{"ok":true,"result":{"slug":"week-number-calculator","name":"Week Number Calculator","summary":"ISO 8601 week number, ISO week date, day of year and quarter for a date, or the Monday–Sunday dates of a given ISO week.","description":"Find the ISO 8601 week number of any date, plus day of year, days left, quarter and leap year, or look up the Monday-to-Sunday dates of any week.","method":"POST","endpoint":"/api/v1/tools/week-number-calculator","plan":"free","mcpName":"week_number_calculator","input":{"type":"object","additionalProperties":false,"properties":{"date":{"type":"string","description":"A date as YYYY-MM-DD to get its ISO week. Give this, or year and week.","maxLength":10},"year":{"type":"integer","description":"ISO week-numbering year, to get the dates of a week (with week).","minimum":1,"maximum":9999},"week":{"type":"integer","description":"ISO week number 1 to 52 (or 53 in long years), with year.","minimum":1,"maximum":53}}},"example":{"date":"2026-10-20"},"randomOutput":false,"network":false,"docs":"https://pithlab.com/developers/tools/week-number-calculator","page":"https://pithlab.com/tools/week-number-calculator"}}