Date Calculator
Add or subtract days, weeks, months, or years to any date to find a past or future date.
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How to use this calculator
- 1
Select your start date using the date picker.
- 2
Choose whether to add or subtract time.
- 3
Enter the amount and select the unit (days, weeks, months, or years).
- 4
The resulting date appears instantly with the day of the week.
Frequently asked questions
Can I add multiple units at once?
Each calculation handles one unit at a time. Run the calculator multiple times or use the Date Difference calculator for complex scenarios.
How are month additions handled?
When adding months, the calculator preserves the day of month where possible. For example, adding 1 month to January 31 gives February 28 (or 29 in a leap year).
Does it account for leap years?
Yes — leap years are handled automatically for all calculations.
Adding and subtracting dates
Why date arithmetic is tricky
Unlike numbers, dates have irregular intervals — months vary from 28 to 31 days, and leap years add an extra day. Simple multiplication fails; you need calendar-aware arithmetic to correctly count forward or backward in time.
Common use cases
Date arithmetic is essential for project deadlines (30 days from today), contract terms (90 days from signing), subscription renewals (1 year from purchase), and legal notice periods. This calculator handles all these scenarios accurately.
Learn more from an authoritative source:
WikipediaDate Difference Calculator
Find the exact number of days, weeks, months, and years between two dates.
Time Calculator
Add or subtract two time values in hours, minutes, and seconds.
Working Days Calculator
Count the number of working days (Monday–Friday) between two dates, excluding weekends.
Business Days Calculator
Calculate a future or past date by adding or subtracting a number of business days (Mon–Fri).
Birthday Calculator
Discover your age, the day you were born, days until your next birthday, and your zodiac sign.
Retirement Calculator
Find out when you can retire based on your date of birth and target retirement age.
Results are estimates for informational purposes only and do not constitute professional financial, medical, legal, or technical advice. Read full disclaimer →