Mifflin and St Jeor published their equation in 1990 from measurements of 498 healthy adults. In comparisons it predicts measured resting energy expenditure within 10% for more people than older equations.
How to use the Mifflin–St Jeor Calculator
- Sex
- Age
- Weight
- Height
Results update as you type, and every field accepts the units shown in its menu.
How it works
Enter sex, age, weight and height. The equation adds the effect of weight and height, subtracts the effect of age and applies a constant for sex.
Inputs explained
| Field | What to enter |
|---|---|
| Sex | Choose one: Male, Female |
| Age | In years |
| Weight | Units: kg, lb, st, g |
| Height | Units: cm, in, m, ft, mm |
What each result means
- BMR in kilojoules = [BMR]×4.184
- Calories per hour at rest = [BMR]÷24
- Daily calories if sedentary (× 1.2) = [BMR]×1.2
- Daily calories if moderately active (× 1.55) = [BMR]×1.55
Example values
How the main result changes when Age changes and everything else stays at the example values above:
| Age (years) | BMR (kcal/day) |
|---|---|
| 15 | 1,793 |
| 22.5 | 1,755 |
| 30 | 1,718 |
| 37.5 | 1,680 |
| 45 | 1,643 |
| 60 | 1,568 |
Health note: this calculator is for education and screening only and is not a diagnosis or treatment advice. Discuss your results with a qualified clinician.
Formula
Men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
Women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
Worked example
Inputs — Sex: Male; Age: 30 years; Weight: 75 kg; Height: 178 cm.
Results — BMR = 1,718 kcal/day; BMR in kilojoules = 7,186 kJ/day; Calories per hour at rest = 71.6 kcal/h; Daily calories if sedentary (× 1.2) = 2,061 kcal/day; Daily calories if moderately active (× 1.55) = 2,662 kcal/day.
Key terms
- BMR
- Basal metabolic rate.
Frequently asked questions
Is Mifflin–St Jeor better than Harris–Benedict?
In most studies it is slightly more accurate for modern adults.
Does BMR include exercise?
No – it is the energy used at complete rest.
How can I raise my BMR?
Building muscle raises it a little; very low calorie diets lower it.
Sources
- Mifflin MD et al. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr, 1990
- Roza AM, Shizgal HM. The Harris Benedict equation reevaluated. Am J Clin Nutr, 1984
- McArdle WD, Katch FI, Katch VL. Exercise Physiology: Nutrition, Energy and Human Performance