Date Difference & Business Days Calculator

Calculate total days, years/months/days, weekdays vs. weekends, and net working days between two calendar dates.

Exact Calendar Duration
0y 9m 16d (289 days)
207 net business days • 82 weekend days
Total Calendar Days 289 days
Net Working Days (Mon–Fri) 207 days
Weekend Days (Sat & Sun) 82 days
Duration in Weeks 41 wks, 2 days
Inputs
Beginning date (YYYY-MM-DD).
Ending date (YYYY-MM-DD).
Whether both boundary dates count as full days.
days
Optional number of weekday public holidays to subtract from working days.
Results & Graph
Exact Calendar Duration
0y 9m 16d (289 days)
207 net business days • 82 weekend days
Total Calendar Days
289 days
Exclusive of end date
Net Working Days (Mon–Fri)
207 days
Before public holidays
Weekend Days (Sat & Sun)
82 days
Duration in Weeks
41 wks, 2 days

Calendar Interval Composition (Days)

Net Business Days vs. Weekend Days vs. Excluded Holidays
Graph 1 • Measured Values • Calendar Interval Composition (Days) Net Business Days vs. Weekend Days vs. Excluded Holidays
Net Business Days (Mon–Fri): 207 daysWeekend Days (Sat–Sun): 82 daysExcluded Holidays: 0 days Net Business Days (Mon–Fri) 207 days Weekend Days (Sat–Sun) 82 days Excluded Holidays 0 days
Graph 2 • Calculated Values Compared Values retain their calculator-defined labels and units.
Net Business Days (Mon–Fri) 207 days Weekend Days (Sat–Sun) 82 days Excluded Holidays 0 days
Graph 3 • Calendar Span: Business, Weekend & Excluded Days Counts are shown as proportions of the calculated date interval.
Net Business Days (Mon–Fri): 207Weekend Days (Sat–Sun): 82Excluded Holidays: 0 2026-01-01 → 2026-10-17 • 289 days
Summary: Out of 289 calendar days, 207 are net working days and 82 are weekend days.
Summary: Between 2026-01-01 (Thursday) and 2026-10-17 (Saturday), there are 289 calendar days (0 years, 9 months, 16 days), consisting of 207 weekdays and 82 weekend days (207 net business days after subtracting 0 holidays).
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Formula & Mathematical Methodology: UTC-Safe Calendar Day & Weekday Enumeration

Total Days = UTC(End) − UTC(Start)86,400,000 + InclusiveOffset
TotalDays = (UTC(End) − UTC(Start)) / 86,400,000 + (Inclusive ? 1 : 0)
  • UTC(Date): Epoch milliseconds at 00:00:00 UTC for the calendar date
  • Weekdays: Count of days falling on Monday through Friday

Rounding: Exact integer day counting using UTC midnight timestamps to prevent Daylight Saving Time 23-hour/25-hour day errors.

Worked Example: Interval from 2026-01-01 to 2026-10-17 (Exclusive)

Find total days and business days from January 1, 2026 to October 17, 2026.

  1. Calendar span: 0 years, 9 months, 16 days.
  2. Total calendar days = 289 days (41 weeks, 2 days).
  3. Breakdown: 207 weekdays (Monday–Friday) and 82 weekend days.
Result: 289 calendar days (207 working days and 82 weekend days).

Frequently Asked Questions

Why do some naive JavaScript calculators lose a day in March or November?

Local browser `Date` objects shift by ±1 hour across Daylight Saving Time transitions. CalculatorGraph maps dates to UTC calendar coordinates so every calendar day is exactly 86,400,000 ms.

Dates & Time · Calendar Intervals & Working Days

Date Difference & Business Days Calculator: inputs, method, and how to read the result

Calculate total days, years/months/days, weekdays vs. weekends, and net working days between two calendar dates.

Choose inputs for the case you are checking

The defaults are illustrative. Replace them with values for your case and keep the units shown beside each field.

  • Start Date: Beginning date (YYYY-MM-DD).
  • End Date: Ending date (YYYY-MM-DD).
  • Include End Date (+1 Day)?: Whether both boundary dates count as full days.
  • Public Holidays During Period: Optional number of weekday public holidays to subtract from working days.

What the calculation includes

With the default values shown, Exact Calendar Duration is 0y 9m 16d (289 days). The calculation follows UTC-Safe Calendar Day & Weekday Enumeration; the formula and variable definitions above show how the inputs combine.

One-input check: With the other defaults held constant, changing Start Date from 2026-01-01 to 2025-12-31 changes Exact Calendar Duration from 0y 9m 16d (289 days) to 0y 9m 16d (290 days). This is a comparison inside the calculator's stated model, not a prediction.

Where to use caution

  • Standard workweek is Monday through Friday; Saturday and Sunday are counted as weekend days.
  • Holiday count is user-entered because statutory holiday calendars vary by country, state, and employer.

Scope: Global (Gregorian Calendar) Check the assumptions and limitations against your situation before relying on the estimate.

More in Dates & Time: Age Calculator, Freelance Pricing & Hourly Rate Calculator.