Date Calculator: Add or Subtract Days
Pick a date and enter how much time to add; see the date it lands on.
Results
Please enter valid values.
“What is the date 90 days from today?” comes up with invoice terms, trial periods, return windows and visa stays. With months of 28, 30 and 31 days, counting by hand invites mistakes.
The calculator adds or subtracts days, weeks, months and years, and shows the weekday and week number of the result.
How to calculate Date
- Choose the start date.
- Choose whether to add or subtract.
- Enter the years, months, weeks and days, then read the resulting date.
Date formula
Result = start date ± (years, months) ± (weeks × 7 + days)Adding months keeps the day of the month; if it does not exist, the last day of that month is used
Date example
Adding 90 days to 4 October 2026 gives Saturday, 2 January 2027. Adding one month to 31 January gives 28 February, because February has no 31st.
Date: common questions
Is adding one month the same as adding 30 days?
No. One month takes you to the same day of the next month, and months vary from 28 to 31 days. Use whichever your contract specifies.
What if the date falls on a weekend?
The calculator returns the calendar date. Legal and commercial deadlines often roll to the next working day — check the rule that applies to you.
Can I go back in time?
Yes. Choose “Subtract” to find, say, the date 200 days ago.