ISO date business days count

iso-date-business-days-count · version 1.0.0 · Dates & times (UTC, ISO 8601) · free, no key needed

Count the business days in an inclusive date range, skipping caller-supplied weekend weekdays and holidays.

Use when you need to: iso date business days count · count working days between dates · business days between two dates.

Supported

iso date business days count
count working days between dates
business days between two dates

Not supported

built-in national holiday calendars
timezones
half-day rules
signed/negative ranges

Behavior

start and end are strict YYYY-MM-DD calendar dates with year 0001-9999. start must not be after end.
end minus start must not exceed 366000 days.
weekend_days is an array of ISO weekday integers 1-7, unique, at most 6 entries. holidays is an array of unique YYYY-MM-DD dates, at most 366 entries.
business_days counts every date d with start <= d <= end whose ISO weekday is not in weekend_days and that is not listed in holidays.

Input

start (string, required): min length 10; max length 10; pattern ^\d{4}-\d{2}-\d{2}$
end (string, required): min length 10; max length 10; pattern ^\d{4}-\d{2}-\d{2}$
weekend_days (array of integer, required): max items 6; each min 1; each max 7
holidays (array of string, required): max items 366; each min length 10; each max length 10

Output

business_days (integer, required): min 0

Limits

year min: 1
year max: 9999
max range days: 366000
max weekend days: 6
max holidays: 366

Example

Request input:

{
  "start": "2026-09-14",
  "end": "2026-09-20",
  "weekend_days": [
    6,
    7
  ],
  "holidays": []
}

Response:

{
  "result": {
    "business_days": 5
  }
}

How to call it

MCP

Connect https://computefirst.net/mcp (setup), then call execute with:

{
  "id": "iso-date-business-days-count",
  "version": "1.0.0",
  "input": {
    "start": "2026-09-14",
    "end": "2026-09-20",
    "weekend_days": [
      6,
      7
    ],
    "holidays": []
  }
}

HTTP (no key)

curl -X POST https://computefirst.net/v1/tools/iso-date-business-days-count/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"start":"2026-09-14","end":"2026-09-20","weekend_days":[6,7],"holidays":[]}'

The machine-readable contract is at /v1/tools/iso-date-business-days-count/versions/1.0.0.

CLI

node cli.mjs run iso-date-business-days-count 1.0.0 --input input.json --base-url https://computefirst.net

Get the client at /clients/cli/.

ISO date age: Compute the calendar-aware elapsed years, months, and days between a birth date and an as-of date.
ISO date business day add: Add a signed count of business days to a date, skipping caller-supplied weekend weekdays and holidays.
ISO date difference: Whole days from start to end as a canonical integer string (end - start).
ISO date range intersect: Compute the intersection of two inclusive [start, end] date ranges.
ISO date range list: Enumerate the dates in an inclusive [start, end] range stepped by a whole number of days.
ISO date weekday occurrences in range: List every date within an inclusive date range that falls on a given ISO weekday.