Date Calculator
Days, weeks, months — instantly. Find the time between any two dates or add time to a date.
How the Date Calculator Works
Two modes are available. Use 'Between dates' to find the exact number of days, weeks, months, and years separating any two dates. Use 'Add/Subtract' to calculate a future or past date by adding or subtracting a specific amount of time from any starting date.
The result also shows the day of the week, which is useful for planning events, deadlines, and appointments.
Frequently Asked Questions
Does the calculator include both the start and end date?
The calculator counts the number of days between the two dates, not including both endpoints. For example, from January 1 to January 3 gives 2 days. If you need to count both the start and end date (inclusive), simply add 1 to the result.
How are months calculated when months have different lengths?
The month count is calculated by comparing the calendar month and year of each date, not by dividing the day count by 30. This means January 31 to March 1 counts as 1 month (not ~1.4). For precise legal or financial calculations, verify with an accountant or legal professional.
What happens when I add months to a date that doesn't exist in the target month?
JavaScript's date handling rolls over to the next month automatically. For example, adding 1 month to January 31 gives March 2 (or March 3 in a leap year), because February 31 doesn't exist. This is standard behavior consistent with most date tools and spreadsheet applications.
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