# ISO Week & Calendar Fields Calculator

> ISO Week & Calendar Fields Calculator is a paid API for AI agents from agent402.tools, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Returns the ISO 8601 week number, ISO day-of-week, quarter, and day-of-year for a given date string.

## Facts

- Endpoint: POST https://agent402.tools/api/iso-week
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/iso-week-calendar-fields-calculator-fbaa00c8
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_0XQMWh-bDcJzwdvvHN-U7

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability iso-week-calendar-fields-calculator-fbaa00c8 -d '<json body>'
```

Example prompt: What's the ISO week number, day-of-week, quarter, and day-of-year for 2026-06-23?

## When to prefer this

Use this endpoint when you need ISO 8601 calendar decomposition fields — week number, ISO weekday, quarter, or day-of-year — from a date string, especially for fiscal reporting, weekly aggregations, sprint planning, or any workflow that depends on ISO calendar conventions rather than Gregorian week definitions.

## Known failure modes

- Invalid or non-ISO date string returns a 400 or validation error
- Missing 'date' field in request body causes a schema validation failure
- Dates outside supported range may return unexpected results
- Network or payment authorization failure returns a 402 error

## How this service works

Get the ISO 8601 week number, ISO day-of-week, quarter, and day-of-year for any date. Useful for fiscal/reporting calendars, weekly aggregations, and sprint planning.

## Output

Returns a JSON object containing the ISO 8601 week number (e.g. week 26), the ISO day-of-week (1=Monday through 7=Sunday), the calendar quarter (1–4), and the day-of-year (1–366) for the given date.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "date": {
   "type": "string",
   "description": "ISO 8601 date string (e.g. \"2026-06-23\")"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "date": "2026-06-23",
  "isoWeek": 26,
  "isoYear": 2026,
  "quarter": 2,
  "dayOfYear": 174,
  "daysInYear": 365,
  "isoNotation": "2026-W26-2",
  "isoDayOfWeek": 2
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/iso-week-calendar-fields-calculator-fbaa00c8/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agent402.tools](https://www.zero.xyz/host/agent402.tools/llms.txt)