A broad interpretation, not a verdict
Estimated lean mass from weight and body-fat input
FFMI · LEAN MASS · MUSCULARITY
How muscular am I? FFMI, normalized, in context.
Calculate Your FFMI
Calculate raw and normalized FFMI from your measurements or use a LeanLens body-fat range to see muscularity without pretending the inputs are exact.
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What does an FFMI calculator tell you?
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Try it with your photos.
Calculate raw and normalized FFMI from your measurements or use a LeanLens body-fat range to see muscularity without pretending the inputs are exact.
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FFMI
Enter your measurements for a deterministic fitness calculation.
FFMI
20.7
Normalized FFMI
20.7
Lean mass
67.1 kg
Fat mass
10.9 kg
Broad interpretation
Above average
Reference bands only; not a ceiling or classification.
Analysis
A broad interpretation, not a verdict
Calculate raw and normalized FFMI from your measurements or use a LeanLens body-fat range to see muscularity without pretending the inputs are exact.
From photo to FFMI
Raw fat-free mass index
Three ways to get more from FFMI
Height-normalized FFMI
Sex-aware broad reference bands
Sex-aware broad reference bands
A result range when body fat is supplied as a range
A result range when body fat is supplied as a range
Compare
From photo to FFMI
Fat-free mass index (FFMI) relates estimated lean mass to height. Normalized FFMI adjusts the result toward a 1.80 m reference so heights compare more fairly. It is useful as broad muscularity context and as a trend, but it is not a natty detector, proof of PED use, or a precise genetic ceiling.
1
A broad interpretation, not a verdict
Estimated lean mass from weight and body-fat input
2
From photo to FFMI
Raw fat-free mass index
3
Three ways to get more from FFMI
Height-normalized FFMI
How it works
Three ways to get more from FFMI
Calculate raw and normalized FFMI from your measurements or use a LeanLens body-fat range to see muscularity without pretending the inputs are exact.
01
A broad interpretation, not a verdict
FFMI is only as honest as the body-fat input. Even a small estimation error can noticeably move the result, so LeanLens keeps photo-based FFMI as a range instead of presenting a misleading decimal.
02
From photo to FFMI
A body analysis supplies a body-fat range. Enter that range with height and scale weight in the normalized FFMI calculator to estimate lean mass, raw FFMI, and normalized FFMI. For example, 80 kg at 1.80 m with 20% body fat gives 64 kg of lean mass and about 19.75 for both raw and normalized FFMI.
03
Three ways to get more from FFMI
Measure consistently, read the number alongside the photo and muscle-balance trend, and use reference bands as context rather than a ceiling to chase.
Trust
Photos of your body deserve care.
Privacy and honesty aren't features we bolted on; they shape how the product works.
Your photos, handled with care
One purpose: creating your results. Your photos are shared only with the providers needed to create or store them. Guest scans auto-delete; sign in and you can delete your saved photos and results anytime.
Honest by design
Ranges over false precision. No body-shaming mechanics, ever. Results describe, they don't judge. And nothing about your body is used to pressure you.
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Free includes an estimated body-fat range, confidence, summary, visible scores, photo-quality guidance, core detail for every available Muscle Balance result, and a limited focus view. Pro unlocks muscle history, bilateral and training-plan detail, deeper trends, strategy, and comparisons.
Pricing
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- Personalized strategy and focus plan
- Advanced trends and full comparison tools
- Estimated calorie and macro guidance when your profile details are available
Free accounts can scan again after a short wait. Pro removes the wait and unlocks full results, trends, and comparisons.
FAQ
Fair questions.
For an illustrative 60 kg person at 1.65 m, entering 25% body fat gives 45 kg lean mass, raw FFMI about 16.53 and normalized FFMI about 17.44. Entering 30% instead gives 42 kg, 15.43 and 16.34. The formula is the same for women and men; interpretation depends on the reference population and uncertain body-fat input.
Raw FFMI is fat-free mass in kilograms divided by height in metres squared. Normalized FFMI adjusts that value toward a 1.80 m reference.
No. FFMI cannot prove whether anyone has used performance-enhancing drugs.
Body fat determines estimated lean mass, so an inaccurate percentage directly changes the FFMI result.
Yes. The formula is the same, while broad interpretation bands are typically lower and must remain contextual.
Either can support your own trend when measured consistently; normalized FFMI is more useful for comparisons across different heights.
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One photo. Your muscularity, in context.
Calculate raw and normalized FFMI from your measurements or use a LeanLens body-fat range to see muscularity without pretending the inputs are exact.
No account required