計算您的無脂體重指數 (FFMI)
使用我們的專業FFMI計算器，獲得準確的身體成分分析並追蹤您的健身進度。適合運動員、健美運動員和健身愛好者。
調整後FFMI
經身高調整的FFMI，更準確地反映您的肌肉發展水平。這是主要參考值。
體脂率
使用Deurenberg公式（BMI + 年齡 + 性別）計算，並根據體型調整。
Deurenberg公式：體脂率 = (1.2×BMI + 0.23×年齡 - 5.4) - 10.8×性別
肌肉量
您的總瘦體重和身體成分分解
解讀
基於您的調整後FFMI值的評估。
建議
基於您的FFMI值和體型特徵的個人化建議。
訓練重點
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營養建議
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目標設定
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計算器
年齡用於Deurenberg公式以準確計算體脂率
選擇您的體型以估算體脂率
儲存您的記錄
將當前計算結果儲存到歷史記錄，方便追蹤您的進度
暫無歷史記錄
開始計算您的FFMI以追蹤您的進度
What is FFMI (Fat-Free Mass Index)?
The Fat-Free Mass Index (FFMI) is a measurement that evaluates the amount of muscle mass you carry relative to your height. Unlike BMI, which treats all weight equally, FFMI specifically focuses on lean body mass—giving you a more accurate picture of your muscular development.
The FFMI Formula
Fat-Free Mass (FFM) = Weight × (1 - Body Fat %)
FFMI = FFM / Height²
Normalized FFMI = FFMI + 6.1 × (1.8 - Height)
The normalized FFMI adjusts for height differences, making comparisons between individuals more accurate. This correction was introduced by Kouri et al. (1995) in their landmark study.
Why FFMI is Better Than BMI for Athletes
BMI (Body Mass Index) has a fundamental flaw: it cannot distinguish between muscle and fat. A muscular athlete and an overweight sedentary person can have identical BMI scores, despite having completely different body compositions.
BMI Limitations
- • Cannot differentiate muscle from fat
- • Labels muscular people as "overweight"
- • Ignores body composition entirely
- • Not useful for fitness tracking
FFMI Advantages
- • Measures actual muscle mass
- • Accounts for body fat percentage
- • Height-normalized for fair comparison
- • Research-backed interpretation ranges
FFMI Score Interpretation
Understanding what your FFMI score means is crucial for setting realistic fitness goals. These ranges are based on research studies of both natural and enhanced athletes.
| FFMI Range | Category | Description |
|---|---|---|
| < 18 | Below Average | Little muscle development. Common in untrained individuals or those new to fitness. |
| 18 - 20 | Average | Typical for recreationally active men. Some visible muscle definition. |
| 20 - 22 | Above Average | Good muscular development. 1-3 years of consistent training typically required. |
| 22 - 23 | Excellent | Very muscular. Noticeably athletic build. 3-5+ years of dedicated training. |
| 23 - 25 | Superior | Elite natural development. Near genetic potential for most individuals. |
| > 25 | Exceptional | Exceeds typical natural limits. May indicate elite genetics or PED use. |
Important Note on the "Natural Limit"
The FFMI of 25 is often cited as the "natural limit," based on Kouri et al.'s 1995 study. However, this should be viewed as a general guideline, not an absolute rule. Genetics, measurement accuracy, and individual variation all play significant roles.
How to Use Your FFMI Score
Track Progress
Calculate your FFMI regularly (monthly or quarterly) to objectively track muscle gains. Unlike weight alone, FFMI shows if you are building lean mass.
Set Realistic Goals
Use FFMI ranges to set achievable targets. First-year gains are typically 2-3 FFMI points. Knowing your ceiling helps plan long-term.
Compare Fairly
FFMI normalizes for height, allowing fair comparison across different body sizes. A 5'6" and 6'2" lifter can be compared directly.
Assess Naturally
FFMI can help you evaluate whether physiques you see online are naturally achievable, helping set more realistic expectations.
什麼是FFMI？
無脂體重指數（FFMI）是一種幫助您了解相對於身高的肌肉量的測量方法。與身體質量指數（BMI）不同，BMI無法區分脂肪和肌肉，而FFMI專門測量您的瘦肌肉量。
FFMI是1990年代研究合成代謝類固醇對肌肉量影響的研究人員開發的。Kouri等人在1995年進行的開創性研究發現，自然健美運動員的FFMI很少超過25，而類固醇使用者的數值通常高於這一閾值。
FFMI為何重要：
- 隨時間追蹤肌肉增長進度
- 設定現實的自然健美目標
- 公平地比較您與他人的體格
- 識別您是否達到遺傳潛力
使用FFMI的好處
精準追蹤
與BMI不同，FFMI專門測量肌肉量，為您提供更準確的身體成分和健身進度圖像。
設定現實目標
了解您的自然增肌潛力，並基於科學研究和數據設定可實現的目標。
基於證據
基於領先運動科學機構的同儕審查研究，為您提供可靠和值得信賴的結果。
常見問題
FFMI和標準化FFMI有什麼區別？
常規FFMI是您的原始計算值，而標準化FFMI會調整身高以允許不同身高人群之間的公平比較。標準化公式將每個人的FFMI調整為假設身高為1.8公尺（約5英尺11英寸）時的數值。這是討論自然極限時通常使用的值。
體脂率需要多精確？
體脂率的準確性對FFMI計算至關重要。體脂測量中5%的誤差可能會使您的FFMI改變2-3個點。為獲得最佳結果，請使用DEXA掃描或專業身體成分分析。目測估計或基本皮褶卡尺的誤差可能達到5-10%，嚴重影響您的結果。
我可以自然地將肌肉增長到FFMI超過25嗎？
可以，但很罕見。對大學運動員的最新研究顯示，約有2.5%的人自然達到FFMI超過28。因素包括卓越的遺傳、從年輕時開始的最佳訓練、特定運動的適應性以及非凡的恢復能力。大多數自然健身者會在22-25 FFMI之間達到平台期。
作為自然健身者，我應該以什麼FFMI為目標？
對於大多數專注的自然健身者來說，現實的目標是FFMI 21-23。這代表透過5-10年持續訓練可實現的出色肌肉發展。FFMI超過23需要卓越的遺傳以及多年近乎完美的訓練和營養。
FFMI對女性的作用相同嗎？
FFMI公式對女性的計算方式相同，但由於肌肉量潛力的生物學差異，參考範圍不同。女性天然具有更高的體脂率和更低的肌肉量。女性FFMI 17-19被認為是優秀的，而19-21對於自然運動員來說是精英水平。自然情況下超過21的數值極為罕見。
More Questions About FFMI
What body fat percentage do I need to calculate FFMI?
You need to know your body fat percentage to calculate FFMI accurately. Common methods include: DEXA scans (most accurate), bioelectrical impedance scales, skinfold calipers, or visual estimation. If you don't know your body fat, use our Body Fat Calculator first, or try our FFMI estimator that works without it.
Is FFMI accurate for women?
The original FFMI research primarily studied men. For women, the scale is different: an FFMI of 15-17 is average, 17-19 is above average, and 19-21 is excellent. Women naturally carry less muscle mass, so direct comparison to male ranges is not appropriate.
Can FFMI detect steroid use?
FFMI alone cannot definitively detect steroid use. While scores above 25 are rare naturally, some individuals with exceptional genetics may exceed this. Conversely, many steroid users have FFMIs below 25. Use FFMI as one data point, not a definitive test.
How often should I measure my FFMI?
Muscle building is slow—measuring monthly or quarterly is sufficient. More frequent measurements may show fluctuations due to water retention, food intake, and measurement error rather than actual muscle changes. Track trends over months, not weeks.
Does FFMI account for bone density or frame size?
No, FFMI does not directly account for bone density or skeletal frame size. Individuals with larger frames may have slightly higher FFMIs. Some researchers have proposed adjusted formulas, but the standard FFMI remains the most widely used and researched version.
科學研究
Kouri等人（1995）
建立基線值的原始FFMI研究：
- 類固醇使用者：平均24.8 FFMI
- 自然健身者：平均21.8 FFMI
- 沒有自然健身者超過FFMI 25
NCAA研究（2017）
關於大學運動員的研究：
- 26.4%的人FFMI超過25
- 挑戰嚴格的自然極限
- 注意到特定運動的差異
最新研究（2019-2023）
現代研究發現：
- 特定運動的FFMI差異
- 遺傳和訓練因素
- 自然極限超過25
Scientific References
Kouri EM, Pope HG Jr, Katz DL, Oliva P. (1995)
"Fat-free mass index in users and nonusers of anabolic-androgenic steroids."
Clinical Journal of Sport Medicine, 5(4):223-228.
Schutz Y, Kyle UU, Pichard C. (2002)
"Fat-free mass index and fat mass index percentiles in Caucasians aged 18-98 y."
International Journal of Obesity, 26(7):953-960.
VanItallie TB, Yang MU, Heymsfield SB, et al. (1990)
"Height-normalized indices of the body's fat-free mass and fat mass."
American Journal of Clinical Nutrition, 52(6):953-959.
Medical Disclaimer
This calculator provides estimates for educational and informational purposes only. It is not medical advice and should not be used as a substitute for professional medical guidance. The FFMI metric has limitations and may not accurately represent all individuals. Consult a healthcare professional or certified fitness trainer before making decisions based on these calculations.