Day Counter
Show the math
What Your Result Means
- Days: The exact number of calendar days between your two dates. This is an absolute value — swapping start and end gives the same number.
- Business days: Weekdays only (Monday through Friday). Public holidays are not excluded, so the actual working-day count may be slightly lower.
- Weeks: Total days divided by 7, shown as a decimal for precision.
- Months and years: Approximations using average lengths (30.44 days per month, 365.25 days per year). For an exact calendar breakdown, use the date calculator.
- Hours, minutes, seconds: The day count multiplied out to smaller units, assuming full 24-hour days from midnight to midnight.
How This Calculator Works
You enter a start and end date. The tool converts both to midnight timestamps, subtracts, takes the absolute value, and divides by 86,400,000 milliseconds to get whole days. Business days are counted by walking through each day and checking whether it falls on a weekday. Months and years use fixed averages (30.44 and 365.25) rather than calendar-aware arithmetic, so they are approximations.
Quick Questions
Does this include public holidays in business days?
No. The business-day count excludes Saturdays and Sundays only. National and local holidays are not removed because they vary by country and region. Subtract any holidays that fall on weekdays manually.
Why are months and years approximate?
Calendar months range from 28 to 31 days, and years from 365 to 366. This tool divides by fixed averages (30.44 and 365.25) for a quick estimate. For an exact calendar-aware breakdown, use the date calculator.
Does the count include both the start and end dates?
It measures the gap between the two dates. Same-day inputs return 0. If you need to include both endpoints (for example, counting "Day 1" through "Day 5" as five days), add 1 to the result.
Can I count backward?
Yes. The calculator uses the absolute difference, so it does not matter which date is earlier. The result is always a positive number.
Sources
- MDN Web Docs — JavaScript Date (timestamp arithmetic and date handling)
- Wikipedia — ISO 8601 (week numbering and date format standards)
Method & review
Estimate only. Results reflect your inputs and standard formulas. Double-check important decisions independently.