Add or Subtract Days From a Date

What date is 90 days from today? What was the date 6 weeks ago? Enter a start date, choose an amount and a unit, and the calculator gives you the resulting date and its weekday.

Adding months and years

Adding days and weeks is exact: every day is the same length on the calendar. Months are different, because they vary from 28 to 31 days. When you add months, the calculator keeps the same day of the month. If that day does not exist in the target month, it uses the last day of that month. So January 31 plus one month is February 28 (or February 29 in a leap year), not March 3.

Adding a year to February 29 works the same way and gives February 28 of the following year.

Typical uses

• Deadlines: a 30-day return window or a 90-day notice period.
• Pregnancy and health: 40 weeks from a given date, or a follow-up in 6 weeks.
• Travel: visa-free stays such as 90 days, or the last day of a 180-day period.
• Finance: payment terms such as net 30 or net 60.

For deadlines that count only working days, use the business days calculator instead.