Date Calculator
Enter a start date and a number of days to add (or a negative number to subtract) to find the resulting date.
Use a negative number to subtract days instead.
How date addition works
This calculator adds (or subtracts, for a negative number) the given number of days to your start date, correctly rolling over month and year boundaries and accounting for different month lengths and leap years.
It also shows the day of the week for the resulting date, which is useful for planning deadlines, deliveries, or events a set number of days out.
Frequently asked questions
How do I subtract days from a date?
Enter a negative number in the days field — for example, -14 subtracts two weeks from your start date.
Does this account for leap years?
Yes, the calculation uses real calendar arithmetic, so leap years are handled automatically and correctly.
Can I use this to count business days only?
This calculator counts every calendar day, including weekends. Use a work days calculator if you need to exclude weekends from the count.