Date Calculator

Add or subtract days, weeks, months, and years from any date. Calculate the exact difference between dates in multiple units including business days.

Add to DateSubtract from DateDate DifferenceSpecial Dates
Date Calculator
Add or subtract time from dates, calculate date differences, and find special dates

Date Calculator Features

Our comprehensive date calculator provides multiple tools for all your date calculation needs.

Add to Date

Add days, weeks, months, or years to any date. Perfect for calculating future deadlines, appointments, or event planning.

Subtract from Date

Subtract days, weeks, months, or years from any date. Useful for finding past dates or calculating historical timelines.

Date Difference

Calculate the exact difference between two dates in years, months, days, and more. Includes business days calculation.

Special Dates

Find special dates like next Monday, first day of next month, or same day next year with a single click.

Common Date Calculations

Learn how to use our date calculator for common scenarios

Project Deadline Calculation

To calculate a project deadline that's 30 business days from today:

  1. Select the "Add/Subtract" tab
  2. Enter today's date as the start date
  3. Choose "Add" as the operation
  4. Enter "30" as the amount
  5. Select "days" as the unit
  6. Click "Calculate"
  7. The result will show your deadline date

Note: For business days calculation, use the "Date Difference" tab to verify the actual number of business days.

Age or Time Passed Calculation

To calculate how much time has passed since a historical event:

  1. Select the "Date Difference" tab
  2. Enter the historical date as the start date
  3. Enter today's date as the end date
  4. Click "Calculate Difference"
  5. The result will show years, months, days, and total days passed

Payment Due Date Calculation

To calculate a payment due date that's 45 days from an invoice date:

  1. Select the "Add/Subtract" tab
  2. Enter the invoice date as the start date
  3. Choose "Add" as the operation
  4. Enter "45" as the amount
  5. Select "days" as the unit
  6. Click "Calculate"
  7. The result will show your payment due date

Finding Special Dates

To find the first day of next month:

  1. Select the "Special Dates" tab
  2. Choose "First Day of Next Month" from the dropdown
  3. Leave the base date empty to use today, or enter a specific date
  4. Click "Calculate Special Date"
  5. The result will show the first day of the next month

Frequently Asked Questions

Common questions about date calculations

How are business days calculated?

Business days are calculated by excluding weekends (Saturdays and Sundays) and major US federal holidays. This is useful for calculating work deadlines, shipping times, or contract terms that specify business days rather than calendar days.

How does the calculator handle leap years?

Our date calculator automatically accounts for leap years when performing date calculations. This ensures accurate results when adding or subtracting days, or when calculating the difference between dates that span leap years.

Why might my month calculation seem off by a day?

When adding or subtracting months, the calculator maintains the same day of the month when possible. However, if the target month has fewer days than the original date's day, the result will be adjusted to the last day of the target month. For example, adding 1 month to January 31 results in February 28 (or 29 in leap years).

Can I use this calculator for age calculation?

Yes! The "Date Difference" feature can be used to calculate age. Simply enter the birth date as the start date and today's date (or any reference date) as the end date. The result will show the exact age in years, months, and days. For a more specialized age calculator with additional features, check out our dedicated Age Calculator.