Date Calculator

Frequently Asked Questions

How do I calculate the number of days between two dates?

Select the "Days Between Dates" mode, then choose your start and end dates using the date pickers. The calculator instantly shows the total days, weeks, approximate months, and years between the two dates.

How do I add or subtract days from a date?

Switch to "Add / Subtract Days" mode, select your starting date, and enter the number of days to add (positive number) or subtract (negative number). The calculator returns the exact resulting date, accounting for leap years and month boundaries.

Does the calculator handle leap years correctly?

Yes. The calculator uses JavaScript's native Date object, which correctly handles leap years (e.g. February 29, 2024). Leap years occur every 4 years, except for century years unless divisible by 400.

How do I count working days between two dates?

Enable the "Exclude weekends (working days only)" checkbox in the Days Between Dates mode. The calculator counts only Monday–Friday, skipping Saturdays and Sundays. For public holiday exclusions, you would need to subtract those manually.

How many days until a future date?

Set today as the start date and your target date as the end date in "Days Between Dates" mode. The result shows exactly how many days remain. This is useful for countdown to events, deadlines, and expiration dates.

How are "approximate months" and "approximate years" calculated?

Months use an average of 30.4375 days (365.25 / 12) and years use 365.25 days to account for leap years. These are approximations — the actual number of calendar months between two dates may differ by ±1 depending on which months are spanned.

What date format should I use?

The date picker inputs use the browser's native date format (YYYY-MM-DD internally). You can click the calendar icon to pick a date, or type directly in your local format. The calculator handles all valid calendar dates from year 1 through far future dates.