Date Calculator
Add or subtract days, weeks, months or years from any date and see the result.
Add or subtract from a date
Your resulting date
Common additions from your start date
Adding weeks and months to the same start date. The rows are built from your start date.
How to add or subtract time from a date
This free date calculator adds or subtracts days, weeks, months or years from any date. It is made for anyone planning deadlines, trips, contracts or birthdays, and it shows the resulting date, the day of the week and how far away it is. There is no sign-up, and everything runs in your browser.
How do you add days to a date?
Pick a start date, choose how many days to add, and count forward on the calendar. January 1, 2026 plus 30 days is January 31, 2026, because January has 31 days. This calculator does the counting for you, including month ends and leap years, and it also tells you the day of the week for the resulting date.
What happens when you add a month to January 31?
The result clamps to the last day of the target month, because the day does not exist there. January 31, 2026 plus 1 month is February 28, 2026, since February has only 28 days in 2026, which is not a leap year according to timeanddate.com. Adding 1 month to March 31 gives April 30 for the same reason.
How do you subtract days, weeks or months from a date?
Choose subtract, then enter the amount and the unit, and the calculator counts backwards from the start date. Subtracting 30 days from January 31, 2026 gives January 1, 2026. Month subtraction clamps the same way as addition, so subtracting 1 month from March 31 gives February 28 in 2026.
How are leap years handled when adding years?
Adding years keeps the same month and day, except for February 29, which clamps to February 28 in a non-leap year. February 29, 2024 plus 1 year is February 28, 2025, and plus 4 years it is February 29, 2028 again. The calculator checks the real calendar, so leap days are never missed or invented.
Why does the calculator show the days from today?
Knowing how far away a date is helps you plan. A deadline 30 days from today needs different action than one 300 days away, and a date in the past shows how long ago something happened. The count uses today’s date in UTC, so it is the same wherever you are, and it updates every time you open the page.
What date do you get when you add time to January 1, 2026?
Adding 1 day to January 1, 2026 gives January 2, adding 1 week gives January 8, adding 1 month gives February 1, and adding 1 year gives January 1, 2027. The table below shows each result with its day of the week. Try your own start date in the calculator above to see the same pattern for any date.
| Add | Resulting date | Day of the week |
|---|---|---|
| 1 day | January 2, 2026 | Friday |
| 1 week | January 8, 2026 | Thursday |
| 1 month | February 1, 2026 | Sunday |
| 1 year | January 1, 2027 | Friday |
Frequently asked questions
What is 30 days from January 1, 2026?
January 31, 2026, which is a Saturday. Add 30 days to January 1 and you land on the last day of the month, because January has 31 days.
What is 90 days from today?
It depends on today’s date. Enter today’s date in the calculator above, choose 90 days and add, and it will show the exact resulting date and day of the week.
How do I calculate a date 6 months from now?
Enter today’s date, choose 6 as the amount and months as the unit, then add. If the target month is shorter than the start month, the result clamps to its last day, so August 31 plus 6 months is February 28 in 2026.
Does adding months always land on the same day number?
Usually, but not when the target month is shorter. January 31 plus 1 month is February 28 in 2026, because February has only 28 days. This clamping rule is how calendars and date libraries handle month arithmetic.
Can I find a date in the past with this calculator?
Yes. Choose subtract and enter the amount. For example, January 31, 2026 minus 30 days is January 1, 2026, and minus 1 year is January 31, 2025.
What day of the week was a date in the past?
Enter that date as the start date and add 0 days. The calculator shows the day of the week for it, so you can check birthdays, anniversaries and historical dates.
Does this calculator store my dates?
No. The calculator runs entirely in your browser. Nothing you type is uploaded, stored or shared.
More tools you may need
Want the gap between two dates instead? Use the Days Between Dates Calculator. Counting working days only? Try the Business Days Calculator. Working out someone’s age? Try the Age Calculator.
