{"success":true,"version":"v1","request":{"tool":"get_calculator_schema","calculator_id":"age"},"result":{"entity_type":"calculator","id":"age","calculator_id":"age","canonical_url":"https://tttkmbb.com/everyday/age","name":"Age Calculator","title":"Age Calculator – Exact Age in Years, Months and Days from Date of Birth","category":"everyday","category_name":"Everyday Life","tool_name":"calculate_age","featured_mcp_tool":true,"description":"Computes the exact age on a given date as years, months and days by Gregorian calendar arithmetic, plus total days and weeks, the weekday of birth, and the date of and days until the next birthday.","use_when":"You need someone's exact age on a date, the total number of days lived, the weekday they were born on, or how many days remain until their next birthday.","do_not_use_when":"You need the difference between two arbitrary dates with a business-day count (use date-difference) or a countdown to an event (use days-until).","inputs":[{"name":"birth_date","label":"Date of birth","type":"date","required":true,"description":"Date of birth (ISO 8601, YYYY-MM-DD).","example":"1990-05-17"},{"name":"as_of_date","label":"Age as of","type":"date","required":false,"default":"today","description":"Date on which to evaluate the age; defaults to the current UTC date.","example":"2026-09-23"}],"outputs":[{"name":"years","label":"Years","type":"integer","decimals":4,"description":"Completed years."},{"name":"months","label":"Months","type":"integer","decimals":4,"description":"Completed months beyond the years (0–11)."},{"name":"days","label":"Days","type":"integer","decimals":4,"description":"Days beyond the completed months."},{"name":"age_text","label":"Age","type":"string","decimals":4,"description":"Age written as years, months and days (zero parts omitted)."},{"name":"total_days","label":"Total days","type":"integer","unit":"days","decimals":4,"description":"Days from birth_date to as_of_date."},{"name":"total_weeks","label":"Total weeks","type":"number","unit":"weeks","decimals":1,"description":"total_days / 7."},{"name":"age_decimal_years","label":"Age (decimal)","type":"number","unit":"years","decimals":2,"description":"total_days / 365.2425 (mean Gregorian year)."},{"name":"next_birthday_date","label":"Next birthday","type":"date","decimals":4,"description":"First birthday anniversary on or after as_of_date (a 29 February birthday falls on 1 March in non-leap years)."},{"name":"days_until_next_birthday","label":"Days until next birthday","type":"integer","unit":"days","decimals":4,"description":"0 on the birthday itself."},{"name":"day_of_week_born","label":"Weekday of birth","type":"string","decimals":4,"description":"Day of the week of birth_date."}],"input_schema":{"type":"object","properties":{"birth_date":{"description":"Date of birth (ISO 8601, YYYY-MM-DD).","type":"string","format":"date","examples":["1990-05-17"]},"as_of_date":{"description":"Date on which to evaluate the age; defaults to the current UTC date.","type":"string","format":"date","default":"today","examples":["2026-09-23"]}},"additionalProperties":false,"required":["birth_date"]},"output_schema":{"type":"object","properties":{"years":{"description":"Completed years.","type":"integer"},"months":{"description":"Completed months beyond the years (0–11).","type":"integer"},"days":{"description":"Days beyond the completed months.","type":"integer"},"age_text":{"description":"Age written as years, months and days (zero parts omitted).","type":"string"},"total_days":{"description":"Days from birth_date to as_of_date. Unit: days.","type":"integer","x-unit":"days"},"total_weeks":{"description":"total_days / 7. Unit: weeks.","type":"number","x-unit":"weeks"},"age_decimal_years":{"description":"total_days / 365.2425 (mean Gregorian year). Unit: years.","type":"number","x-unit":"years"},"next_birthday_date":{"description":"First birthday anniversary on or after as_of_date (a 29 February birthday falls on 1 March in non-leap years).","type":"string","format":"date"},"days_until_next_birthday":{"description":"0 on the birthday itself. Unit: days.","type":"integer","x-unit":"days"},"day_of_week_born":{"description":"Day of the week of birth_date.","type":"string"}}},"formula":"years, months, days = calendar difference birth_date → as_of_date (when the day-of-month is smaller, days are borrowed from the month before as_of_date); total_days = as_of_date − birth_date; total_weeks = total_days / 7; age_decimal_years = total_days / 365.2425; next_birthday = first (month, day) of birth on or after as_of_date","method":"Uses the proleptic Gregorian calendar in UTC; no time zones or times of day are considered. A person born on 29 February is treated as having their birthday on 1 March in common years.","sources":[{"name":"Gregorian calendar – leap-year rule and month lengths (Wikipedia)","url":"https://en.wikipedia.org/wiki/Gregorian_calendar","type":"reference","retrieved_at":"2026-09-23"},{"name":"ISO 8601 – Date and time format (Wikipedia)","url":"https://en.wikipedia.org/wiki/ISO_8601","type":"reference","retrieved_at":"2026-09-23"}],"freshness":{"type":"daily","max_age_seconds":86400,"note":"Depends on the current date unless the date is supplied."},"examples":[{"name":"Born 1990-05-17, as of 2026-09-23","inputs":{"birth_date":"1990-05-17","as_of_date":"2026-09-23"},"expected":{"years":36,"months":4,"days":6,"age_text":"36 years 4 months 6 days","total_days":13278,"total_weeks":1896.9,"age_decimal_years":36.35,"next_birthday_date":"2027-05-17","days_until_next_birthday":236,"day_of_week_born":"Thursday"},"url":"https://tttkmbb.com/api/v1/calculate/age?birth_date=1990-05-17&as_of_date=2026-09-23"},{"name":"Born 1985-12-25, as of 2026-01-10","inputs":{"birth_date":"1985-12-25","as_of_date":"2026-01-10"},"expected":{"years":40,"months":0,"days":16,"age_text":"40 years 16 days","total_days":14626,"next_birthday_date":"2026-12-25","days_until_next_birthday":349,"day_of_week_born":"Wednesday"},"url":"https://tttkmbb.com/api/v1/calculate/age?birth_date=1985-12-25&as_of_date=2026-01-10"}],"faq":[{"q":"How are months counted when the day of the month does not fit?","a":"Whole months are counted first; the leftover days are borrowed from the month preceding as_of_date. Born 31 January, on 1 March the age is 1 month 1 day (February has 28 or 29 days)."},{"q":"What happens with a 29 February birthday?","a":"In common years the birthday is taken as 1 March, so days_until_next_birthday counts to 1 March; in leap years it counts to 29 February."}],"tags":["age","how old am I","age in days","birthday","date of birth"],"related":[{"calculator_id":"date-difference","reason":"Difference between any two dates, including business days."},{"calculator_id":"days-until","reason":"Countdown to any date, e.g. the next birthday."},{"calculator_id":"day-of-week","reason":"Weekday and ISO week of any date."}],"links":{"html":"https://tttkmbb.com/everyday/age","markdown":"https://tttkmbb.com/everyday/age.md","json":"https://tttkmbb.com/everyday/age.json","api":"https://tttkmbb.com/api/v1/calculate/age","schema":"https://tttkmbb.com/api/v1/calculators/age","openapi":"https://tttkmbb.com/openapi.json","mcp":"https://tttkmbb.com/mcp"},"version":"v1","updated_at":"2026-09-23"},"timestamp":"2026-09-23T23:23:14Z"}