Date Add/Subtract Calculator
About Date Add/Subtract Calculator
What Is a Date Add/Subtract Calculator?
A date add/subtract calculator finds a new date by adding or subtracting a specified number of days, weeks, months, or years from a starting date. This is essential for calculating deadlines, expiration dates, due dates, contract end dates, and scheduling future events. For example, what date is 90 days from now? Or what was the date 6 months ago? This calculator answers those questions instantly.
How It Works
Select a start date, choose whether to add or subtract, enter the quantity, and select the time unit (days, weeks, months, or years). The calculator handles month-end edge cases: adding one month to January 31 results in February 28 (or 29 in leap years). It also correctly handles year boundaries and leap years.
How to Use This Calculator
Enter your starting date, select add or subtract mode, input the amount, and choose the unit. Click Calculate to see the resulting date. The output shows the new date along with the day of the week it falls on.
Frequently Asked Questions
What happens when I add a month to January 31?
Since February does not have 31 days, the result is February 28 (or February 29 in a leap year). The calculator clips to the last valid day of the target month.
Can I add multiple units at once?
Yes. You can add years, months, and days simultaneously. They are applied in order: years first, then months, then days.
Does it handle negative numbers?
Yes. You can use the subtract mode or enter negative numbers in add mode to go backward in time.
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