BEE Calculator (Basal Energy Expenditure)

Quick answer

The BEE calculator estimates basal energy expenditure with the original Harris–Benedict equation used in clinical nutrition, and multiplies it by activity and stress (injury) factors to estimate a patient's total energy needs.

years
Basal energy expenditure
1,786 kcal/day
Estimated total energy needs
2,143 kcal/day
Energy per kg
28.6 kcal/kg

In hospitals, BEE is adjusted for activity (bed rest, out of bed) and for metabolic stress from surgery, infection, trauma or burns, which can raise energy needs by up to 100%.

How to use the BEE Calculator

  1. Sex
  2. Age
  3. Weight
  4. Height
  5. Activity factor
  6. Stress factor

Results update as you type, and every field accepts the units shown in its menu.

How it works

Enter the patient’s sex, age, weight and height, then choose activity and stress factors. The calculator multiplies BEE by both.

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
Activity factor Choose one: Confined to bed (1.2), Out of bed (1.3), Active (1.5)
Stress factor Choose one: None (1.0), Minor surgery (1.1), Infection (1.2), Major surgery or trauma (1.35) …

What each result means

  • Estimated total energy needs = [Basal energy expenditure]×[Activity factor]×[Stress factor]
  • Energy per kg = [Estimated total energy needs]÷[Weight]

Example values

How the main result changes when Age changes and everything else stays at the example values above:

Age (years) Basal energy expenditure (kcal/day)
15 1,887
22.5 1,836
30 1,786
37.5 1,735
45 1,684
60 1,583

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: BEE = 66.5 + 13.75W + 5.003H − 6.755A Women: BEE = 655.1 + 9.563W + 1.850H − 4.676A Total needs = BEE × activity factor × stress factor

Worked example

Inputs — Sex: Male; Age: 30 years; Weight: 75 kg; Height: 178 cm; Activity factor: Confined to bed (1.2); Stress factor: None (1.0).
Results — Basal energy expenditure = 1,786 kcal/day; Estimated total energy needs = 2,143 kcal/day; Energy per kg = 28.6 kcal/kg.

Key terms

Stress factor
Multiplier for the increase in metabolism caused by illness or injury.

Frequently asked questions

What is the difference between BEE and BMR?

They mean the same thing; BEE is the term used with Harris–Benedict in clinical settings.

Why add a stress factor?

Illness, surgery and burns raise metabolic rate.

Is indirect calorimetry better?

Yes – it measures energy use directly and is preferred in intensive care.

Sources

  1. Harris JA, Benedict FG. A biometric study of human basal metabolism. PNAS, 1918
  2. Long CL et al. Metabolic response to injury and illness. JPEN, 1979

Cite this calculator

Speedy Calculator. (2026). BEE Calculator (Basal Energy Expenditure). Speedy Calculator. https://speedycalculator.com/calculators/health/bee/