than the start.