Date Calculator
Calculate date differences, add/subtract days, find business days, and get week numbers. Fast, free, and completely private.
Calculator Mode
Date Difference Calculator
Multiple Calculations
Calculate date differences in days, weeks, months, and years instantly.
Business Days
Count only weekdays (Monday-Friday) for accurate business day calculations.
100% Private
All calculations happen in your browser. Your dates never leave your device.
How to Use
Calculate Date Difference
Enter two dates to see the difference in days, weeks, months, and years. You can also calculate business days by excluding weekends.
Add Days to a Date
Enter a start date and the number of days you want to add. The calculator will show you the resulting date with its day of the week.
Subtract Days from a Date
Enter a start date and the number of days you want to subtract. The calculator will show you the past date with its corresponding day of the week.
Find Week Number
Enter any date to find which week of the year it falls in. This follows the ISO 8601 standard (weeks 1-53).
Frequently Asked Questions
What is a date calculator?
A date calculator is a tool that helps you perform calculations with dates. You can calculate the difference between two dates, add or subtract days from a date, count business days, and find the week number for any date.
How do I calculate the difference between two dates?
Enter the first date and second date in the date difference mode. The calculator will show you the difference in days, weeks, months, and years. It will also show the number of business days (excluding weekends) between the two dates.
What are business days?
Business days are weekdays Monday through Friday, excluding weekends (Saturday and Sunday). The calculator counts only these days when calculating business day differences, which is useful for project planning and delivery estimates.
How do I add or subtract days from a date?
Select the 'Add' or 'Subtract' mode, enter your starting date, specify how many days to add or subtract, and the calculator will show you the resulting date with its day of the week.
What is a week number?
A week number is the position of a week within a year (1-53). For example, January 1st could be in week 1. This is useful for business and scheduling purposes. This follows the ISO 8601 standard.
Is my data private when using this calculator?
Yes, absolutely! All calculations happen directly in your browser. No dates are sent to any server, ensuring complete privacy and security of your personal dates.