Date Calculator
Add or subtract years, months, weeks, and days from any date.
Date calculator
Time to add
Result Date
Enter a start date to calculate the result date.
How it works
Choose a starting date, select Add or Subtract, then enter the number of years, months, weeks, and days. The calculator applies the calendar units in order and returns the resulting date.
- Start date:
- August 15, 2026
- Operation:
- Add
- Days:
- 90
- Result date:
- November 13, 2026
Questions
How does the Date Calculator work?
Choose a start date, select Add or Subtract, then enter years, months, weeks, and days. The calculator applies those calendar units in order and shows the resulting date.
Can I subtract time from a date?
Yes. Select Subtract, then enter the amount of time to move backward from the start date.
What happens when I add one month to January 31?
February does not have 31 days, so the result is the last valid day of February: 28 in a common year, or 29 in a leap year.
How are leap years handled?
Leap years are included in the calendar calculation. Adding a year to 29 February lands on 28 February when the next year is not a leap year. Adding days across late February includes 29 February when that day exists.
Can I combine years, months, weeks, and days?
Yes. You can enter any combination of those units. Empty fields are treated as zero.
Does the order of years, months, weeks, and days matter?
Yes. The calculator applies years first, then months, then weeks, then days. Because months vary in length, that order can change the result compared with applying the units in a different sequence.
Can I calculate dates in the past?
Yes. Subtract time from any start date, or choose a start date in the past and add time from there.
Does the calculator store my dates?
The calculator does not require an account or saved profile. Dates stay in your browser for this page session and are not sent to an IngoHub account or API.