# BEE Calculator (Basal Energy Expenditure)

URL: https://speedycalculator.com/calculators/health/bee/
Last updated: 2026-10-30

> 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.

## Inputs

- Sex
- Age (years)
- Weight (kg, lb, st, g)
- Height (cm, in, m, ft, mm)
- Activity factor
- Stress factor

## Results

- Basal energy expenditure
- Estimated total energy needs
- Energy per kg

## 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
```

## Explanation

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

- **Sex**
- **Age**
- **Weight**
- **Height**
- **Activity factor**
- **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

FieldWhat to enterSexChoose one: Male, FemaleAgeIn yearsWeightUnits: kg, lb, st, gHeightUnits: cm, in, m, ft, mmActivity factorChoose one: Confined to bed (1.2), Out of bed (1.3), Active (1.5)Stress factorChoose 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)151,88722.51,836301,78637.51,735451,684601,583
*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.*

## 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.

## FAQ

**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

- [Harris JA, Benedict FG. A biometric study of human basal metabolism. PNAS, 1918](https://pubmed.ncbi.nlm.nih.gov/16576330/)
- [Long CL et al. Metabolic response to injury and illness. JPEN, 1979](https://pubmed.ncbi.nlm.nih.gov/575168/)