BMR Calculator
Calculate your Basal Metabolic Rate based on age, weight, height, and gender.
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Measurements
What is BMR?
Basal Metabolic Rate (BMR) is the number of calories your body requires at complete rest to maintain vital physiological functions— including breathing, circulation, cell production, and temperature regulation. Unlike Total Daily Energy Expenditure (TDEE), which factors in activity, BMR isolates the energy cost of sustaining life’s baseline processes.
First studied in the early 20th century, BMR measurement became standard in nutritional science and clinical practice. Pioneering researchers like Du Bois & Du Bois (1916) developed the first equations relating body surface area to metabolic rate. Today, modern formulas—Mifflin–St Jeor, Harris–Benedict, and Katch–McArdle—offer tailored estimates based on weight, height, age, gender, and body composition.
How is BMR Calculated?
Several validated equations exist to estimate BMR. Select the formula that matches your data availability and goals:
| Formula | Equation | When to Use |
|---|---|---|
| Harris–Benedict | Male: 88.362 + (13.397 × W kg) + (4.799 × H cm) – (5.677 × Age) Female: 447.593 + (9.247 × W) + (3.098 × H) – (4.330 × Age) | Basic clinical settings |
| Mifflin–St Jeor | Male: (10 × W kg) + (6.25 × H cm) – (5 × Age) + 5 Female: (10 × W) + (6.25 × H) – (5 × Age) – 161 | General population; more accurate |
| Katch–McArdle | 370 + (21.6 × Lean Body Mass kg) | When you know body‑fat percentage |
Example Calculation
For a 30‑year‑old female, 65 kg, 170 cm tall:
- Mifflin–St Jeor: (10×65)+(6.25×170)−(5×30)−161 = 1 367 kcal/day
- Harris–Benedict: 447.593+(9.247×65)+(3.098×170)−(4.330×30) ≈ 1 378 kcal/day
Interpretation & Application
Knowing your BMR helps you:
- Design calorie‑controlled diets for weight loss, gain, or maintenance.
- Estimate Total Daily Energy Expenditure (TDEE) by adding activity multipliers.
- Monitor metabolic changes over time (e.g., aging, muscle gain).
Factors Influencing BMR Accuracy
- Body composition (muscle burns more calories than fat).
- Hormonal status (thyroid function, cortisol levels).
- Genetics and ethnic background.
- Environmental temperature.
Strategies to Boost BMR
- Increase Lean Mass: Resistance training stimulates muscle growth, raising resting energy needs.
- High‑Intensity Interval Training (HIIT): Short bursts of intense exercise elevate post‑exercise calorie burn.
- Protein‑Rich Diet: Protein has a higher thermic effect (20–30% of its calories are spent digesting).
- Hydration & Sleep: Dehydration and sleep deprivation can lower metabolic rate.
Summary
BMR is the cornerstone metric for personalized nutrition and fitness planning. By accurately estimating your resting energy needs and adjusting for lifestyle factors, you can craft effective diets, optimize performance, and track metabolic health over time.
References & External Resources
- Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. “A new predictive equation for resting energy expenditure in healthy individuals.” American Journal of Clinical Nutrition. 1990.
- Harris JA, Benedict FG. “A biometric study of human basal metabolism.” Proceedings of the National Academy of Sciences. 1918.
- NIH BMR Guidance:https://www.nhlbi.nih.gov/health/educational/lose_wt/BMR/bmr_tbl.htm
- Academy of Nutrition and Dietetics – Energy Expenditure:https://www.eatright.org/fitness/sports-and-performance/fueling-your-workout/calculating-your-calorie-needs
Frequently Asked Questions
What is Basal Metabolic Rate (BMR)?
BMR is the number of calories your body needs at rest to maintain vital functions.
Which formula do you use?
We support Mifflin–St Jeor, Harris–Benedict, and Katch–McArdle (requires body‑fat%).
How accurate is BMR?
Accuracy varies by individual: factors include body composition, hormones, genetics.
How do I use BMR?
Use BMR as a baseline—add activity or thermic effect factors for TDEE or diet planning.
Can I download results?
Yes—click 'Download CSV' to export your inputs and BMR result.