Day CounterFree online other calculator — instant results, no sign-up
Count days between two dates, optionally weekdays only.
About the Day Counter
The Day Counter calculates the exact number of calendar days and business days between a start date and an end date. It is commonly used by project managers, HR teams, legal professionals, and students planning project timelines or contract deadlines.
- Start
- The beginning date of the interval (inclusive), in YYYY-MM-DD format.
- End
- The concluding date of the interval (exclusive), in YYYY-MM-DD format.
Formula and method
Total Days = (End Date - Start Date) / 86,400,000 ms Business Days = Sum of days d from Start to End - 1 where DayOfWeek(d) is not Sunday (0) or Saturday (6)
- Start DateBeginning date boundary (counted in the range)
- End DateConcluding date boundary (not counted in the range)
- DayOfWeek(d)Integer day of the week from 0 (Sunday) to 6 (Saturday)
The tool computes the total calendar days by taking the date difference in milliseconds divided by 86,400,000. It then steps through each day from the start date up to but not including the end date, incrementing the business day count whenever the day of the week is Monday through Friday (excluding Saturdays and Sundays).
Worked example
These are the calculator's starting values and the results it actually produces for them.
Inputs
- Start1970-01-01
- End1970-01-31
Results
- Total days30
- Business days22
How to use the Day Counter
- 1Enter your beginning date in the Start field.
- 2Enter your target date in the End field.
- 3The tool calculates the total elapsed calendar days between the two dates.
- 4Read the business days output, which tallies all Mondays through Fridays in that span.
Reading your result
Total days reflects the full elapsed calendar duration across the selected period. Business days represents working days, filtering out weekend days (Saturday and Sunday).
Limitations
The calculation does not include public or regional bank holidays; only standard weekend days (Saturday and Sunday) are excluded from business days. The interval is calculated on a half-open basis (start date included, end date excluded).
Common questions
Does the calculation include both the start and end dates?+
The tool uses a standard half-open date interval: the start date is included in the count, but the end date marks the end boundary and is not counted.
Are official public holidays deducted from business days?+
No. The business day counter only filters out Saturdays and Sundays. Regional, national, and religious holidays are counted as regular business days.
What happens if the start date is after the end date?+
If the start date is later than the end date, the loop condition will not run, resulting in zero business days, and the total days count may be negative or zero.
Does the calculator save my information?+
Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.
Further reading
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Results are estimates for informational purposes and are not financial, medical or legal advice.