Know your genetic muscular potential.
Science-based, private, 100% free.

Yes. FFMI Calc is 100% free with no subscriptions and no in-app purchases. Every feature is available from day one.

No. FFMI Calc works immediately after download. No sign-up, no email, no registration of any kind.

Finnish, English, and Spanish. The app follows your selection across all screens and PDF reports.

Yes. All calculations run locally on your device. No internet connection is needed.

Fat-Free Mass Index (FFMI) measures your lean body mass relative to your height. It is a more meaningful metric than BMI for people who train with weights, because BMI cannot distinguish muscle from fat.

The FFMI formula uses Kouri et al. (1995) with height normalization from Schutz et al. (2002). Genetic potential is calculated using Casey Butt’s 4th edition model based on bone structure measurements.

It estimates the maximum lean mass you could naturally achieve based on your bone structure (wrist and ankle circumference) and height. This gives you a realistic ceiling for drug-free muscle growth.

You enter measurements for 6 body parts (chest, bicep, forearm, neck, thigh, calf). The app compares each against your genetic maximum and shows a percentage of potential reached.

No. All your data stays on your device. We have no servers, no analytics, and no tracking. We never see your measurements.

Yes. You can generate a professional 2-page PDF report with your FFMI score, genetic potential, body part analysis, and the full scientific methodology.

All data is permanently removed from your device. Since nothing is stored in the cloud, there is nothing else to delete.

Yes. FFMI Calc supports both male and female calculations with gender-specific formulas for FFMI scoring and genetic potential estimation.