Your Personal Recomp Numbers — Without the Guesswork
Most people are told to pick one: lose fat or gain muscle. But body recomposition — losing fat and building muscle simultaneously — is genuinely possible for the right person, and it comes down to two numbers most people never calculate properly: a calorie target that sits in a small, deliberate deficit, and a protein target high enough to protect and build muscle while the fat comes off.
This free body recomp calculator turns your weight and body fat percentage into a clear plan. You will see your estimated lean mass and fat mass in kilograms, your daily calorie target range, your protein goal in grams per day, and your estimated maintenance calories — with the exact math shown, step by step. No account, no download, everything runs in your browser.
The short version of how it works: we estimate your lean body mass from your body fat percentage, use it to calculate your resting calorie burn (the Katch-McArdle equation, which is built for exactly this), adjust for your activity level, then set calories slightly below maintenance and protein at 1.6–2.2 grams per kilogram of bodyweight. That combination is the nutritional backbone of every successful recomp.
How to Use This Body Recomp Calculator
- Enter your current body weight — kg or lb. Morning weight before eating is the most consistent measurement.
- Enter your body fat percentage. A best guess works fine: smart scales, calipers, tape-measure estimates, or comparing yourself to visual reference charts. Most men fall between 10–25%, most women between 18–32%.
- Pick your goal. Choose “Recomp” for simultaneous fat loss and muscle gain, “Lose fat” for a dedicated cut, or “Gain muscle” for a lean bulk.
- Pick your activity level — and be honest. Overestimating activity is the number-one way people accidentally eat at maintenance instead of in a deficit.
- Tap Calculate My Targets. Read your calorie range at the top, then the stat grid: lean mass, fat mass, protein target, and maintenance calories. The math box shows every calculation.
What Is Body Recomposition?
Body recomposition (“recomp”) means changing what your weight is made of rather than simply changing the number on the scale: decreasing fat mass while increasing (or at least maintaining) muscle mass. During a good recomp the scale may barely move — but your waist shrinks, your clothes fit differently, and you look visibly more athletic.
It works because muscle growth is driven mostly by training stimulus plus protein, while fat loss is driven mostly by a calorie deficit. A small deficit (roughly 5–10% below maintenance) leaves enough energy available for muscle building while forcing the body to pull the rest from stored fat. High protein — about 1.6–2.2 grams per kilogram of bodyweight per day — supplies the raw material for new muscle.
Recomp is most effective for beginners, people returning to training after a break, and those with moderate-to-higher body fat, because their bodies have both a strong growth signal and abundant stored energy. If you are already very lean and advanced, dedicated cutting and bulking phases usually produce faster visible change.
The Body Recomp Formula (With a Worked Example)
Fat mass = Weight × Body fat %
Resting burn (Katch-McArdle) = 370 + 21.6 × Lean mass (kg)
Maintenance (TDEE) = Resting burn × Activity factor
Recomp calories = TDEE × 0.90 to 0.95
Protein = Weight (kg) × 1.6 to 2.2 g/kg
Worked example: an 80 kg person at 20% body fat, moderately active.
- Lean mass = 80 × (1 − 0.20) = 64 kg; fat mass = 80 × 0.20 = 16 kg
- Resting burn = 370 + 21.6 × 64 = 1,752 kcal/day
- Maintenance = 1,752 × 1.55 (moderate activity) = ~2,716 kcal/day
- Recomp target = 2,716 × 0.90 to 0.95 = ~2,445–2,580 kcal/day
- Protein = 80 × 1.6–2.2 = 128–176 g/day
That is exactly what the tool above computes for those inputs — and the result panel shows the same breakdown for your own numbers.
Calorie Cycling: An Alternative Recomp Setup
The formula above gives you one flat daily target — about 2,445–2,580 for the worked example’s 2,716 kcal maintenance. But you don’t have to eat the same number every day. Calorie cycling distributes the same weekly deficit unevenly: eat at or near maintenance on training days, and run a deeper deficit on rest days, when the body can draw on stored fat.
Here is what that looks like with the example’s 2,716 kcal maintenance. Train 4 days a week at full maintenance (2,716), and eat 15% below it — about 2,309 — on the 3 rest days. The weekly average is (4 × 2,716 + 3 × 2,309) ÷ 7 ≈ 2,542 kcal/day, which sits about 6.4% below maintenance — right inside the recomp range. Same deficit, but training days stay fully fueled.
Cycling is not magic — the weekly average drives fat loss — but training days at maintenance fuel better workouts, and a deeper rest-day deficit can be easier to stick to than a constant small one. Keep protein high every day.
Limitations of the Body Recomp Calculator
- Body fat estimates are imprecise. Smart scales, calipers, and visual guesses can be off by several percentage points, and that error flows into your lean-mass and calorie numbers. Treat results as a starting point, not a lab measurement.
- It assumes average metabolism. Thyroid conditions, medications, very high or low muscle mass, and age extremes can shift your true calorie burn by a few hundred calories either way.
- Recomp is slow by nature. Expect visible change over months, not weeks — roughly 0.5–1% of body fat lost per month is a realistic pace. The scale will mislead you; track waist measurements, photos, and gym performance instead.
- Not ideal for everyone. Very lean, advanced lifters generally get better results from separate cutting and bulking phases.
- This is an estimate, not medical advice. If you have a medical condition, an eating-disorder history, or are pregnant, talk to a clinician or registered dietitian before changing your diet.
Recomp Tips That Actually Matter
- Lift with progressive overload. Add weight or reps over time — the training signal is what makes recomp possible at all. 3–5 strength sessions per week beats random cardio for this goal.
- Hit the top of the protein range. When in doubt, aim for 2.0 g/kg. Spread it across 3–5 meals so muscle protein synthesis stays elevated through the day.
- Sleep 7–9 hours. Poor sleep raises hunger hormones and directly impairs muscle retention during a deficit — it is as important as the calorie math.
- Weigh yourself 3–4 times a week and use the average. Daily weight swings 1–2 kg from water and food; the weekly average is the only number worth reacting to.
- Give it 8–12 weeks before judging. Recomp rewards patience. Reassess calories only after a full month of consistent training and eating.
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Frequently Asked Questions
Can you really lose fat and gain muscle at the same time?
Yes — it is called body recomposition, and research shows it works best for beginners, people returning to training, and those with moderate-to-higher body fat. The recipe is a small calorie deficit (5–10% below maintenance), high protein (1.6–2.2 g/kg/day), and progressive strength training.
How many calories should I eat for body recomp?
Start at 90–95% of your maintenance calories — a small deficit that still leaves energy for muscle growth. For example, if your maintenance is 2,700 kcal/day, your recomp range is roughly 2,430–2,565 kcal/day.
How much protein do I need for recomp?
Aim for 1.6–2.2 grams of protein per kilogram of bodyweight per day (about 0.7–1.0 g per pound). An 80 kg person targets roughly 128–176 g of protein daily. Higher within that range is safer during a deficit.
How long does body recomposition take?
Visible changes typically take 8–12 weeks of consistent training and nutrition. Because fat loss and muscle gain can cancel out on the scale, judge progress by waist measurements, progress photos, and strength gains — not just weight.
Is recomp better than bulking and cutting?
For beginners and people with higher body fat, recomp is usually the better choice — you improve both sides at once. Lean, advanced lifters generally progress faster with dedicated cut and bulk phases, because true recomp slows down as you get leaner.
What is the Katch-McArdle equation?
It is a formula that estimates resting calorie burn from lean body mass: 370 + 21.6 × lean mass (kg). Because it uses lean mass rather than total weight, it adapts better to different body compositions than weight-only formulas.
Do I need cardio for body recomp?
Cardio is optional but useful — it improves conditioning and adds a little to your calorie deficit. Strength training is the non-negotiable part; 2–3 short cardio sessions per week on top of lifting is plenty for most people.
Should I eat the same calories every day during a recomp?
You can cycle them: eat near maintenance on training days and run a deeper deficit on rest days, as long as the weekly average stays 5–10% below maintenance. For example, 4 training days at maintenance plus 3 rest days at 15% below still lands you in the recomp range — and many people train better with fully fueled training days.
How much muscle can I realistically gain during a recomp?
Beginners can realistically gain around 0.25–0.5 kg of muscle per month during a well-run recomp; intermediate and advanced lifters should expect less. That slow pace is exactly why recomp is judged over 8–12 weeks, not two — and why the scale is the wrong measuring tool for it.
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