Your Results
Calculated body composition, maintenance calories, and goal-based daily energy targets appear here after submission.
Enter Your Details
Use either metric or imperial units. Choose a body fat method, then estimate calories for maintenance, fat loss, or muscle gain.
Example Data Table
These sample entries show how body fat percentage can change lean mass, maintenance calories, and goal calories across different activity levels.
| Profile | Gender | Weight | Body Fat % | Lean Mass | Maintenance | Goal Calories |
|---|---|---|---|---|---|---|
| Desk worker cutting | Male | 78 kg | 18% | 64.0 kg | 2440 kcal | 1940 kcal |
| Active runner maintaining | Female | 62 kg | 24% | 47.1 kg | 2210 kcal | 2210 kcal |
| Strength trainee gaining | Male | 86 kg | 15% | 73.1 kg | 3075 kcal | 3475 kcal |
| Beginner recomposition | Female | 70 kg | 31% | 48.3 kg | 2145 kcal | 1895 kcal |
Formula Used
- US Navy Body Fat: Uses logarithmic circumference equations with height, neck, waist, and hip for women.
- BMI Body Fat Estimate: Body fat % = (1.20 × BMI) + (0.23 × age) − (10.8 × sex) − 5.4, where sex = 1 for men and 0 for women.
- BMI: BMI = weight in kilograms ÷ height in meters².
- Lean Body Mass: Lean mass = body weight × (1 − body fat % ÷ 100).
- Fat Mass: Fat mass = body weight × (body fat % ÷ 100).
- Katch-McArdle BMR: BMR = 370 + (21.6 × lean body mass in kg).
- TDEE: Maintenance calories = BMR × activity multiplier.
- Goal Calories: Goal calories = maintenance calories + selected calorie adjustment.
- Weekly Change Estimate: Approximate weekly weight change = daily calorie adjustment × 7 ÷ 7700 kg equivalent.
Body fat formulas estimate, not diagnose. Direct scans and multi-site professional measurements are typically more accurate.
How to Use This Calculator
- Select your preferred unit system.
- Enter age, gender, height, and current weight.
- Choose a body fat method.
- For the Navy option, enter neck, waist, and hip if female.
- Pick your typical activity level.
- Select whether you want to maintain, lose, or gain.
- Choose a calorie adjustment matching your goal pace.
- Press Calculate to show the result section above the form.
- Review charts, calorie targets, and body composition metrics.
- Download your result summary as CSV or PDF.
Frequently Asked Questions
1. What does this calculator estimate?
It estimates body fat percentage, lean mass, fat mass, basal metabolism, maintenance calories, and a calorie target for losing, maintaining, or gaining weight.
2. Which body fat method is best?
The Navy method is often better than BMI when measurements are taken carefully. Manual input is best if you already know your tested body fat value.
3. Why use lean mass for calories?
Lean mass helps estimate resting calorie needs more specifically than total weight alone. That makes Katch-McArdle useful when body fat is available.
4. Are the calorie targets exact?
No. They are planning estimates. Real needs vary with sleep, stress, hormones, movement accuracy, medication use, digestion, and training changes.
5. How often should I recalculate?
Recalculate every two to four weeks, or after meaningful changes in weight, waist size, training volume, or body fat assessment.
6. Should I choose aggressive fat loss?
Aggressive deficits can work short term, but they may reduce performance, energy, and adherence. Moderate deficits are usually easier to sustain.
7. Can I use imperial measurements?
Yes. The calculator converts pounds and inches into metric values internally, then computes body fat and calories using the same formulas.
8. Does this replace professional advice?
No. It is an educational planning tool. Clinical nutrition, eating disorders, chronic illness, and medical weight management need qualified professional guidance.