Enter a start date and specify years, months, weeks, and days to add or subtract — the Add Days Calculator returns your resulting date along with the day of the week and total days added. Choose whether to add or subtract, mix and match time units freely, and see your new date right away.
Resulting Date
--
Day of the Week
--
Total Days Added/Subtracted
--
Expressed As
--
Select your start date, choose 'Add', then enter the number of days (and optionally years, months, or weeks) you want to add. The calculator will display the resulting date and the corresponding day of the week.
Yes. Simply switch the operation to 'Subtract' and enter your time values. The calculator will count backward from your start date by the specified amount.
Absolutely. You can enter any combination of years, months, weeks, and days simultaneously. The calculator adds them all up and applies the total to your start date.
Yes. The calculation uses JavaScript's built-in Date object, which correctly handles leap years and varying month lengths when adding months or years.
One week equals exactly 7 days. Using the weeks field is simply a shortcut — entering 2 weeks and 3 days is the same as entering 17 days.
When you add months and the resulting month has fewer days than the start day (e.g., adding 1 month to January 31st), JavaScript's Date automatically rolls over to the next month. For example, January 31 + 1 month becomes March 2 or 3 depending on the year.
Yes, this is one of the most common uses. Enter today as your start date, choose 'Add', and enter the number of days until your deadline to find the exact due date.
The start date is entered using a standard date picker, so the format is handled automatically by your browser. Results are displayed in a clear Month Day, Year format along with the day of the week.