Press ESC to close

Harris and Benedict Calculator

Estimate your basal metabolic rate using the scientifically validated Harris and Benedict equation.

Harris and Benedict Calculator

The Harris and Benedict equation is one of the most established scientific formulas for estimating basal metabolic rate (BMR). Your BMR represents the number of calories your body requires at rest to maintain essential physiological functions such as breathing, circulation, and cellular repair.

Understanding your metabolic baseline is a key step in optimizing nutrition, supporting healthy aging, and improving long-term metabolic resilience. The Harris and Benedict calculator helps translate personal data—age, sex, height, and weight—into actionable insights for preventive health and longevity planning.

Harris–Benedict BMR Calculator

Calculate your Basal Metabolic Rate and Total Daily Energy Expenditure using the original (1919) or revised (Roza & Shizgal, 1984) Harris–Benedict equation.

Your Profile (Step 1 of 3)
⚙

Your Profile

Enter your biological sex, age, height and weight. These four variables are the inputs to both versions of the Harris–Benedict equation.

♂
Male
♀
Female
Valid range: 18–120 years.
Please enter an age between 18 and 120.
Please enter a height between 100 and 250 cm.
Please enter a weight between 20 and 500 kg.
--
Estimated BMR (kcal / day)
📈

Equation & Activity Level

Choose which version of the Harris–Benedict equation to use, then select your daily activity level to calculate your Total Daily Energy Expenditure (TDEE).

Original (1919)
Harris & Benedict — PNAS 1919. Published by the Carnegie Institution of Washington. Based on 239 subjects.
Historic
Revised (1984)
Roza & Shizgal — Am J Clin Nutr 1984. Recalculated on 337 subjects. Stronger R² (0.77 / 0.68).
More Accurate
Activity multipliers per Harris & Benedict (1919) as popularised by McArdle, Katch & Katch, Exercise Physiology (2010).

Basal Metabolic Rate (BMR)

--
kcal / day
--
--
Sex
--
Age
--
Height
--
Weight

Total Daily Energy Expenditure (TDEE)

--
kcal / day
--

BMR

--
kcal / day

TDEE

--
kcal / day

Activity factor

--
PAL multiplier

Equation

--
version

Step-by-step calculation

Equation used: --
Formula: --
BMR calculation: --
TDEE: BMR × activity factor
TDEE result: --

Your TDEE at every activity level

Activity level Multiplier TDEE (kcal/day) Notes

Using your TDEE for weight goals

Goal Daily calorie target Expected rate
~7,700 kcal = 1 kg body weight change (Hall KD, Obesity Reviews, 2008). Never eat below your BMR without medical supervision.

Harris–Benedict equation versions compared

Version Men Women Sample size & accuracy
Original (Harris & Benedict, 1919) 66.47 + (13.75 × kg) + (5.003 × cm) − (6.755 × age) 655.1 + (9.563 × kg) + (1.850 × cm) − (4.676 × age) n=239 (R²=0.64/0.36). Tends to overestimate by ~5%.
Revised (Roza & Shizgal, 1984) 88.362 + (13.397 × kg) + (4.799 × cm) − (5.677 × age) 447.593 + (9.247 × kg) + (3.098 × cm) − (4.330 × age) n=337 (R²=0.77/0.68). Improved accuracy over original.
Mifflin–St Jeor (1990) 10 × kg + 6.25 × cm − 5 × age + 5 10 × kg + 6.25 × cm − 5 × age − 161 n=498. Most accurate: 82% within ±10% of measured (Frankenfield et al., J Am Diet Assoc, 2005).
Medical disclaimer The Harris–Benedict equation was derived from measurements of early 20th-century Americans and may overestimate BMR by approximately 5% compared to modern populations (Harris & Benedict, PNAS, 1919; Roza & Shizgal, Am J Clin Nutr, 1984). For greater accuracy in modern populations, the Mifflin–St Jeor equation (1990) is generally recommended by the Academy of Nutrition and Dietetics (Frankenfield et al., J Am Diet Assoc, 2005). BMR calculators do not account for body composition, hormonal status, medications, or individual metabolic variation. Do not restrict calories below your BMR without medical supervision. Consult a registered dietitian or physician before making significant dietary changes.

Our other tools

ANC Calculator

ANC Calculator Calculate your Absolute Neutrophil Count to better...

Understanding Harris and Benedict

The Harris and Benedict equation was first developed in 1919 and later revised to improve accuracy. It estimates basal metabolic rate by considering biological sex, total body weight, height, and age. These variables reflect differences in lean body mass, hormonal regulation, and age-related metabolic adaptation.

Basal metabolic rate accounts for approximately 60–75% of total daily energy expenditure in most individuals. By calculating BMR using the Harris and Benedict method, you can better determine your total daily energy needs once physical activity levels are factored in. This supports structured nutrition strategies, whether the goal is weight maintenance, fat loss, muscle preservation, or metabolic optimization.

In longevity science, maintaining an appropriate energy balance is essential. Chronic overnutrition may accelerate metabolic dysfunction, while excessive caloric restriction can impair hormonal health and muscle mass. The Harris and Benedict calculator provides a practical, evidence-based starting point for aligning caloric intake with physiological requirements.

On the same subject

Longevity Tools
  • 16 Mar 2026
Fat Calculator: Accurately Estimate Your Body Fat Percentage

Understanding your body fat percentage…

Longevity Tools
  • 16 Mar 2026
Net Carb Calculator: Easily Track Your Carbohydrate Intake

Managing carbohydrates is key for…

Longevity Tools
  • 16 Mar 2026
Future Height Calculator: Estimate Your Adult Height Accurately

Wondering how tall you—or your…

Stay Informed

 Stay informed with clear, science-backed insights on longevity, nutrition and preventive health. Each week, Sogevity shares practical tools, research highlights and simple habits to help you extend your healthspan and make smarter decisions for your future.

    FAQ

    Understanding this calculator can raise questions. Here you’ll find clear, evidence-based answers to help you interpret your results and understand the science behind it.

    The Harris and Benedict equation calculates basal metabolic rate (BMR), which represents the calories your body needs at complete rest to sustain essential biological functions. It does not directly calculate total daily calorie needs unless activity levels are added afterward.

    The Harris and Benedict formula is considered reasonably accurate for population-level estimates. However, it does not directly measure body composition. Individuals with significantly higher or lower muscle mass than average may experience slight deviations from predicted values.

    Compared to newer equations such as Mifflin-St Jeor, Harris and Benedict tends to produce slightly higher calorie estimates in some populations. However, both methods are scientifically validated and widely used in clinical and nutritional settings.

    Yes. By calculating your BMR and then adjusting for activity level, you can estimate total daily energy expenditure (TDEE). Creating a moderate calorie deficit relative to that number may support gradual fat loss while preserving metabolic health and lean mass.

    The Harris and Benedict calculator provides a structured and evidence-based way to estimate your basal metabolic rate. By understanding your physiological energy requirements, you can make more informed decisions about nutrition, activity, and long-term health strategies.

    In the context of preventive medicine and longevity optimization, accurate estimation of energy needs is foundational. The Harris and Benedict equation remains a trusted scientific tool for evaluating metabolic baseline and supporting sustainable, health-focused lifestyle planning.