Key Takeaways
- The Mifflin-St Jeor equation (1990) is considered the most accurate general-purpose REE prediction equation, recommended by the American Dietetic Association.[1]
- It tends to be ~5% more accurate than the Harris-Benedict equation, which systematically overestimates metabolic rate in modern populations.[2]
- TDEE is calculated by multiplying REE by an activity factor. Goal-based targets apply calorie surpluses or deficits from TDEE.
- For a multi-formula comparison, use the REE Calculator which includes Mifflin-St Jeor, Harris-Benedict, Cunningham, and WHO/FAO/UNU.
About the Mifflin-St Jeor Equation
Published in 1990 by MD Mifflin and ST St Jeor, this equation was derived from a study of 498 healthy adults (251 women, 247 men). It uses weight in kilograms, height in centimeters, and age in years.[1]
Males: REE = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
Females: REE = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
Unlike the Harris-Benedict equation (see the Harris-Benedict Calculator), Mifflin-St Jeor was developed on a more recent and diverse sample, making it more representative of contemporary populations.
Activity Multipliers Explained
| Level | Multiplier | Example |
|---|---|---|
| Sedentary | 1.2 | Desk job, no structured exercise |
| Lightly Active | 1.375 | Light exercise 1–3 days/week |
| Moderately Active | 1.55 | Moderate exercise 3–5 days/week |
| Very Active | 1.725 | Hard exercise 6–7 days/week |
| Extra Active | 1.9 | Athlete or physical labor job |
For a detailed daily energy breakdown, see the AMR Calculator.
Limitations
- Mifflin-St Jeor does not account for body composition — individuals with high lean mass may have higher actual REE than predicted.
- Activity multipliers are broad categories and may not precisely match your activity pattern.
- The equation was validated primarily in North American and European populations aged 19–78.
- For athletes with known body fat %, the Cunningham equation (available in the RMR Calculator) may be more appropriate.
- This tool is for informational and journaling purposes only. It does not constitute personalized advice.
Frequently Asked Questions
Sources & References
- A new predictive equation for resting energy expenditure in healthy individuals. Mifflin MD, St Jeor ST, et al.. Am J Clin Nutr (1990)
- Comparison of predictive equations for resting metabolic rate. Frankenfield D, et al.. J Am Diet Assoc (2005)
- Validity of predictive equations for resting energy expenditure. Various. ResearchGate (2023)
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This tool is for informational and journaling purposes only.
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