Mifflin-St Jeor BMR Calculator (Gold Standard)
Calculate your Basal Metabolic Rate using the most accurate scientifically validated formula. Includes a comparison against Harris-Benedict and Katch-McArdle.
About
In the world of metabolic science, accuracy is paramount. The Mifflin-St Jeor equation, introduced in 1990, is widely considered by dietitians and clinical health professionals to be the most reliable formula for estimating Basal Metabolic Rate (BMR) in modern populations. While older formulas like Harris-Benedict (1919) were groundbreaking, they tend to overestimate calorie needs in today's more sedentary and overweight population.
This tool not only calculates your BMR using the specific Mifflin-St Jeor coefficients but also provides a comparative analysis. By seeing how this result differs from other equations, you can better understand the potential margin of error and choose a caloric baseline that aligns with your weight management goals.
Formulas
The equation uses separate constants for men and women. The variables are Weight (W, kg), Height (H, cm), and Age (A, years).
For Men:
For Women:
Reference Data
| Formula | Origin Year | Tendency | Best For... |
|---|---|---|---|
| Mifflin-St Jeor | 1990 | Most Accurate | General Population (Modern) |
| Harris-Benedict (Orig) | 1919 | Overestimates (+5-15%) | Historical Reference |
| Harris-Benedict (Rev) | 1984 | Slight Overestimate | Active Individuals |
| Katch-McArdle | 1980s | Lean Mass Based | Athletes (Requires Body Fat %) |
| Activity Factor | Multiplier | Description | Example |
| Sedentary | 1.2 | Little/no exercise | Desk job |
| Lightly Active | 1.375 | Light exercise 1-3 days/wk | Walking, Yoga |
| Moderately Active | 1.55 | Moderate 3-5 days/wk | Gym, Jogging |
| Very Active | 1.725 | Hard exercise 6-7 days/wk | Sports, Labor |
| Extra Active | 1.9 | Very hard/physical job | Marathon training |