Body Recomposition Calculator

Fat loss = deficit × 7 × weeks ÷ 7,700 kcal/kg. Muscle gain = an experience-based weekly rate × weeks. Fat and lean mass are tracked separately to project end weight and body-fat %.

Energy balance (7,700 kcal/kg fat); muscle-gain rates after Lyle McDonald and Alan Aragon models.

Recomposition is fastest for beginners, returners, and higher-body-fat starts. Advanced lifters near maintenance gain muscle very slowly, so treat projections as optimistic upper bounds.

Very lean athletes at their limit, and anyone under medical nutrition supervision.

Recomposition means losing fat and gaining muscle at the same time, so your weight may barely move while your body composition improves. It's done by eating near maintenance with a small deficit, training hard, and keeping protein high.

It works best for beginners, people returning after a break, and those carrying higher body fat — all of whom can build muscle while in a modest deficit. Lean, advanced lifters gain muscle very slowly and usually do better with separate cutting and bulking phases.

Fat loss comes from your calorie deficit using the 7,700 kcal-per-kilogram rule. Muscle gain uses realistic weekly rates by training experience — fastest for beginners, slowest for advanced lifters — tracked separately so you see both changes.

Aim high — around 2.2 g per kilogram of bodyweight. Protein is what lets you build muscle while in a deficit, and it protects the muscle you already have. The calculator sets a target for you.

That's the point of recomposition. If you're adding muscle at roughly the rate you're losing fat, the scale stays flat while your measurements, strength, and mirror all improve. Judge progress by photos, tape, and lifts — not weight alone.