ISO date range intersect

iso-date-range-intersect · version 1.0.0 · Dates & times (UTC, ISO 8601) · free, no key needed

Compute the intersection of two inclusive [start, end] date ranges.

Use when you need to: iso date range intersect · overlap of two date ranges · common days between date ranges.

Supported

• iso date range intersect
• overlap of two date ranges
• common days between date ranges

Not supported

• open ranges
• timezones
• datetime ranges
• multi-range intersection

Behavior

• a and b are each an inclusive [start, end] YYYY-MM-DD date range with year 0001-9999; start must not be after end in either.
• intersection is {start, end} covering the days common to both ranges (max(a.start,b.start) to min(a.end,b.end)) when they overlap, or null when they do not.

Input

• a (object, required)
• b (object, required)

Output

• intersection (null or object, required)

Limits

• year min: 1
• year max: 9999

Example

Request input:

{
  "a": {
    "start": "2026-01-01",
    "end": "2026-01-10"
  },
  "b": {
    "start": "2026-01-05",
    "end": "2026-01-20"
  }
}

Response:

{
  "result": {
    "intersection": {
      "start": "2026-01-05",
      "end": "2026-01-10"
    }
  }
}

How to call it

MCP

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

{
  "id": "iso-date-range-intersect",
  "version": "1.0.0",
  "input": {
    "a": {
      "start": "2026-01-01",
      "end": "2026-01-10"
    },
    "b": {
      "start": "2026-01-05",
      "end": "2026-01-20"
    }
  }
}

HTTP (no key)

curl -X POST https://computefirst.net/v1/tools/iso-date-range-intersect/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"a":{"start":"2026-01-01","end":"2026-01-10"},"b":{"start":"2026-01-05","end":"2026-01-20"}}'

The machine-readable contract is at /v1/tools/iso-date-range-intersect/versions/1.0.0.

CLI

node cli.mjs run iso-date-range-intersect 1.0.0 --input input.json --base-url https://computefirst.net

Get the client at /clients/cli/.

Related tools

• ISO date range overlap: Test whether two inclusive [start, end] date ranges share at least one day.
• ISO date business days count: Count the business days in an inclusive date range, skipping caller-supplied weekend weekdays and holidays.
• 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.
• ISO date age: Compute the calendar-aware elapsed years, months, and days between a birth date and an as-of date.
• ISO date difference: Whole days from start to end as a canonical integer string (end - start).