Date Calculator
Add or subtract time from a date, or find the time between two dates.
Quick answer: Add or subtract years, months and days from a date. For example, 90 days after January 1, 2026 is April 1, 2026. Or pick two dates to see the days, weeks and months between them.
Time between two dates
Dates are worked out from your own device's calendar day. Nothing is sent anywhere.
How to use it
- Pick the start date.
- Choose add or subtract and type years, months and days.
- The new date and its weekday appear. For the time between two dates, use the second box.
When a month is shorter, the day is held at the month end: January 31 plus one month is February 28 (or 29).
How the calculator adds and subtracts
To add a period, the calculator adds the years and months first and then the days. Adding one month to March 15 gives April 15. If the new month is shorter, the day stops at the last day of that month, so January 31 plus one month is February 28, or February 29 in a leap year. After the years and months, the days are added one by one on the calendar, so a length such as 90 days is always exactly 90 days.
How the time between two dates is found
The difference is shown as total days, and also as years, months and days. To get the months, the calculator finds the largest number of whole months that fits between the dates, and the days left over are the rest. It also shows weeks and the number of weekdays, which are the Monday to Friday days.
Examples
- January 1, 2026 plus 90 days is April 1, 2026.
- March 31 plus one month is April 30.
- From January 1 to December 25 of the same non-leap year is 358 days.
Common uses
- Due dates, warranty and return deadlines, and notice periods.
- Project plans: how many weeks to a launch date.
- Anniversaries and milestones, such as 100 days from a start date.
- School and course schedules.
For legal or contract deadlines, read the exact wording, because some contracts count business days only, or count from the day after an event.
What people use it for
- Planning and scheduling
- Homework and school
- Work and deadlines
- Travel and events
- Curiosity
Questions
How do I add days to a date?
Pick the date and type the number of days. The result shows the new date and weekday.
What is 90 days from today?
Pick today's date and add 90 days.
What happens when I add a month to January 31?
The day is held at the end of the shorter month, so you get February 28 (29 in a leap year).
Is it free?
Yes. No sign-up, no install and no limit.
Is anything saved or sent?
No. Everything runs in your browser. Only your own best score, where a page shows one, is kept on your device.
Last updated 2026-10-24. Free to use, no sign-up. Made by ficklestudio26.