{"uid":"cap_oUk6NcOLW3sp4dghsuoHY","slug":"magent-rfm-calculator-woolcott-2018-3a533d1c","name":"magent RFM Calculator (Woolcott 2018)","description":"Relative fat mass (RFM) from height, waist, and sex (Woolcott 2018). Height and waist in meters in the paper; magent accepts height_cm or height_in and waist_cm. Deterministic published arithmetic with citation. Not a medical device, not a body-fat diagnosis, and not later obesity cutoffs. magent does not measure the patient.","url":"https://api.magentlab.com/api/calc/rfm","method":"GET","headers":{},"bodySchema":{"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","HEAD","DELETE"],"type":"string"},"headers":{"type":"object","additionalProperties":{"type":"string"}},"queryParams":{"type":"object","required":["waist_cm","sex"],"properties":{"sex":{"enum":["female","male"],"type":"string","description":"Sex used by Woolcott 2018 (0 male, 1 female in the RFM equation)."},"waist_cm":{"type":"number","description":"Waist circumference in centimeters (40-200). Converted to meters for RFM."},"height_cm":{"type":"number","description":"Height in centimeters. Provide height_cm or height_in."},"height_in":{"type":"number","description":"Height in inches. Converted as cm = in * 2.54."}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.005","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.005/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.005","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.005","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_7xkuyGe8RICRvhAIwrhdH","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.005","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Calculates Relative Fat Mass (RFM) from height, waist circumference, and sex using the Woolcott 2018 published formula","exampleAgentPrompt":"Calculate the relative fat mass using the Woolcott 2018 RFM formula for a male patient who is 178 cm tall with a waist circumference of 92 cm.","exampleUseCases":[{"title":"Clinical anthropometric screening tool","prompt":"Can you compute the Woolcott RFM score for a female patient who is 64 inches tall with a waist of 82 cm?"},{"title":"Population health research pipeline","prompt":"I'm processing a cohort dataset and need to compute RFM values — run the Woolcott 2018 formula for a male with height 182 cm and waist 95 cm."},{"title":"Fitness app body composition feature","prompt":"What is the relative fat mass for a male user who is 170 cm tall and has a waist of 85 cm? Use the published RFM arithmetic."}],"resultDescription":"Returns a numeric Relative Fat Mass (RFM) value computed from the Woolcott 2018 formula (64 − 20 × height/waist ± sex constant), representing an estimate of body fat percentage derived purely from height, waist, and sex inputs. No diagnosis or clinical classification is included.","failureModes":["Missing required waist_cm or sex parameter returns an error","Waist value outside the accepted range (40–200 cm) may produce an error or unexpected result","Providing both height_cm and height_in may cause ambiguity; only one should be supplied","Invalid sex enum value (not 'male' or 'female') returns a validation error","Omitting height entirely results in missing data for the formula"],"whenToPreferThis":"Choose this endpoint when you need a fast, deterministic, citation-backed anthropometric body fat estimate using only height and waist measurements — particularly when DEXA or bioimpedance data are unavailable. It implements the specific Woolcott 2018 formula with unit-conversion support (inches to cm), making it ideal for clinical decision support pipelines, health app integrations, or research workflows that require reproducible arithmetic without ambiguity. Prefer over BMI-based endpoints when waist circumference is available and a body fat proxy is needed.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-16T01:03:37.128Z","isFirstParty":false}