Business Days Calculator

Calculate exact working business days between two dates, or add/subtract business days from any date with optional US Federal holiday exclusions.

Working Days Settings

Mon – Fri
Total Business Days
21 Working Days
4.2 Workweeks

Total Calendar Days

31 Days

Weekend Days

10 Days

Federal Holidays

0 Days

Billable Hours (8h/d)

168 hrs

Labor Capacity & Resource Allocation

Standard Workweeks4.20 Weeks
Working Day Ratio67.7%
10-Hour Shifts210 hrs

Working Day Arithmetic & Contract SLA Compliance

Calendar days and business days are fundamentally different. Service-level agreements (SLAs), vendor payment terms (Net 30 business days), court filing deadlines, and project milestones measure duration strictly in working days, excluding Saturdays, Sundays, and observed statutory holidays.

1. Business Day Partition Formula
Business Days=(⌊ Total Days ÷ 7 ⌋ × 5)+Weekday Remainder−Observed Holidays
2. Billable Labor Hours & Workweeks Equation
Full Working Weeks
• Workweeks = Business Days ÷ 5.0
Standard Labor Hours
• Billable Hours = Business Days × 8 hrs/day
Step-by-Step Calculation Breakdown
Step 1: Evaluate 30-Day Window (Inclusive)
Total Calendar Days = 30 Days (4 Full Weeks + 2 Remainder Days)
Step 2: Subtract Weekends & Observed Federal Holidays
Weekend Days = 4 Weeks × 2 Days = 8 Weekend Days
Observed Federal Holidays in Window = 1 Holiday (e.g. Memorial Day)
Step 3: Compute Net Business Days & Labor Capacity
Net Business Days=30 − 8 − 1=21 Business Days (168 Working Hours)

US Federal Holidays Reference Table

Federal HolidayStandard RuleObservation Logic
New Year's DayJanuary 1Observed Mon if Sun / Fri if Sat
MLK Jr. Day3rd Monday in JanuaryAlways Monday
Presidents' Day3rd Monday in FebruaryAlways Monday
Memorial DayLast Monday in MayAlways Monday
JuneteenthJune 19Observed Mon if Sun / Fri if Sat
Independence DayJuly 4Observed Mon if Sun / Fri if Sat
Labor Day1st Monday in SeptemberAlways Monday
Columbus Day2nd Monday in OctoberAlways Monday
Veterans DayNovember 11Observed Mon if Sun / Fri if Sat
Thanksgiving Day4th Thursday in NovemberAlways Thursday
Christmas DayDecember 25Observed Mon if Sun / Fri if Sat

Frequently Asked Questions

How is a business day defined in this calculator?
A business day is counted as Monday through Friday. Saturday and Sunday are excluded. If you enable US federal holiday exclusions, all 11 observed federal holidays are also removed from the count. This provides an accurate working-day estimate for project planning, SLAs, payroll cutoffs, and contract milestones.
What does inclusive counting mean for date ranges?
Inclusive counting includes both the start date and end date in the evaluation window (+1 day). Exclusive counting measures the days strictly between those boundaries. Depending on your contract terms or corporate policy, toggling inclusive counting ensures compliance.
Can I add or subtract business days from a date?
Yes. Switch to 'Add / Subtract Days' mode to project forward or backward by working days only. Weekends and optional federal holidays are skipped automatically, which is ideal for 'Net 15 business days' or 'respond within 5 business days' clauses.
Which US federal holidays are excluded?
All 11 official US Federal holidays: New Year's Day, Martin Luther King Jr. Day, Presidents' Day, Memorial Day, Juneteenth, Independence Day, Labor Day, Columbus Day, Veterans Day, Thanksgiving, and Christmas Day. If a holiday falls on a weekend, its observed weekday (Friday or Monday) is excluded.
How do business days convert into billable working hours?
In standard corporate scheduling, 1 business day equals 8 working hours, and 5 business days equal a standard 40-hour workweek. The calculator computes these equivalent labor hours automatically.

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