{"success":true,"version":"v1","request":{"tool":"get_calculator_schema","calculator_id":"anniversary"},"result":{"entity_type":"calculator","id":"anniversary","calculator_id":"anniversary","canonical_url":"https://tttkmbb.com/time/anniversary","name":"Anniversary Calculator","title":"Anniversary Calculator – Years Together, Next Anniversary Countdown and Traditional Gift","category":"time","category_name":"Time & Geography","tool_name":"calculate_anniversary","featured_mcp_tool":false,"description":"Counts completed years, months and days since a start date (wedding, job, founding), finds the next anniversary date and the days until it, and names the traditional anniversary gift material for that year.","use_when":"You want to know which anniversary is coming up, how many days remain until it, or the traditional gift for a given anniversary year.","do_not_use_when":"You need someone's age (use age) or a general date difference with business days (use date-difference).","inputs":[{"name":"start_date","label":"Start date","type":"date","required":true,"description":"Date of the original event (YYYY-MM-DD), e.g. the wedding date.","example":"2015-06-20"},{"name":"as_of_date","label":"As of","type":"date","required":false,"default":"today","description":"Reference date; defaults to the current UTC date.","example":"2026-09-23"}],"outputs":[{"name":"years_completed","label":"Years completed","type":"integer","unit":"years","decimals":4,"description":"Full years elapsed on as_of_date."},{"name":"elapsed_text","label":"Elapsed","type":"string","decimals":4,"description":"Years, months and days since start_date."},{"name":"days_since_start","label":"Days since start","type":"integer","unit":"days","decimals":4,"description":"as_of_date − start_date."},{"name":"next_anniversary_date","label":"Next anniversary","type":"date","decimals":4,"description":"First anniversary date on or after as_of_date (29 February → 1 March in common years)."},{"name":"next_anniversary_number","label":"Anniversary number","type":"integer","decimals":4,"description":"Ordinal of the next anniversary (e.g. 12 for the 12th)."},{"name":"next_anniversary_weekday","label":"Weekday","type":"string","decimals":4,"description":"Day of the week of the next anniversary."},{"name":"days_until_next_anniversary","label":"Days until next anniversary","type":"integer","unit":"days","decimals":4,"description":"0 when as_of_date is the anniversary itself."},{"name":"is_anniversary_today","label":"Anniversary today","type":"boolean","decimals":4,"description":"true when as_of_date is an anniversary of start_date."},{"name":"traditional_gift","label":"Traditional gift","type":"string","decimals":4,"description":"Traditional gift material for the next anniversary year (years 1–15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 70)."}],"input_schema":{"type":"object","properties":{"start_date":{"description":"Date of the original event (YYYY-MM-DD), e.g. the wedding date.","type":"string","format":"date","examples":["2015-06-20"]},"as_of_date":{"description":"Reference date; defaults to the current UTC date.","type":"string","format":"date","default":"today","examples":["2026-09-23"]}},"additionalProperties":false,"required":["start_date"]},"output_schema":{"type":"object","properties":{"years_completed":{"description":"Full years elapsed on as_of_date. Unit: years.","type":"integer","x-unit":"years"},"elapsed_text":{"description":"Years, months and days since start_date.","type":"string"},"days_since_start":{"description":"as_of_date − start_date. Unit: days.","type":"integer","x-unit":"days"},"next_anniversary_date":{"description":"First anniversary date on or after as_of_date (29 February → 1 March in common years).","type":"string","format":"date"},"next_anniversary_number":{"description":"Ordinal of the next anniversary (e.g. 12 for the 12th).","type":"integer"},"next_anniversary_weekday":{"description":"Day of the week of the next anniversary.","type":"string"},"days_until_next_anniversary":{"description":"0 when as_of_date is the anniversary itself. Unit: days.","type":"integer","x-unit":"days"},"is_anniversary_today":{"description":"true when as_of_date is an anniversary of start_date.","type":"boolean"},"traditional_gift":{"description":"Traditional gift material for the next anniversary year (years 1–15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 70).","type":"string"}}},"formula":"years_completed = calendar years from start_date to as_of_date; next_anniversary = first (month, day) of start_date on or after as_of_date; days_until = next_anniversary − as_of_date","method":"Gregorian calendar arithmetic in UTC. Gift materials follow the common US/UK traditional list (paper, cotton, leather … silver at 25, gold at 50, diamond at 60); years without a traditional material return a note instead.","sources":[{"name":"Wedding anniversary – traditional gift lists (Wikipedia)","url":"https://en.wikipedia.org/wiki/Wedding_anniversary","type":"reference","retrieved_at":"2026-09-24"},{"name":"Gregorian calendar – leap-year rule and month lengths (Wikipedia)","url":"https://en.wikipedia.org/wiki/Gregorian_calendar","type":"reference","retrieved_at":"2026-09-24"}],"freshness":{"type":"daily","max_age_seconds":86400,"note":"Depends on the current date unless the date is supplied."},"examples":[{"name":"Wedding 2015-06-20, as of 2026-09-23","inputs":{"start_date":"2015-06-20","as_of_date":"2026-09-23"},"expected":{"years_completed":11,"elapsed_text":"11 years 3 months 3 days","days_since_start":4113,"next_anniversary_date":"2027-06-20","next_anniversary_number":12,"next_anniversary_weekday":"Sunday","days_until_next_anniversary":270,"is_anniversary_today":false,"traditional_gift":"Silk"},"url":"https://tttkmbb.com/api/v1/calculate/anniversary?start_date=2015-06-20&as_of_date=2026-09-23"},{"name":"Silver wedding: 1999-02-14 as of 2024-02-14","inputs":{"start_date":"1999-02-14","as_of_date":"2024-02-14"},"expected":{"years_completed":25,"days_since_start":9131,"next_anniversary_date":"2024-02-14","next_anniversary_number":25,"days_until_next_anniversary":0,"is_anniversary_today":true,"traditional_gift":"Silver"},"url":"https://tttkmbb.com/api/v1/calculate/anniversary?start_date=1999-02-14&as_of_date=2024-02-14"}],"faq":[{"q":"Which anniversary does the gift refer to?","a":"The next one: on 2026-09-23 a couple married on 2015-06-20 has completed 11 years, so the upcoming 12th anniversary (silk) is reported. On the anniversary day itself that day's number is used."},{"q":"Are modern gift lists included?","a":"No; only the traditional materials. Modern lists (clocks, china, crystal, appliances…) vary by country and retailer."}],"tags":["anniversary calculator","wedding anniversary","years together","anniversary gift by year","days until anniversary"],"related":[{"calculator_id":"age","reason":"The same calculation for a person's birthday."},{"calculator_id":"days-until","reason":"Countdown to any date."},{"calculator_id":"date-difference","reason":"Exact difference between two dates including business days."}],"links":{"html":"https://tttkmbb.com/time/anniversary","markdown":"https://tttkmbb.com/time/anniversary.md","json":"https://tttkmbb.com/time/anniversary.json","api":"https://tttkmbb.com/api/v1/calculate/anniversary","schema":"https://tttkmbb.com/api/v1/calculators/anniversary","openapi":"https://tttkmbb.com/openapi.json","mcp":"https://tttkmbb.com/mcp"},"version":"v1","updated_at":"2026-09-24"},"timestamp":"2026-09-24T01:57:58Z"}