Date Calculator
Add or subtract days, weeks, months, or years from a date, and calculate the difference between dates.
Add or Subtract Time from a Date
Calculate Difference Between Dates
How to Use
Add or Subtract Time
- Enter a starting date in the Base Date field
- Choose whether to Add or Subtract time
- Enter the amount of time in the Value field
- Select the time unit (days, weeks, months, or years)
- Results will update automatically as you change values
Calculate Date Difference
- Enter the Start Date
- Enter the End Date
- Results will update automatically showing the difference
- The result shows the total days, as well as the breakdown in years, months, and days
- Use the swap button to quickly reverse the order of dates
Related Tools
About Date Calculator
Features
- Add or subtract time intervals from a date
- Calculate the difference between two dates
- Get results in days, weeks, months, and years
- See the breakdown of time intervals
- Calculate weekdays (Monday to Friday) between dates
- Easy date swapping for difference calculations
Common Use Cases
- Planning project deadlines and milestones
- Calculating age from birthdate
- Determining contract or subscription durations
- Planning events and appointments
- Figuring out workdays between dates
- Calculating service intervals and maintenance schedules
- Determining time spans for billing purposes
Frequently Asked Questions
How do I calculate the number of days between two dates?
Use the "Calculate Difference" section. Enter your start date and end date, then click "Calculate Difference". The tool will show you the exact number of days, weeks, months, and years between the two dates.
Can I add or subtract time from a specific date?
Yes! Use the "Add or Subtract Time" section. Select your base date, choose whether to add or subtract, enter the amount of time (days, weeks, months, or years), and click calculate to see the resulting date.
What date formats does the calculator accept?
The calculator uses a user-friendly date picker interface, so you don't need to worry about specific formats. Simply click on the date fields to open the calendar picker and select your desired dates.
Does the calculator account for leap years?
Yes, the date calculator automatically accounts for leap years when performing calculations. February 29th is properly handled in leap years, ensuring accurate results for all date arithmetic operations.
Can I calculate business days or weekdays only?
The calculator shows total days including weekends and holidays. For business day calculations, you would need to manually account for weekends and holidays based on your specific requirements and location.
What's the difference between adding months and adding 30 days?
Adding months respects the calendar structure - adding 1 month to January 15th gives February 15th, regardless of how many days are in each month. Adding 30 days simply adds exactly 30 days to the date.
Can I calculate someone's exact age using this tool?
Yes! Enter the person's birth date as the start date and today's date (or any reference date) as the end date. The tool will show their exact age in years, months, and days.
How accurate are the calculations for historical dates?
The calculator is accurate for dates within the modern calendar system (Gregorian calendar). For dates before 1582 when the Gregorian calendar was adopted, results may not account for historical calendar differences.
Can I use this tool for project planning and deadlines?
Absolutely! This tool is perfect for project planning. Calculate project duration by finding the difference between start and end dates, or determine deadlines by adding time to a start date.
What happens if I try to add months to a date that doesn't exist?
If adding months results in an invalid date (like adding 1 month to January 31st to get February 31st), the calculator automatically adjusts to the last valid day of that month (February 28th or 29th in a leap year).