Business Day Calculator

2026-01-05 to 2026-01-12 contains 5 business day(s), excluding Saturday and Sunday and the listed holidays.

How it works

• Parsed both dates as UTC calendar dates.
• Walked each day from the start up to (but not including) the end, and counted the days that are neither weekend nor holiday.
• Reported the business-day count, the calendar-day span, and what was skipped.

• The end date is exclusive in count mode; counting is symmetric when the end is earlier.

Methodology

1. Parse the start, end and holiday dates as UTC calendar dates and build the set of ISO weekdays that form the weekend (default Saturday and Sunday).
2. A business day is a calendar day whose weekday is not a weekend day and whose date is not in the holiday list.
3. Count every business day in the half-open interval, or step one calendar day at a time for an offset while decrementing the remaining count only on business days.

Time model

• Time source: an explicit reference supplied by the visitor.
• Timezone: Dates are timezone-less calendar dates interpreted in UTC; the visitor's timezone does not shift them.
• Locale: ISO-8601 dates only; no locale-specific ordering or month names are used.
• Daylight saving: Whole-calendar-day arithmetic is DST-independent; daylight-saving transitions never change a day count.
• Reference date: A start date is required; an end date or a signed day count is supplied explicitly.

Usage

1. Enter the start date as YYYY-MM-DD.
2. Enter an end date to count business days, or a signed count to add business days.
3. Optionally list holidays and change the weekend days, then read the result.

Examples

These are examples, not current values: they use fixed inputs, while the interactive tool computes live results in your browser.

Count across a weekend

{
  "start": "2026-01-05",
  "end": "2026-01-12"
}

Count across a weekend and a holiday

{
  "start": "2026-01-05",
  "end": "2026-01-12",
  "holidays": [
    "2026-01-08"
  ]
}

Add ten business days

{
  "start": "2026-01-05",
  "addDays": 10,
  "holidays": [
    "2026-01-19"
  ]
}

Subtract two business days across a weekend

{
  "start": "2026-01-05",
  "addDays": -2
}

Limitations

Exclusive versus inclusive counting

If work starts on a Monday and finishes on the following Monday, the elapsed working days are the five days Monday to Friday; counting up to but not including the second Monday gives that number directly.