Date & Time Calculator
Calculate time difference between dates | Free online date calculator | Time interval calculator | Business day calculator
Calculation Results
All values are displayed without commas for full precision
Percentage of a Year (365 days)
About This Calculator
Calculator Description
This Date & Time Calculator helps you calculate the precise difference between two dates and times. It's perfect for project planning, age calculation, event countdowns, and any situation where you need to measure time intervals accurately.
The calculator provides results in multiple units (seconds, minutes, hours, days, weeks, months) and includes business day calculations (excluding weekends). You can also see what percentage of a year your time interval represents.
Frequently Asked Questions
How accurate is the calculation?
The calculator uses JavaScript's Date object for precise calculations, accounting for leap years and varying month lengths.
What does "Include end date" mean?
When enabled, the end date is included in the calculation. For example, from Jan 1 to Jan 3 would be 3 days instead of 2.
How are business days calculated?
Business days exclude weekends (Saturday and Sunday). The calculator counts only Monday through Friday when this option is selected.
Calculation Methods
The calculator uses the following conversion factors:
- Seconds: Direct milliseconds to seconds conversion
- Minutes: 1 minute = 60 seconds
- Hours: 1 hour = 60 minutes
- Days: 1 day = 24 hours
- Weeks: 1 week = 7 days
- Months: Average month length = 30.44 days
- Business Days: Weekdays only (Monday-Friday)