QKitBoxDate difference & age calculator
Two dates in, the full breakdown out: total days, weeks, months, years, business days — or an exact age.
Business days exclude Saturdays and Sundays; public holidays aren't accounted for. Months are counted calendar-style (same day-of-month to same day-of-month).
How it works
Total days is the raw midnight-to-midnight difference. Years and months are counted calendar-style: from Jan 15, 2024 to Mar 15, 2026 is 2 years and 2 months — the way leases and ages are quoted, not a 30-day-month approximation. Business days walk the range and skip weekends. If the end date is today and the start is a birth date, the years figure is the exact age.
Frequently asked questions
Is the end date included?
No — Jan 1 to Jan 2 is 1 day. Add one to the day count if your use case counts both endpoints (rental days, event spans).
What about time zones?
Both dates are treated as local calendar dates at midnight — no timezone shift applies to pure date differences.
Written and maintained by Steven Huang · Last reviewed October 29, 2026.