Free online tool
How to use Date Calculator
Calculate the calendar-day difference between two dates, or move a starting date forward or backward by days, weeks, months, or years. Choose the between-dates or add/subtract mode. Enter a date or the amount of time to calculate. Review the result as a date or day count. Calendar-day comparisons ignore the time of day and daylight-saving transitions.
How it works
- Choose the between-dates or add/subtract mode.
- Enter a date or the amount of time to calculate.
- Review the result as a date or day count.
Examples and common errors
Typical task
Input or situation
Choose the between-dates or add/subtract mode.Expected result or advice
Calculate the calendar-day difference between two dates, or move a starting date forward or backward by days, weeks, months, or years.Check before processing
Input or situation
Calendar-day comparisons ignore the time of day and daylight-saving transitions.Expected result or advice
Review the result as a date or day count.Frequently asked questions
Does the calculator include both start and end dates?
It reports the elapsed calendar-day difference. For inclusive counting of both endpoints, add one day to the result when appropriate.
How does adding a month work for dates near month-end?
If the target month has fewer days, the calculator uses that month's final valid date. For example, adding one month to January 31 lands on the last day of February.
Are dates sent to a server?
No. Date calculations run locally in your browser.
Is my input uploaded?
This tool processes its inputs in your browser. Your selected text or files are not uploaded to Tool Lockers.