Date Calculator
Add or subtract days, weeks, months, or years from any date. Or find the exact number of days between two dates — instantly and accurately.
📅 Add or Subtract From a Date
What Is a Date Calculator?
A date calculator is a tool that performs arithmetic on calendar dates. There are two primary modes: adding or subtracting a duration from a date (e.g., "What date is 90 days from today?") and finding the difference between two dates (e.g., "How many days until Christmas?").
Date arithmetic is surprisingly complex due to the irregular lengths of months (28–31 days), leap years, and varying definitions of "a month" — does "1 month from January 31" mean February 28 or March 2? Our calculator follows standard calendar conventions, giving you the intuitive answer.
Common Date Calculation Scenarios
- 90 days from today — For contracts, warranties, and payment terms
- 30 days from an invoice date — For net-30 payment calculations
- 6 months from today — For subscription renewals and deadlines
- Days until a deadline — For project and event planning
- Date of birth + age in years — To find your exact birthday this year
Frequently Asked Questions
Select the "Add / Subtract Date" tab, enter your start date, choose "Add," type the number of days, select "Days" as the unit, then click Calculate Date. The result shows the exact future date.
Enter today's date as the start date, select Add, type 90 in the amount field, select Days as the unit, then click Calculate Date. The result shows the exact date 90 days from today along with the day of the week.
Yes. Select "Months" as the unit and the calculator correctly handles varying month lengths and year boundaries. For example, adding 1 month to January 31 results in the last day of February.
Yes. Every result includes the full day of the week (Monday, Tuesday, etc.) along with the calculated date, so you always know which day the result falls on.
Yes. Switch to the "Days Between Dates" tab, enter a start and end date, and the calculator returns the exact number of days, weeks, months, and years between them.
Yes, completely free with no sign-up, no ads beyond standard site ads, and no limitations. Use it as many times as you need.