Katch-McArdle calculator
Results
These values are estimates based on the Katch-McArdle formula.
| Body weight | Body fat | Lean mass (kg) | BMR (kcal/day) | TDEE (kcal/day) | Goal setting | Goal calories (kcal/day) | Activity level |
|---|
- Body weight:
- Body fat:
- Lean body mass:
- Basal metabolic rate (BMR):
- Total daily energy expenditure (TDEE):
- Goal setting:
- Goal calories:
- Activity level:
Daily macro targets from goal calories
| Nutrient | Percentage of calories | Calories per day | Grams per day |
|---|---|---|---|
| Protein | |||
| Carbohydrate | |||
| Fat |
All macro targets use goal calories; grams are rounded to the nearest whole number.
Example data table
These examples show how weight, body fat, activity, and goals change results.
| Scenario | Unit system | Weight | Body fat % | Activity level | Goal setting | BMR (kcal/day) | TDEE (kcal/day) | Goal calories (kcal/day) |
|---|---|---|---|---|---|---|---|---|
| Recreational athlete | Metric | 70 kg | 15% | Moderately active | Maintain | 1655 | 2566 | 2566 |
| Office worker | Metric | 85 kg | 25% | Lightly active | Mild fat loss (−10%) | 1747 | 2402 | 2162 |
| Sedentary beginner | Metric | 60 kg | 30% | Sedentary | Moderate fat loss (−20%) | 1277 | 1533 | 1226 |
Formula used
The Katch-McArdle equation estimates basal metabolic rate from lean body mass in kilograms.
- Lean body mass (kg) = weight (kg) × (1 − body fat% ÷ 100)
- BMR (kcal/day) = 370 + 21.6 × lean body mass (kg)
- TDEE (kcal/day) = BMR × activity factor
- Goal calories (kcal/day) = TDEE × (1 + goal change ÷ 100)
The activity factor reflects how much you move during a typical week.
How to use this calculator
- Select your preferred unit system: kilograms or pounds for body weight.
- Enter your current body weight and estimated body fat percentage.
- Choose the activity level that best matches your usual weekly routine.
- Select a goal setting or choose a custom calorie adjustment.
- Pick a macro preset or define your own macro percentages.
- Click "Calculate BMR, TDEE and macros" to generate results.
- Review calories, macro targets, and export them as CSV or PDF.
Notes and limitations
- This tool assumes body fat percentage is reasonably accurate from measurements or scans.
- Results are estimates, not medical advice or a clinical prescription.
- Large changes in weight, training, or health status require new measurements.
- Consult a qualified professional before making major dietary or training changes.
Why use the Katch-McArdle equation
The Katch-McArdle formula uses lean body mass instead of scale weight alone. This often gives more realistic calorie estimates for muscular, athletic, or very small framed individuals.
Because it emphasizes metabolically active tissue, it can provide better guidance when designing nutrition strategies around strength training, recomposition, or longer fat loss phases.
Estimating body fat for this calculator
You can estimate body fat from skinfold calipers, circumference methods, bioelectrical impedance scales, DEXA scans, or standardized photo charts that compare your appearance to reference images across body fat ranges.
Consistency matters more than perfection. Use the same estimation method regularly so trends in calculated BMR and TDEE remain comparable across weeks and training blocks.
Adjusting your calorie targets over time
If body weight or measurements are not moving toward your goal after several weeks, adjust the goal percentage slightly. Small systematic changes are safer than dramatic calorie cuts or large surpluses.
Recalculate after meaningful changes in body composition, training volume, or work routine. Updated lean mass values will automatically refresh BMR, TDEE, and macro recommendations.
Using this calculator with other tracking tools
Combine these estimates with food logging apps, step counters, and training trackers. Comparing predicted intake with real world progress helps you refine assumptions and improve long term planning accuracy.
Export CSV or PDF summaries regularly so you can review earlier settings, compare goal phases, and share structured data with coaches, trainers, or healthcare professionals.
Frequently asked questions
1. What does the Katch-McArdle calculator estimate?
It estimates your basal metabolic rate based on lean body mass, then multiplies by an activity factor to approximate total daily energy expenditure and suggested calorie targets for different body composition goals.
2. How accurate are these BMR and TDEE numbers?
They are educated estimates, not exact measurements. Individual metabolism can differ due to genetics, hormones, sleep, stress, and health. Use the results as a starting point, then adjust using actual progress over several weeks.
3. Do I need a perfectly accurate body fat percentage?
No, an approximate but consistent estimate is usually enough. Large errors in body fat will skew results, but small differences matter less if you recalculate periodically and monitor changes in body weight, measurements, and performance.
4. How often should I recalculate my numbers?
Recalculate whenever your body weight changes meaningfully, usually every four to eight weeks. Recalculating after big training changes, new jobs, or lifestyle shifts helps keep calorie and macro targets aligned with your current situation.
5. Can I change the macro presets safely?
Yes. Many people experiment with different macro splits while keeping total calories matched to their goal. Adjust protein, carbs, and fat within reasonable ranges and track energy, hunger, training performance, and recovery carefully.
6. Should I follow these numbers without professional guidance?
Healthy adults can often use these estimates independently, but anyone with medical conditions, complex medication regimens, or a history of disordered eating should discuss calorie and macro changes with a qualified healthcare or nutrition professional.