Date Difference Calculator

The difference between two dates is the elapsed time between them. We display it as a calendar breakdown plus several total-unit views.

difference = endDate − startDate

# Calendar breakdown
years   = end.year - start.year
months  = end.month - start.month
days    = end.day - start.day
# borrow if days/months are negative

# Totals derive from the millisecond difference
totalDays    = floor(|ms| / 86,400,000)
totalWeeks   = floor(totalDays / 7)
totalHours   = floor(|ms| / 3,600,000)
totalMinutes = floor(|ms| / 60,000)

1. Pick a start date and an end date — either order, the calculator shows the absolute gap.
2. It computes the raw millisecond difference and divides by the right constants to produce days, weeks, hours, and minutes.
3. A separate calendar arithmetic pass produces the human-friendly Y/M/D breakdown.
4. Business days are counted by stepping through each day and skipping Saturdays and Sundays.