Date Calculator

What does this tool do?

The Date Calculator works out the span between two dates and finds a new date by adding days to a starting one. It shows the difference in days, weeks, months and years at the same time, and gives the result date written out with its weekday. It is handy for project planning, deadline tracking, age or days-remaining calculations.

How to use it

1. Enter your values into the fields.
2. The result is calculated instantly.
3. Read or copy the result.

Two modes: difference and add

In the first mode you pick a start and end date; the tool shows the gap in four units at once: whole days, weeks (divided by 7), months (averaged at 30.44 days) and years (365.25 days, accounting for leap years). In the second mode you enter a date and a number of days to add; the result appears fully written out with the weekday. Enter a negative number of days to find a date in the past instead.

Typical use cases

Find an invoice's due date 45 days from now, the time elapsed since a contract started, or the days remaining until an event in seconds. The month and year values are given as decimals so you can clearly see approximate durations; when you need exact calendar-day precision, rely on the days column. You can copy the result date with one click and paste it into an email or your calendar.

Frequently asked questions