Day Counter

Count the calendar days or business days (Monday-Friday) between two dates.

Free to use · Instant results

Calculator Inputs

Start year

The 4-digit year of the start date.

Start month

The month of the start date (1-12).

Start day

The day of the start date (1-31).

End year

The 4-digit year of the end date.

End month

The month of the end date (1-12).

End day

The day of the end date (1-31).

Count business days only (Mon-Fri)

When on, the headline result excludes weekends. No public holidays are excluded.

Calendar Days: 7
Business Days: 5

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How It's Calculated

Formula

\text{calendarDays} = \dfrac{\text{UTC}(\text{end}) - \text{UTC}(\text{start})}{86{,}400{,}000},\quad \text{businessDays} = \#\{\text{Mon-Fri in } (\text{start}, \text{end}]\}

Both dates are normalized to UTC calendar-day values before counting. Calendar days counts every day that passes from the start date up through the end date — the same day-count policy used by the Date Difference calculator (Jan 1 to Jan 2 counts 1 day). Business days counts how many of those same days fall on a Monday through Friday, excluding Saturday and Sunday. This version has no public-holiday calendar: a business day here strictly means 'not a weekend day,' not 'not a statutory holiday.' An end date earlier than the start date is a validation failure — it is never silently swapped.

Worked Examples

Full week: Jan 1, 2026 (Thursday) to Jan 8, 2026 (Thursday)

Normalize both dates to UTC calendar-day values.
Calendar days: 7 days pass from Jan 1 to Jan 8.
Of those 7 days (Jan 2-8), 5 fall on Monday-Friday: Fri, Mon, Tue, Wed, Thu.
Result: 7 calendar days, 5 business days.

Weekend crossing: Fri Jan 2, 2026 to Mon Jan 5, 2026

Calendar days: 3 days pass (Jan 3, 4, 5).
Of those 3 days, only Jan 5 (Monday) is a business day.
Result: 3 calendar days, 1 business day.

Frequently Asked Questions

Does business-day mode exclude public holidays?

No. This version only excludes Saturdays and Sundays. There is no public-holiday calendar, so statutory holidays are still counted as business days.

What happens if I enter the same date for both start and end?

The result is 0 calendar days and 0 business days.

What happens if I enter an end date before the start date?

The calculator reports a validation error instead of silently swapping the two dates.

Why is Jan 1 to Jan 2 counted as 1 day and not 2?

The count reflects the number of calendar days that pass between the two dates, consistent with the Date Difference calculator, not the number of dates included in the range.

Does this calculator handle leap years correctly?

Yes. Calendar dates are validated against the real Gregorian calendar, including leap years.