Lose Weight and Gain Muscle Calculator
Your personalized guide to body recomposition and optimal nutrition.
Body Recomposition Calculator
Enter your details to get personalized calorie and macronutrient targets for losing fat and building muscle.
Enter your current body weight.
Centimeters (cm)
Inches (in)
Enter your height.
Enter your age in years.
Male
Female
Select your gender.
Sedentary (little or no exercise)
Lightly Active (light exercise/sports 1-3 days/week)
Moderately Active (moderate exercise/sports 3-5 days/week)
Very Active (hard exercise/sports 6-7 days a week)
Extra Active (very hard exercise/sports & physical job or 2x training)
Choose the option that best describes your lifestyle.
Estimate your body fat percentage (optional, but improves accuracy).
Lose Fat & Gain Muscle
Gain Muscle (with minimal fat gain)
Lose Weight (focus on fat loss)
Select your main fitness objective.
Your Body Recomposition Targets
— kcal
Target Daily Calorie Intake
—g
Protein
—g
Carbohydrates
—g
Fat
How it works: We first estimate your Basal Metabolic Rate (BMR) using the Mifflin-St Jeor equation, then multiply by your activity level to get your Total Daily Energy Expenditure (TDEE). Calorie and macronutrient targets are adjusted based on your primary goal (lose fat, gain muscle, or recomposition).
Equations Used:
Mifflin-St Jeor BMR (kcal/day):
Male: (10 * weight_kg) + (6.25 * height_cm) – (5 * age) + 5
Female: (10 * weight_kg) + (6.25 * height_cm) – (5 * age) – 161
TDEE = BMR * Activity Factor
Calorie Adjustment: Based on goal (e.g., -300 to -500 kcal for fat loss, +200 to +300 kcal for muscle gain).
Macronutrient Split (approximate):
Protein: 1.6-2.2g per kg of lean body mass or total weight
Fat: 20-30% of total calories
Carbohydrates: Remaining calories.
Equations Used:
Mifflin-St Jeor BMR (kcal/day):
Male: (10 * weight_kg) + (6.25 * height_cm) – (5 * age) + 5
Female: (10 * weight_kg) + (6.25 * height_cm) – (5 * age) – 161
TDEE = BMR * Activity Factor
Calorie Adjustment: Based on goal (e.g., -300 to -500 kcal for fat loss, +200 to +300 kcal for muscle gain).
Macronutrient Split (approximate):
Protein: 1.6-2.2g per kg of lean body mass or total weight
Fat: 20-30% of total calories
Carbohydrates: Remaining calories.
Body Recomposition: The Science of Losing Fat and Gaining Muscle
Projected weekly progress based on calculator inputs.
Key Macronutrient Breakdown
| Macronutrient | Grams per kg Body Weight (Typical Range) | Grams per lb Body Weight (Typical Range) | Approximate % of Calories |
|---|---|---|---|
| Protein | 1.6 – 2.2 g/kg | 0.7 – 1.0 g/lb | 25-35% |
| Fat | 0.5 – 1.0 g/kg | 0.2 – 0.5 g/lb | 20-30% |
| Carbohydrates | Variable (remainder of calories) | Variable (remainder of calories) | 35-55% |
Note: These are general guidelines and can be adjusted based on individual response and training intensity.
What is Body Recomposition?
Body recomposition, often referred to as the "lose weight and gain muscle" process, is a fitness goal focused on simultaneously reducing body fat and increasing lean muscle mass. Unlike traditional dieting which often leads to muscle loss alongside fat loss, or bulking which prioritizes muscle gain potentially at the expense of fat, body recomposition aims for a more balanced transformation. This approach is particularly appealing to individuals who are new to strength training, those returning after a break, or individuals with higher body fat percentages who want to sculpt a leaner, more muscular physique without significant weight fluctuations. It requires a meticulous approach to nutrition and training, focusing on sufficient protein intake, strategic calorie cycling, and progressive resistance exercise. Common misconceptions include believing it's impossible or requires extreme measures; in reality, it's achievable with consistency and the right strategy.
Body Recomposition Formula and Mathematical Explanation
The core of achieving body recomposition lies in managing energy balance and providing the body with the necessary building blocks for muscle growth while encouraging fat utilization. The process typically revolves around calculating your Total Daily Energy Expenditure (TDEE) and then strategically setting your daily calorie and macronutrient intake.
Step 1: Estimate Basal Metabolic Rate (BMR)
We use the Mifflin-St Jeor equation, considered one of the most accurate methods:
- For Men: BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5
- For Women: BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161
This calculates the calories your body burns at rest.
Step 2: Calculate Total Daily Energy Expenditure (TDEE)
Your TDEE is your BMR multiplied by an activity factor that reflects your lifestyle:
TDEE = BMR × Activity Factor
Step 3: Set Calorie Target for Recomposition
This is where the strategy for losing weight and gaining muscle comes in. The goal is a slight calorie deficit or maintenance, paired with high protein intake and resistance training.
- Lose Fat & Gain Muscle (Recomposition): A small deficit (e.g., 200-500 kcal below TDEE) is often optimal. This allows for fat loss while providing enough energy and nutrients for muscle repair and growth.
- Gain Muscle (Lean Bulk): A small surplus (e.g., 200-300 kcal above TDEE) to fuel muscle protein synthesis with minimal fat gain.
- Lose Weight (Fat Loss Focus): A moderate deficit (e.g., 300-500 kcal below TDEE) to prioritize fat reduction, often with slightly lower carbs.
Step 4: Determine Macronutrient Split
Once the calorie target is set, macronutrients are distributed:
- Protein: Crucial for muscle repair and growth. Aim for 1.6 to 2.2 grams per kilogram of body weight (or 0.7 to 1.0 grams per pound). This is often prioritized.
- Fat: Essential for hormone production. Aim for 20-30% of total daily calories. A common target is 0.5 to 1.0 grams per kilogram of body weight.
- Carbohydrates: Provide energy for workouts and daily activities. The remaining calories after protein and fat are allocated to carbohydrates.
Variables Table:
| Variable | Meaning | Unit | Typical Range / Notes |
|---|---|---|---|
| Weight | Body mass of the individual | kg / lb | Subjective |
| Height | Body height of the individual | cm / in | Subjective |
| Age | Age of the individual | Years | Subjective |
| Gender | Biological sex (influences BMR calculation) | N/A | Male / Female |
| Activity Factor | Multiplier based on daily physical activity | Multiplier | 1.2 – 1.9 |
| Body Fat Percentage | Proportion of body weight that is fat | % | Optional, improves accuracy. 10-40% (typical) |
| BMR | Basal Metabolic Rate | kcal/day | Calculated |
| TDEE | Total Daily Energy Expenditure | kcal/day | Calculated (BMR x Activity Factor) |
| Calorie Target | Daily calorie intake for goal achievement | kcal/day | TDEE +/- Adjustment based on goal |
| Protein Target | Daily protein intake | g / day | 1.6-2.2 g/kg body weight |
| Fat Target | Daily fat intake | g / day | 20-30% of calories or 0.5-1.0 g/kg |
| Carbohydrate Target | Daily carbohydrate intake | g / day | Remaining calories |
Practical Examples (Real-World Use Cases)
Example 1: Sarah, aiming for recomposition
- Inputs:
- Current Weight: 68 kg
- Height: 165 cm
- Age: 28
- Gender: Female
- Activity Level: Moderately Active (1.55)
- Body Fat %: 30%
- Goal: Lose Fat & Gain Muscle
- Calculations:
- BMR (Female): (10*68) + (6.25*165) – (5*28) – 161 = 680 + 1031.25 – 140 – 161 = 1410.25 kcal
- TDEE: 1410.25 * 1.55 = 2186 kcal
- Calorie Target (small deficit): 2186 – 400 = 1786 kcal (round to 1800 kcal)
- Protein Target: 1.8g/kg * 68kg = 122.4g (round to 125g) -> 500 kcal
- Fat Target: 25% of 1800 kcal = 450 kcal -> 50g
- Carbohydrate Target: 1800 – 500 (protein) – 450 (fat) = 850 kcal -> 212.5g (round to 210g)
- Outputs:
- Primary Result: 1800 kcal
- Protein: 125g
- Carbs: 210g
- Fat: 50g
- Interpretation: Sarah should aim for approximately 1800 calories per day, with a strong emphasis on protein (125g). This intake should support fat loss while providing adequate fuel for muscle growth, especially when combined with consistent strength training.
Example 2: Mark, focusing on muscle gain with minimal fat
- Inputs:
- Current Weight: 85 kg
- Height: 180 cm
- Age: 25
- Gender: Male
- Activity Level: Very Active (1.725)
- Body Fat %: 18%
- Goal: Gain Muscle (with minimal fat gain)
- Calculations:
- BMR (Male): (10*85) + (6.25*180) – (5*25) + 5 = 850 + 1125 – 125 + 5 = 1855 kcal
- TDEE: 1855 * 1.725 = 3200 kcal
- Calorie Target (small surplus): 3200 + 250 = 3450 kcal
- Protein Target: 2.0g/kg * 85kg = 170g -> 680 kcal
- Fat Target: 25% of 3450 kcal = 862.5 kcal -> 96g (round to 95g)
- Carbohydrate Target: 3450 – 680 (protein) – 862.5 (fat) = 1907.5 kcal -> 477g (round to 475g)
- Outputs:
- Primary Result: 3450 kcal
- Protein: 170g
- Carbs: 475g
- Fat: 95g
- Interpretation: Mark needs around 3450 calories daily to support significant muscle gain. High protein intake (170g) is crucial, with carbohydrates providing ample energy for intense training sessions. Monitoring weight and body composition will help fine-tune the calorie surplus to minimize excessive fat accumulation.
How to Use This Lose Weight and Gain Muscle Calculator
Our calculator simplifies the complex process of determining optimal nutrition for body recomposition. Here's a step-by-step guide:
- Input Your Details: Accurately enter your current weight, height, age, gender, and select your typical activity level. Providing an estimated body fat percentage, if known, will yield more precise results.
- Select Your Goal: Choose the primary objective that best reflects your current fitness aspirations: "Lose Fat & Gain Muscle" (recomposition), "Gain Muscle" (lean bulk), or "Lose Weight" (fat loss focus).
- Calculate: Click the "Calculate" button. The calculator will instantly display your target daily calorie intake, along with recommended grams of protein, carbohydrates, and fat.
- Understand the Results:
- Primary Result (Calories): This is your target daily calorie intake. For recomposition, it's typically a slight deficit or maintenance level.
- Macronutrients (Protein, Carbs, Fat): These are the grams of each macronutrient you should aim for daily. Protein is emphasized for muscle support, while fats are kept moderate, and carbs fill the remaining energy needs.
- Formula Explanation: Review the "How it works" section to understand the underlying principles (BMR, TDEE, and macronutrient distribution).
- Actionable Guidance: Use these numbers as a starting point. Track your food intake using a reliable method (like a food logging app) and monitor your progress (weight, measurements, strength gains) weekly. Adjust your intake slightly (e.g., +/- 100-200 calories) based on your results and how you feel. Consistency in training and nutrition is key.
- Reset: Use the "Reset" button to clear current inputs and start over, perhaps to explore different scenarios or correct an entry.
- Copy Results: The "Copy Results" button allows you to easily save or share your calculated targets.
Key Factors That Affect Lose Weight and Gain Muscle Results
While the calculator provides a solid foundation, several factors significantly influence your success with body recomposition:
- Training Stimulus: Progressive overload in resistance training is non-negotiable. You must consistently challenge your muscles to signal them to grow. Without adequate training stimulus, your body has little reason to build muscle, even in a calorie surplus.
- Protein Intake Consistency: Hitting your protein target daily is critical. Insufficient protein intake hinders muscle protein synthesis and can lead to muscle loss, even if calories are adequate. Spreading protein intake throughout the day is also beneficial.
- Sleep Quality and Quantity: Muscle repair and growth predominantly occur during sleep. Poor sleep disrupts hormone balance (increasing cortisol, decreasing testosterone/growth hormone), impairing recovery and muscle gain while potentially increasing fat storage. Aim for 7-9 hours of quality sleep.
- Stress Management: Chronic high stress elevates cortisol levels, which can promote fat storage (especially abdominal fat) and muscle breakdown. Incorporating stress-reducing activities like meditation, yoga, or hobbies is vital for a favorable hormonal environment.
- Nutrient Timing (Secondary): While total daily intake is paramount, consuming protein and carbohydrates around your workouts can optimize recovery and performance. However, this is less critical than overall daily intake for most individuals.
- Hydration: Water is essential for numerous bodily functions, including nutrient transport, temperature regulation, and cellular processes involved in muscle repair. Dehydration can negatively impact performance and recovery.
- Cardiovascular Exercise: While not directly building muscle, moderate cardio aids fat loss, improves cardiovascular health, and can enhance recovery by improving blood flow. However, excessive cardio can interfere with muscle gain if not managed properly with nutrition and recovery.
- Consistency and Patience: Body recomposition is a slower process than traditional bulking or cutting. It requires sustained effort over weeks and months. Expect gradual changes rather than rapid transformations.
Frequently Asked Questions (FAQ)
Can I truly lose weight and gain muscle at the same time?
Yes, it's possible, especially for beginners, individuals returning after a layoff, or those with higher body fat percentages. It requires a precise balance of nutrition (high protein, slight calorie deficit or maintenance) and progressive resistance training. It's generally a slower process than focusing on just one goal.
How much of a calorie deficit is optimal for recomposition?
A small deficit, typically between 200-500 calories below your TDEE, is usually recommended. This allows for fat mobilization without significantly compromising muscle protein synthesis or energy levels for training.
What if I don't know my body fat percentage?
The calculator still works effectively using general formulas. However, if you can get an estimate (e.g., using smart scales, calipers, or visual guides), inputting it will refine the results, particularly in calculating lean body mass for protein targets. You can proceed without it; the results will be based on total body weight.
How important is workout intensity for recomposition?
Extremely important. To signal your body to build muscle, you need to provide a strong stimulus through progressive overload. This means gradually increasing the weight, reps, or sets over time. Without this stimulus, your body prioritizes energy conservation over muscle growth.
Should I cycle my calories (high/low days)?
Some individuals find calorie cycling beneficial for recomposition. This might involve slightly higher calories on training days (to fuel workouts and recovery) and lower calories on rest days (to enhance fat loss). However, the total weekly calorie intake remains the primary driver. The calculator provides a daily average.
How long does body recomposition typically take?
It varies greatly depending on genetics, training history, starting body fat percentage, adherence to diet, and consistency. For beginners, noticeable changes can occur within 8-12 weeks. More advanced individuals may take longer, potentially months or even years, to achieve significant body composition shifts. Patience is key.
Can supplements help with losing weight and gaining muscle?
Supplements are secondary to diet and training. Protein powders (whey, casein, plant-based) can help meet protein goals conveniently. Creatine monohydrate is well-researched for improving strength and muscle mass. However, focus on foundational elements first; supplements only complement a solid plan.
What if my weight is stalling but I feel stronger?
This is a common scenario in body recomposition. Muscle tissue is denser than fat tissue. If you're gaining muscle while losing fat, your scale weight might remain stable or change very slowly. Focus on other progress indicators like how your clothes fit, body measurements, strength increases in the gym, and visual appearance.