Basal Metabolic Rate (Harris–Benedict)

What is this formula?

The Harris–Benedict equation estimates Basal Metabolic Rate (BMR), which represents the amount of energy the body requires each day at complete rest to maintain essential physiological functions such as breathing, circulation, cellular activity, and temperature regulation.

When to use it

Use this formula when estimating daily caloric requirements, planning nutrition programs, designing weight management strategies, or calculating total daily energy expenditure.

Example

A 30-year-old man weighs 80 kg and is 180 cm tall.

Data:

W = 80 kg

H = 180 cm

A = 30 years

Formula:

BMR = 88.362 + 13.397W + 4.799H − 5.677A

Substitution:

BMR = 88.362 + (13.397×80) + (4.799×180) − (5.677×30)

BMR = 1853.6 kcal/day

Result:

Basal metabolic rate ≈ 1854 kcal/day

Applications

- Nutrition planning

- Diet formulation

- Weight loss programs

- Sports science

- Clinical nutrition

- Metabolic assessment

- Fitness coaching

Note

The Harris–Benedict equation is an empirical model derived from population studies. It provides an estimate rather than a direct measurement of metabolic rate. Accuracy may decrease in highly muscular individuals, people with severe obesity, elderly populations, or certain medical conditions. Modern alternatives such as the Mifflin–St Jeor equation are often preferred in contemporary clinical nutrition.