FFMI Calculator
Calculate your fat-free mass index (FFMI) and adjusted FFMI from height, weight and body fat %.
제지방량 63.8kg 기준 — 키 보정 전 FFMI 20.82
상세 결과
결과 공유
참고 구간(비공식, Kouri et al. 1995 기준)
남성 기준 보정 FFMI 16 미만 평균 이하 · 16~18 평균 · 18~20 평균 이상 · 20~22 근육질 · 22~25 매우 근육질 · 25 이상은 자연적으로 도달하기 어려운 한계 근접(약물 사용 의심) 구간으로 통용됩니다. 이 구간은 남성 보디빌더 표본을 기준으로 하며, 여성의 공식 통용 구간은 확립되어 있지 않아 여성은 수치만 참고하세요. 체지방률 측정 오차에 따라 결과가 달라질 수 있어 진단·의학적 판단으로 사용할 수 없습니다.
Overview
Calculate your Fat-Free Mass Index (FFMI) and height-adjusted FFMI from height, weight, and body fat percentage. Unlike BMI, which only looks at total body weight, FFMI isolates lean mass (muscle, bone, water) to gauge muscularity, so it can distinguish a muscular physique from a fat-heavy one at the same body weight. The adjusted FFMI uses the formula published by Kouri et al. (1995) to correct for height differences.
Formula
Fat-Free Mass (FFM, kg) = weight × (1 − body fat% ÷ 100) FFMI = FFM ÷ height(m)² Adjusted FFMI = FFMI + 6.1 × (1.8 − height in m) (Kouri et al. 1995) Example) height 175 cm, weight 75 kg, body fat 15% FFM = 75 × 0.85 = 63.75 kg FFMI = 63.75 ÷ 1.75² = 63.75 ÷ 3.0625 = 20.82 Adjusted FFMI = 20.82 + 6.1×(1.8−1.75) = 20.82 + 0.305 = 21.12
How to Use
- 1Select your sex (the reference ranges are based on a male bodybuilder sample).
- 2Enter your height in cm (e.g., 175 cm).
- 3Enter your weight in kg (e.g., 75 kg).
- 4Enter your body fat percentage (e.g., 15%, from a caliper or bioimpedance scan).
- 5Fat-free mass, FFMI, and the height-adjusted FFMI are calculated automatically with a reference range.
Examples
Male, 175 cm, 75 kg, 15% body fat
A standard-build male maintaining 15% body fat.
Male, 180 cm, 90 kg, 20% body fat
A larger-framed male with a somewhat higher body fat percentage, exactly at the 1.8 m reference height.
Female, 165 cm, 60 kg, 25% body fat
For women, the male-derived reference ranges don't formally apply, so treat the numbers as informational only.
Background
FFMI was introduced in 1995 by psychiatrist Harrison Pope's research team to help distinguish anabolic steroid users from non-users (Kouri, Pope et al., 'Fat-free mass index in users and nonusers of anabolic-androgenic steroids', Clinical Journal of Sport Medicine, 1995). The study observed that natural (non-steroid-using) male bodybuilders rarely exceeded an adjusted FFMI of 25, which became a widely cited informal 'natural limit' benchmark. It is not an absolute diagnostic threshold — genetic outliers and body-fat measurement error can push the number above 25 naturally.
Tips
- ✔Body fat measurement methods (bioimpedance, calipers, DEXA) vary in accuracy, so tracking trends with the same method is more useful than a single reading.
- ✔Taller individuals tend to have a lower raw FFMI, so comparing adjusted FFMI is fairer across heights.
- ✔An adjusted FFMI above 25 does not automatically imply drug use — rare natural outliers exist; treat the range as informational.
- ✔At the same body weight, lower body fat yields a higher FFMI, making it a useful metric when focusing on muscle gain rather than weight loss.
- ✔Pairing FFMI with BMI helps clarify whether weight gain comes from muscle or fat.
FAQ
Q. What is FFMI?
FFMI divides your fat-free mass (muscle, bone, water — everything except fat) by height squared, revealing the muscle proportion of body weight that BMI misses. It's calculated by first removing body fat from total weight, then dividing by height(m) squared.
Q. What's the difference between FFMI and adjusted FFMI?
Adjusted FFMI, from Kouri et al. (1995), adds 6.1×(1.8 − height in m) to correct for the tendency of taller people to have a lower raw FFMI. At exactly 1.8 m the adjustment is zero, so the two values are identical.
Q. What does an adjusted FFMI of 25 mean?
It's an informal benchmark from the 1995 study, which found that non-steroid-using male bodybuilders rarely exceeded an adjusted FFMI of 25 — hence its reputation as a 'natural limit.' It is not an absolute cutoff, and individual variation exists.
Q. Can women use this calculator?
FFMI itself can be computed for anyone, but the 'average / muscular / natural limit' reference ranges come from a male bodybuilder sample, and no equivalent official range exists for women. Women should treat the raw numbers (fat-free mass, FFMI) as informational only.
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