Body Recomposition Calculator

Estimate simultaneous fat loss and muscle gain over a training block, based on training status, protein intake, and calorie balance — and see whether recomposition is realistic for your situation.

💪 Body Composition📐 Δ lean mass and Δ fat mass estimated from training status and energy balance🏥 Health

Current weight (kg)

Current body fat (%)

Training status

Sex

Calorie balance

Duration (weeks)

Protein intake (g/kg/day)

Please enter valid values.

Formula & Reference

Variable	Symbol	Formula	Units
Body Recomposition Calculator	—	Δ lean mass and Δ fat mass estimated from training status and energy balance	kg over period

Step-by-Step Examples

Example 1

Beginner Recomposition

80 kg male, 24% body fat, untrained, maintenance calories, 1.8 g/kg protein, 16 weeks.

Lean mass = 80 × 0.76 = 60.8 kg, fat mass = 19.2 kg
Beginner lean gain rate at maintenance with adequate protein
Modest fat loss at maintenance calories
Body fat falls several percentage points at similar body weight

✓ Meaningful recomposition — the classic beginner window

Example 2

Intermediate in a Deficit

75 kg male, 18% body fat, 2 years training, moderate deficit, 2.0 g/kg protein, 12 weeks.

Deficit reduces the lean gain rate to roughly 60% of maintenance
Fat loss proceeds steadily at around 0.6% body weight per week
Net result: clear fat loss with small lean gain

✓ Fat loss dominant, lean mass roughly preserved

Example 3

Advanced Lifter

82 kg male, 14% body fat, 5 years training, maintenance, 2.0 g/kg protein, 20 weeks.

Lean gain rate is low after several years of training
Fat loss at maintenance is minimal
Both changes are small over 20 weeks

✓ Marginal change — separate phases likely more productive

Real-World Applications

🆕

Beginner Gains

Untrained individuals can gain muscle and lose fat simultaneously at rates advanced lifters cannot match — this window closes with training age.

🥩

Protein Sufficiency

Adequate protein is the single most important variable for retaining and building lean mass while in a deficit.

🔄

Returning Athletes

Muscle memory allows previously trained individuals to regain lost mass far faster than building it the first time.

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Scale Weight Limits

Recomposition often shows little change on the scale, which is why body composition measurement matters more than weight here.

Common Mistakes to Avoid

⚠️

Expecting recomposition results as an advanced lifter

After several years of consistent training, simultaneous gain and loss becomes very slow. Dedicated building and cutting phases usually produce more progress.

⚠️

Under-eating protein while in a deficit

Protein needs rise, not fall, during a deficit. Intakes around 1.6–2.2 g/kg are commonly recommended for preserving lean mass.

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Judging progress by the scale

Recomposition by definition means weight changes little. Measurements, photos, and strength progression tell the story the scale hides.

Frequently Asked Questions

What is body recomposition? ▾

Losing fat and gaining muscle at the same time, rather than doing so in separate bulking and cutting phases.

Who can successfully recomp? ▾

It works best for people new to resistance training, those returning after a break, and people with higher body fat who have more stored energy to draw on.

How much protein do I need to recomp? ▾

Commonly cited targets are 1.6 to 2.2 g per kg of body weight per day, with the higher end favoured when in a calorie deficit.

Should I eat at maintenance or in a deficit? ▾

Maintenance or a small deficit tends to work best. Large deficits impair muscle gain, while surpluses shift the balance toward fat gain.

How long does recomposition take? ▾

Changes are gradual and typically become clearly visible over three to six months of consistent training and adequate protein.