Date Calculator
Add or subtract from a date, or count the days and business days between two dates.
Quick answer
To find a future or past date, add or subtract days, weeks, months, or years from a start date. To measure a span, subtract one date from another — this tool also counts business days (Monday–Friday). Both update live as you type.
How date math works
Adding days is exact: each day is 24 hours, so the offset lands on a precise calendar date. Weeks are multiples of 7 days.
Months and years shift the calendar field directly, because months vary in length. Adding one month to January 31 rolls into early March, since February has no 31st — use days when you need an exact count.
Business days count Monday–Friday only. Public holidays differ by country and aren’t deducted here. For longer durations in other units, see hours in a year or the time unit converter.
Frequently asked questions
What date is 90 days from today?
Use the add/subtract tool above with 90 days and "add". It applies the offset to today's date and shows the resulting date and weekday. The result updates as you change the number or unit.
How do I count the number of days between two dates?
Enter the two dates in the "days between" tool. It subtracts one from the other and shows the total days, weeks, business days (Monday–Friday), and weekend days.
What counts as a business day?
Business days are Monday through Friday. This calculator excludes Saturdays and Sundays. It does not deduct public holidays, which vary by country and region.
How are months and years added to a date?
Adding months or years shifts the calendar month or year directly. If the start day does not exist in the target month (for example, January 31 plus one month), the date rolls into the following month, which is standard calendar behavior. Use days for an exact count.