Date Calculator

Mastering Date Calculations

A date calculator is an essential tool for anyone needing to work with dates - whether for personal planning, business scheduling, or academic research. It helps you accurately determine time spans between dates or calculate future/past dates by adding or subtracting time periods.

How Date Difference Calculation Works

Calculating the difference between two dates involves several steps:

1. Convert dates to timestamps: Convert both dates to milliseconds since the Unix epoch
2. Calculate difference in milliseconds: Subtract the earlier timestamp from the later one
3. Convert to days: Divide the difference by the number of milliseconds in a day (86400000)
4. Breakdown into units: Calculate weeks, months and years from the total days

Adding/Subtracting Time Periods

When adding or subtracting time periods from a date:

• Days: Directly add/subtract the number of days
• Weeks: Multiply weeks by 7 and add/subtract days
• Months: Adjust the month value while accounting for different month lengths
• Years: Adjust the year value while maintaining the same month/day

Practical Applications

How to Use Our Date Calculator

Our tool offers two calculation modes:

1. Date Difference: Enter start and end dates to see the time between them
2. Add/Subtract: Enter a base date, choose to add or subtract, enter quantity and unit

The calculator handles leap years, different month lengths, and daylight saving time changes to provide accurate results.