BMR Calculator: Harris-Benedict vs Mifflin
Compare two widely used basal metabolic rate equations and see how their resting calorie estimates differ for your body stats.
Compare BMR Formulas
Medical Disclaimer: This is for informational purposes only—not medical advice. Consult a healthcare professional.
How this is calculated
Formula: Mifflin-St Jeor compared with revised Harris-Benedict
Mifflin-St Jeor uses weight, height, age, and a sex-specific constant. It was published in 1990 and is frequently used as a default estimate for modern adults.
The revised Harris-Benedict equations use the same inputs with different coefficients. They update the original 1919 formulas and can return a modestly different BMR.
Both values represent predicted resting energy use, not total daily calories. To estimate TDEE, multiply a BMR estimate by an appropriate activity factor and validate it against real-world trends.
Mifflin-St Jeor and Harris-Benedict compared
| Equation | Key characteristic | Practical use |
|---|---|---|
| Mifflin-St Jeor | Published 1990 | Common default for general adult estimates |
| Revised Harris-Benedict | Revised 1984 | Useful second estimate for comparison |
| Measured RMR | Indirect calorimetry | Clinical measurement when precision is important |
Choosing between two BMR estimates
A small difference between formulas is normal and usually matters less than selecting a realistic activity level or tracking intake consistently.
Tips
- •Use Mifflin-St Jeor as a sensible starting point for most adults.
- •Treat the difference between equations as an uncertainty range.
- •Do not confuse BMR with the calories needed for a full day.
- •Use observed weight and intake data to refine the resulting TDEE.
Related tools
Frequently asked questions
Mifflin-St Jeor is often recommended for contemporary adults, but neither equation is exact for every person. Their error can exceed the difference between their results.
BMR results are population-based estimates for informational use, not medical measurements or nutrition prescriptions. Consult a doctor or registered dietitian when illness, medication, pregnancy, growth, or eating-disorder recovery affects your energy needs.
Explore more nutrition & diet tools
Pair this calculator with related tools for a complete plan.