Date Calculator

Calculate days between dates or add/subtract days from any date.

Days Between
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Weeks
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Months
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Years
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Important Legal Disclaimer

For Educational and Informational Purposes Only: This calculator provides estimates and approximations based on the information you provide. Results are not exact and should not be relied upon for any official, legal, financial, medical, or professional purposes.

No Professional Advice: The calculations and information provided do not constitute financial advice, legal advice, tax advice, medical advice, or any other form of professional consultation. Always consult with qualified professionals (financial advisors, attorneys, tax professionals, healthcare providers, etc.) before making important decisions.

No Liability: By using this calculator, you acknowledge that the results are estimates only. We make no warranties or guarantees about the accuracy, completeness, or reliability of the calculations. Use of this tool is at your own risk.

This disclaimer complies with applicable U.S. federal and state laws regarding the provision of informational tools and the limitation of liability for educational resources.

Abbreviations Explained

Business Days: Weekdays (Monday-Friday), excluding weekends and holidays.

Calendar Days: All days including weekends and holidays.

Leap Year: A year with 366 days, occurring every 4 years (with exceptions).

Date Range: The period between two specific dates.

Duration: The length of time between two dates or events.

How the Calculation Works

Date calculation methods:

Days Between Dates:

Days = (End Date - Start Date) in milliseconds / (1000 × 60 × 60 × 24)

Example: From Jan 1, 2024 to Jan 31, 2024 = 30 days

Add/Subtract Days:

New Date = Start Date + (Days × 24 hours × 60 min × 60 sec × 1000 ms)

Example: Jan 1, 2024 + 45 days = Feb 15, 2024

Leap Year Rules:

  • Divisible by 4: Usually a leap year
  • Divisible by 100: Not a leap year (exception)
  • Divisible by 400: Is a leap year (exception to exception)
  • Example: 2024 is a leap year, 2100 is not

Example Calculation: Days from March 15, 2024 to June 20, 2024:
• March: 16 days remaining (31 - 15)
• April: 30 days
• May: 31 days
• June: 20 days
• Total: 97 days