Estimated energy needs (Mifflin-St Jeor or Harris-Benedict)
Daily calorie needs: resting energy by Mifflin-St Jeor (or Harris-Benedict) times activity and stress factors, with the weight used and kcal/kg shown.
Inputs
4 of 8SexUsed by the equation
years
Actual (total) body weight
Equation
Activity factor
1.0 for none; about 1.1 to 1.3 for surgery or infection, higher for major burns.
×
Weight used
Patient values are shared with every calculator.
When to use
- Outpatient and ward energy estimates for adults when indirect calorimetry is not available.
Pearls and pitfalls
- The Academy of Nutrition and Dietetics evidence review found Mifflin-St Jeor the most accurate equation in healthy nonobese and obese adults (within 10% of measured in most).
- Activity and stress factors are approximations; reassess with weight trend and intake.
- Critically ill adults: ASPEN/SCCM suggest indirect calorimetry, or 25 to 30 kcal/kg/day; in obesity 11 to 14 kcal/kg actual weight (BMI 30 to 50) or 22 to 25 kcal/kg ideal weight (BMI over 50).
Why use
Shows both equations, the weight used and kcal/kg so the estimate can be checked against a kcal/kg range.
Mifflin-St Jeor: 10 × kg + 6.25 × cm − 5 × age + 5 (male) or − 161 (female). Harris-Benedict: 66.47 + 13.75 kg + 5.003 cm − 6.755 age (male); 655.1 + 9.563 kg + 1.850 cm − 4.676 age (female). Needs = resting energy × activity × stress