📅 Date Calculator
How It Works
Add or subtract days, weeks, or months from any date to find future or past dates. Use Date Calculator to answer a specific calendar or time question from the dates or times you enter.
The result is most useful when the inputs match the definitions used by this calculator. For this tool, the underlying method is: New Date = Start Date ± Number of Days. Compare the output with the worked example, then change one meaningful input at a time to see how the result responds.
Understanding Date
Date is a calendar or time calculation based on the dates, times, or conventions entered above.
Keep in mind: Calendar and time results can depend on leap years, month length, time zones, daylight-saving rules, and counting conventions. Review the date inputs and units before relying on the result.
When to Use This Calculator
Use Date Calculator to answer a specific calendar or time question from the dates or times you enter.
Practical tip: For this Date Calculator, confirm the reference date, time zone, and counting convention before comparing scenarios or using the result for an important deadline.
Formula
New Date = Start Date ± Number of Days
Example
Adding 90 days to January 1, 2026 gives March 31, 2026.