Add or Subtract Days From a Date
Add or subtract days, weeks, months, or years from a date and get the exact resulting date, including the day of the week.
How this is calculated
Adding or subtracting days and weeks is plain calendar-day arithmetic. Adding or subtracting months and years counts whole calendar months, then clamps to the target month's last valid day when the starting day doesn't exist there (for example, adding a month to January 31st lands on February 28th, not March 3rd), the same convention most calendar software uses.
Frequently asked questions
How do I add days to a date?
Enter a start date, choose Add, pick a number and a unit (days, weeks, months, or years), and select Calculate. The result is the exact resulting date, including the day of the week.
What happens when I add a month to a date near the end of the month?
If the starting day doesn't exist in the target month (for example, adding a month to January 31st, since February never has 31 days), the result clamps to the last valid day of that month rather than rolling into the next month. This matches the convention most calendar software uses.
Built and maintained by Ready Utilities, founded by Cedrick Reese, a retired veteran and web developer. Every formula and convention on this site is checked against real, current sources before publishing. This calculator runs entirely in your browser, nothing you enter is sent anywhere. Spot something that looks wrong? Let us know.