Add or Subtract Days
Find the date that is a given number of days, weeks, months or years from any start date.
Results
What date is 90 days from today? When does a 6-month warranty expire? What was the date 2 weeks ago? This tool adds or subtracts any number of days, weeks, months or years from a starting date. Use it for contract expirations, medication schedules, return-by deadlines, visa validity and any date arithmetic you need.
Explore all our date difference calculator tools, or browse the full time and date converters & calculators.
Frequently asked questions
Enter today's date, set the amount to 90 and the unit to days. The calculator shows the exact result date and day of the week. Roughly 90 days is about 3 months, but the exact date depends on which months are included.
Enter the start date, then add the duration in days, weeks or months. For a 30-day payment term starting January 15, set amount to 30 days to get February 14. For net-60, set 60 days.
Set the unit to months and the amount to 6. The calculator advances the month by 6 while keeping the same day. If the resulting month has fewer days (e.g., August 31 + 6 months), it adjusts to the last valid day.
Yes. Set the operation to 'Subtract (past)' and enter the number of days, weeks, months or years to go backwards. Useful for finding when a warranty started or when a 14-day return window began.
Enter today's date as the start and December 31 of the current year in our Days Between Dates calculator. Alternatively, use this tool to subtract today from December 31.