Date Difference Calculator
Calculate the number of days, weeks, months, and years between two dates
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How to Use
- 1 Enter your start date — Use the date picker or click "Today" to set the start date. This is the beginning of the period you want to measure.
- 2 Enter your end date — Select the end date for your calculation. You can swap the dates using the swap button if needed.
- 3 View your results — See the total number of days between your dates, with a detailed breakdown showing years, months, weeks, hours, minutes, and seconds.
- 4 Toggle options — Enable "Include end date" to count both start and end dates, or toggle "Business days only" to exclude weekends from the count.
- 5 Add or subtract days — Use the add/subtract calculator to find a date by adding or subtracting days, weeks, months, or years from any starting date.
Frequently Asked Questions
How is the date difference calculated?
The calculator uses precise date arithmetic to find the exact difference between two dates. It accounts for leap years, varying month lengths, and time zones. The primary result shows total days, with additional breakdowns for years/months/days, weeks, and time units.
What are business days?
Business days (also called working days or weekdays) are Monday through Friday, excluding weekends. When you toggle "Business days only," the calculator counts only weekdays and shows how many weekend days are excluded from the total.
Should I include the end date in my calculation?
It depends on your use case. If you're counting the number of days between two dates (exclusive), leave it unchecked. If you're counting both the start and end dates as part of the duration (inclusive), enable "Include end date." For example, a vacation from Jan 1-3 is 2 days exclusive or 3 days inclusive.
What are calendar facts?
Calendar facts provide additional context about your date range, including the day of the week for both dates, their week numbers in the year, and how many leap year days (February 29th) fall within the range.
Can I calculate a future date?
Yes! Use the "Add or Subtract Days" section at the bottom. Enter a starting date, choose how many days/weeks/months/years to add or subtract, and the calculator will show you the resulting date.
Is my data private?
Absolutely. All calculations happen directly in your browser using JavaScript. No dates or personal information are sent to any servers or stored anywhere. Your privacy is completely protected.