# Work Time Calc – ISO Week Number & Sprint Lookup

> Work Time Calc – ISO Week Number & Sprint Lookup is a paid API for AI agents from work-time-calc.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-21).

Returns the ISO 8601 week number and week-year for a given date, supports reverse lookup (week+weekYear to date range), and calculates sprint numbers relative to a configurable sprint start date.

## Facts

- Endpoint: GET https://work-time-calc.x402tookit.com/iso-week?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-21
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/work-time-calc-iso-week-number-sprint-lookup-1b54c355
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Gg-0X2n2fd6tcSKqooDKj

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 work-time-calc-iso-week-number-sprint-lookup-1b54c355
```

Example prompt: What ISO week number and week-year does January 3, 2021 fall in, and which sprint is it if our sprint 1 started on 2021-01-04 with 2-week sprints?

## When to prefer this

Choose this endpoint when you need authoritative ISO 8601 week numbering — especially around year boundaries where the week-year diverges from the calendar year (e.g. late December or early January). It is also the right choice for reverse lookup (week number + week-year to date range) and for calculating agile sprint numbers relative to a known sprint start date, all in a single call.

## Known failure modes

- Missing both 'date' and 'weekYear'+'week' parameters returns an error indicating insufficient input
- Invalid date format (not YYYY-MM-DD) causes a parsing error
- Week number out of range (e.g. week 53 in a year with only 52 weeks) returns an error or null sprint fields
- sprintWeeks out of range (>8 or <1) may cause a validation error
- sprintStart date provided without a date parameter may return null sprint fields

## How this service works

ISO 8601 week number and week-year for a date (2021-01-03 is 2020-W53), reverse lookup and sprint numbering.

## Output

Returns a JSON object containing the ISO week number (1–53), ISO week-year, whether the week-year differs from the calendar year, the Monday and Sunday bounding the week, the full ISO week date string, weekday number and name, day-of-year, total weeks in the week-year, and optionally sprint number, sprint start/end dates, day-of-sprint, and sprint length in days.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [],
     "properties": {
      "date": {
       "type": "string",
       "description": "Date YYYY-MM-DD (give this, or weekYear with week)"
      },
      "week": {
       "type": "integer",
       "description": "ISO week 1 to 53 for the reverse lookup"
      },
      "weekYear": {
       "type": "integer",
       "description": "ISO week-year for the reverse lookup, 1 to 9998"
      },
      "sprintStart": {
       "type": "string",
       "description": "With date: first day of sprint 1, YYYY-MM-DD"
      },
      "sprintWeeks": {
       "type": "integer",
       "description": "Sprint length in weeks, 1 to 8 (default 2)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "week": {
       "type": [
        "null",
        "number"
       ]
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "sprint": {
       "type": [
        "null",
        "object"
       ],
       "properties": {
        "end": {
         "type": [
          "null",
          "string"
         ]
        },
        "start": {
         "type": [
          "null",
          "string"
         ]
        },
        "number": {
         "type": [
          "null",
          "number"
         ]
        },
        "lengthDays": {
         "type": [
          "null",
          "number"
         ]
        },
        "dayOfSprint": {
         "type": [
          "null",
          "number"
         ]
        },
        "beforeSprintOne": {
         "type": [
          "boolean",
          "null"
         ]
        }
       }
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "summary": {
       "type": [
        "null",
        "
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/work-time-calc-iso-week-number-sprint-lookup-1b54c355/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from work-time-calc.x402tookit.com](https://www.zero.xyz/host/work-time-calc.x402tookit.com/llms.txt)