Date Calculator Tool | Calculate Business Days, Time Spans & Date Differences

Date Calculator Tool

Calculate time differences, business days, and add/subtract dates with our free online calculator.

Date Calculator

Calculate Days Between Dates

Select the beginning date
Select the ending date

Add or Subtract Time from a Date

Select your starting date

Calculate Business Days Between Dates

First day of business period
Last day of business period

Add Business Days to a Date

Beginning work date
Working days to add

Calendar

About Date Calculations

Date Difference Calculator

The date difference calculator helps you find the exact amount of time between two dates. This powerful tool calculates days, weeks, months, and years between any two calendar dates. It's perfect for:

  • Calculating age with precision
  • Determining project durations
  • Measuring contract periods
  • Finding time elapsed since significant events
  • Planning for future dates and deadlines

Our calculator handles leap years automatically, ensuring accurate results every time.

Adding or Subtracting Time

The time addition/subtraction tool allows you to calculate a future or past date by adding or subtracting specific time periods from any starting date. This feature is invaluable for:

  • Planning deadlines and milestones
  • Calculating subscription end dates
  • Scheduling future appointments
  • Determining historical dates for research
  • Setting reminder periods for important tasks

You can combine years, months, weeks, and days for precise date calculations that account for varying month lengths and leap years.

Business Days Calculator

The business days calculator is essential for professional planning, computing only working days between dates while excluding weekends and optionally holidays. This specialized tool helps with:

  • Project management timelines
  • Estimating delivery dates
  • Calculating payment due dates
  • Planning business processes and workflows
  • Determining business turnaround times

Our calculator supports U.S. federal holidays and provides a clear breakdown of business days for accurate workplace planning.

Leap Years Explained

A leap year has 366 days instead of 365, with an extra day added to February (February 29). This calendar adjustment keeps our calendar in alignment with the Earth's revolutions around the sun. The rules for leap years are:

  • Years divisible by 4 are leap years
  • Century years (ending in 00) are not leap years unless divisible by 400
  • For example, 2000 was a leap year, but 1900 was not

All our date calculators automatically account for leap years to ensure accurate results for any date range you select.

How to Use These Calculators

Simply select the appropriate tab for your calculation need, enter the required dates, and click the calculate button. For date differences, you'll see a comprehensive breakdown of the time span in multiple units. When adding or subtracting time, you'll get the resulting date with its day of the week. Business day calculations will show working days with optional holiday exclusions.

These tools are free to use and work on all modern devices and browsers. No registration required!

Frequently Asked Questions

To calculate the exact days between two dates, select the "Date Difference" tab, enter your start and end dates in the respective fields, and click "Calculate Difference." The calculator will show you the precise number of days between these dates, accounting for leap years and month lengths automatically.

Calendar days include all days of the week, while business days typically only include Monday through Friday, excluding weekends and holidays. For project planning and work-related deadlines, business days provide a more accurate timeline since they reflect actual working days. Our Business Days Calculator makes this distinction clear in your planning.

Our calculator handles all date calculations with high precision, accounting for leap years, varying month lengths, and other calendar complexities. It can accurately calculate time spans of any length, from a single day to multiple centuries, following the Gregorian calendar system used worldwide.

Business days calculations are essential for professional planning as they reflect actual working time. When scheduling project timelines, delivery estimates, or payment deadlines, counting only business days gives you a realistic timeframe that excludes weekends and optionally holidays when work typically doesn't occur. This leads to more accurate planning and expectations.

This calculator works with calendar dates without considering time zones. For basic date calculations (days, months, years between dates), time zones don't affect the results. If you need precise hour-by-hour calculations across time zones, you may need a specialized time zone calculator that accounts for local time differences and daylight saving time changes.

Related Calculation Tools

Time Calculator

Add and subtract hours, minutes, and seconds. Convert between different time formats and calculate time differences.

Use Tool

Age Calculator

Calculate exact age from birth date to present or any other date. Get precise years, months, weeks, and days.

Use Tool

Countdown Timer

Create countdowns to important dates and events. See days, hours, minutes, and seconds remaining.

Use Tool