{"success":true,"version":"v1","request":{"tool":"get_calculator_schema","calculator_id":"golf-handicap"},"result":{"entity_type":"calculator","id":"golf-handicap","calculator_id":"golf-handicap","canonical_url":"https://tttkmbb.com/fitness/golf-handicap","name":"Golf Handicap Calculator","title":"Golf Handicap Index Calculator – World Handicap System Score Differentials and Course Handicap","category":"fitness","category_name":"Sports & Fitness","tool_name":"calculate_golf_handicap_index","featured_mcp_tool":false,"description":"Computes a golf Handicap Index under the World Handicap System (USGA/R&A) from 3–20 adjusted gross scores: each score differential = (score − course rating) × 113 / slope rating, the index is the average of the lowest differentials selected by the WHS table (with −2.0 / −1.0 adjustments for 3, 4 and 6 scores), and optionally the Course Handicap for a given par.","use_when":"You have a golfer's recent 18-hole adjusted gross scores with the course rating and slope rating and need the WHS Handicap Index, the score differentials or the Course Handicap for a set of tees.","do_not_use_when":"You need an official handicap (only a club or association system with playing-conditions and cap adjustments issues one), the scores are from 9-hole rounds, or the rounds were played on tees with different ratings (compute each differential with its own rating first).","inputs":[{"name":"scores","label":"Adjusted gross scores","type":"number_list","required":true,"description":"3–20 adjusted gross scores (18 holes, net double bogey applied), most recent last; only the most recent 20 rounds count under WHS.","example":[88,92,85,90,95]},{"name":"course_rating","label":"Course rating","type":"number","required":false,"default":72,"min":40,"max":90,"description":"USGA/R&A course rating of the tees played (assumed the same for all scores).","example":72},{"name":"slope_rating","label":"Slope rating","type":"integer","required":false,"default":113,"min":55,"max":155,"description":"Slope rating of the tees played (55–155; 113 is standard difficulty).","example":130},{"name":"par","label":"Par","type":"integer","required":false,"min":54,"max":80,"description":"Par of the tees played; when given, the Course Handicap is also reported.","example":72}],"outputs":[{"name":"handicap_index","label":"Handicap Index","type":"number","decimals":1,"description":"Average of the lowest score differentials per the WHS table plus the adjustment, rounded to 0.1 and capped at 54.0; a negative value is a 'plus' handicap (e.g. −2.0 = +2.0)."},{"name":"differentials","label":"Score differentials","type":"number_list","decimals":1,"description":"(score − course_rating) × 113 / slope_rating for each score, in input order, each rounded to 0.1."},{"name":"differentials_used","label":"Differentials used","type":"integer","decimals":4,"description":"How many of the lowest differentials are averaged (1–8, depending on the number of scores)."},{"name":"adjustment","label":"Adjustment","type":"number","decimals":1,"description":"WHS adjustment added to the average: −2.0 with 3 scores, −1.0 with 4 or 6 scores, otherwise 0."},{"name":"course_handicap","label":"Course Handicap","type":"integer","decimals":4,"description":"handicap_index × slope_rating / 113 + (course_rating − par), rounded to the nearest whole number (only when par is given)."},{"name":"method_text","label":"Method","type":"string","decimals":4,"description":"Which WHS table row was applied and which differentials were averaged."}],"input_schema":{"type":"object","properties":{"scores":{"description":"3–20 adjusted gross scores (18 holes, net double bogey applied), most recent last; only the most recent 20 rounds count under WHS.","type":"array","items":{"type":"number"},"minItems":3,"examples":[[88,92,85,90,95]]},"course_rating":{"description":"USGA/R&A course rating of the tees played (assumed the same for all scores).","type":"number","minimum":40,"maximum":90,"default":72,"examples":[72]},"slope_rating":{"description":"Slope rating of the tees played (55–155; 113 is standard difficulty).","type":"integer","minimum":55,"maximum":155,"default":113,"examples":[130]},"par":{"description":"Par of the tees played; when given, the Course Handicap is also reported.","type":"integer","minimum":54,"maximum":80,"examples":[72]}},"additionalProperties":false,"required":["scores"]},"output_schema":{"type":"object","properties":{"handicap_index":{"description":"Average of the lowest score differentials per the WHS table plus the adjustment, rounded to 0.1 and capped at 54.0; a negative value is a 'plus' handicap (e.g. −2.0 = +2.0).","type":"number"},"differentials":{"description":"(score − course_rating) × 113 / slope_rating for each score, in input order, each rounded to 0.1.","type":"array","items":{"type":"number"}},"differentials_used":{"description":"How many of the lowest differentials are averaged (1–8, depending on the number of scores).","type":"integer"},"adjustment":{"description":"WHS adjustment added to the average: −2.0 with 3 scores, −1.0 with 4 or 6 scores, otherwise 0.","type":"number"},"course_handicap":{"description":"handicap_index × slope_rating / 113 + (course_rating − par), rounded to the nearest whole number (only when par is given).","type":"integer"},"method_text":{"description":"Which WHS table row was applied and which differentials were averaged.","type":"string"}}},"formula":"differential_i = round0.1((score_i − course_rating) × 113 / slope_rating); handicap_index = min(54.0, round0.1(mean(lowest n differentials) + adjustment)) with (number of scores → n, adjustment): 3 → 1, −2.0; 4 → 1, −1.0; 5 → 1, 0; 6 → 2, −1.0; 7–8 → 2, 0; 9–11 → 3; 12–14 → 4; 15–16 → 5; 17–18 → 6; 19 → 7; 20 → 8; course_handicap = round(handicap_index × slope_rating / 113 + course_rating − par)","method":"World Handicap System, Rules of Handicapping Rule 5.2 (score differentials and Handicap Index calculation) and Rule 6.1 (Course Handicap). The playing conditions calculation (PCC), soft and hard caps, exceptional-score reductions and 9-hole score combination are not applied, and all scores are assumed to come from tees with the given rating and slope. Informational, not an official handicap.","sources":[{"name":"USGA – Handicapping: Rules of Handicapping under the World Handicap System (score differential, Handicap Index, Course Handicap)","url":"https://www.usga.org/handicapping.html","type":"standard","retrieved_at":"2026-09-24"},{"name":"The R&A – World Handicap System","url":"https://www.randa.org/","type":"standard","retrieved_at":"2026-09-24"},{"name":"Wikipedia – Handicap (golf): World Handicap System calculation","url":"https://en.wikipedia.org/wiki/Handicap_(golf)","type":"reference","retrieved_at":"2026-09-24"}],"freshness":{"type":"static","max_age_seconds":null,"note":"Deterministic formula with fixed constants; results never go stale. Inputs supplied by the caller determine the output."},"examples":[{"name":"5 scores, CR 72, slope 130, par 72","inputs":{"scores":[88,92,85,90,95],"course_rating":72,"slope_rating":130,"par":72},"expected":{"differentials":[13.9,17.4,11.3,15.6,20],"handicap_index":11.3,"differentials_used":1,"adjustment":0,"course_handicap":13},"url":"https://tttkmbb.com/api/v1/calculate/golf-handicap?scores=88%2C92%2C85%2C90%2C95&course_rating=72&slope_rating=130&par=72"},{"name":"6 scores, CR 71.5, slope 125, par 72","inputs":{"scores":[95,90,88,92,86,91],"course_rating":71.5,"slope_rating":125,"par":72},"expected":{"differentials":[21.2,16.7,14.9,18.5,13.1,17.6],"handicap_index":13,"differentials_used":2,"adjustment":-1,"course_handicap":14},"url":"https://tttkmbb.com/api/v1/calculate/golf-handicap?scores=95%2C90%2C88%2C92%2C86%2C91&course_rating=71.5&slope_rating=125&par=72"}],"faq":[{"q":"Why does this differ from my club's Handicap Index?","a":"Official systems apply a playing conditions calculation (−1 to +3) to each round, cap upward movement and use every round's own course rating and slope; this calculator assumes one rating for all scores and PCC 0."},{"q":"What is an adjusted gross score?","a":"The gross score after limiting each hole to net double bogey (par + 2 + any handicap strokes received on that hole), the WHS maximum hole score for handicap purposes."},{"q":"Which Course Handicap formula is used?","a":"The WHS formula Handicap Index × (slope ÷ 113) + (course rating − par), rounded to a whole number. Before the 2024 revision some jurisdictions (e.g. Great Britain and Ireland) omitted the (course rating − par) term."}],"tags":["golf handicap","handicap index","world handicap system","score differential","course handicap","slope rating"],"related":[{"calculator_id":"steps-to-distance","reason":"Distance walked during an 18-hole round from a step count."},{"calculator_id":"calories-burned","reason":"Energy cost of walking the course (MET table)."}],"links":{"html":"https://tttkmbb.com/fitness/golf-handicap","markdown":"https://tttkmbb.com/fitness/golf-handicap.md","json":"https://tttkmbb.com/fitness/golf-handicap.json","api":"https://tttkmbb.com/api/v1/calculate/golf-handicap","schema":"https://tttkmbb.com/api/v1/calculators/golf-handicap","openapi":"https://tttkmbb.com/openapi.json","mcp":"https://tttkmbb.com/mcp"},"version":"v1","updated_at":"2026-09-24"},"timestamp":"2026-09-24T03:48:17Z","next_actions":[{"tool":"run_calculator","calculator_id":"golf-handicap","reason":"Run Golf Handicap Calculator with the inputs above."}],"links":{"markdown":"https://tttkmbb.com/fitness/golf-handicap.md"}}