Guides/Business days between dates

Business days between dates

Calendar days count every day including Saturday and Sunday. Business days (weekdays) usually mean Monday–Friday only. Holidays are extra exclusions that depend on your country and workplace.

Weekday counting method

1. Get the total calendar days between start and end (decide if the end date is inclusive).
2. Walk each day or use week math: full weeks contribute 5 business days each.
3. Add leftover weekdays in the partial week; skip Sat/Sun.
4. Subtract public holidays that fall on weekdays if your policy requires it.

Rough estimate: × 5/7

For long spans without holidays: business days ≈ calendar days × (5 ÷ 7). Example: 28 calendar days × 5/7 = 20 business days. Fine for planning; not exact for short ranges that start mid-week.

Worked examples

1. Mon 3 → Fri 7 (same week): Tue–Fri if exclusive of start, or Mon–Fri = 5 business days if you count both ends as workdays — define the rule first.
2. Fri 1 → Mon 4: calendar span is short; business days between (excluding weekends) may be 0 or 1 depending on inclusive rules. Always state whether start/end count.
3. 10 calendar days spanning one weekend: typically8 weekdays (10 − 2).
4. Two full weeks: 14 calendar days → 10 business days (absent holidays).
5. SLA “3 business days” from Wednesday: reply by Monday (Thu, Fri, Mon) — not Saturday.

Common mistakes

• Treating “in 7 days” the same as “in 7 business days.”
• Forgetting holidays that land on weekdays.
• Mixing inclusive and exclusive end dates when comparing vendor SLAs.

Calendar days first

The freeDate Difference Calculatorreturns calendar days; subtract weekends (and holidays) yourself for working-day counts. Related:days between dates·days until a date·add N days.