Writing and time tools
Date Calculator
Count days between dates or add and subtract days and weeks. Includes leap years, optional end-date inclusion and weekday counts with clear calendar rules.
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How to use this tool
1. Choose Days between dates or Add or subtract days. Enter a start date, or select Use today for start.
2. For a difference, enter the end date and choose whether to include it. For a shifted date, choose a direction, amount and days or weeks.
3. Calculate and review the counting convention. Copy or print the result before changing inputs.
Calendar dates, not elapsed hours
The calculator represents each date in UTC for arithmetic so local daylight-saving transitions cannot add or remove a calendar day. It uses the Gregorian calendar throughout 1600–9999, including years before some countries adopted it.
Worked example
28 February 2024 to 1 March 2024 spans 2 days when the end date is excluded, or 3 counted dates when it is included. Adding 2 calendar days to 28 February 2024 gives 1 March 2024 because 2024 is a leap year.
Questions and assumptions
What is included?
By default the start is included and the end is excluded. Including the end counts both endpoints. Monday–Friday counts include public holidays and are not holiday-adjusted business days. No jurisdiction-specific deadline rules are applied.
Limits and date shifting
Use real dates from 1600 to 9999 and shifts from 0 to 1,000,000 days or weeks, provided the result stays in that date range. One week is seven calendar days. Month/year shifts and elapsed-hour calculations are outside this tool’s scope.
Sources and further reading
Built and maintained by Custom Logic. Page updated .