Calculate your basal metabolic rate and preview daily calories by activity level.
The Mifflin-St Jeor equation estimates the calories your body burns at complete rest from your weight, height, age and sex.
Multiply BMR by an activity factor (1.2 sedentary to 1.9 very active) to estimate your total daily energy expenditure (TDEE).
BMR is what you burn at rest; TDEE adds the calories burned through daily activity and exercise.
It is the most accurate of the common predictive equations for modern populations, validated against indirect calorimetry.
No. It is an estimate; only indirect calorimetry measures your actual metabolic rate.
This calculator estimates your Basal Metabolic Rate (BMR) — the number of kilocalories your body needs at complete rest to maintain basic functions such as breathing, circulation and cell repair. Enter your sex, age, weight and height to see your resting energy estimate and a preview of total daily needs at five activity levels.
The headline figure is your estimated BMR in kilocalories per day. Below it, the activity-level table shows your estimated Total Daily Energy Expenditure (TDEE) — BMR multiplied by a standard activity factor — from sedentary (desk work, little movement) up to very active (intense training most days). These are population-average estimates; individual metabolism varies.
A 30-year-old male, 80 kg and 180 cm tall, entered with metric units.
Estimated BMR is 1,780 kcal/day. At a moderate activity level (exercise 3–5 days per week) the estimated TDEE is approximately 2,759 kcal/day.
BMR (Basal Metabolic Rate) is an estimate of the energy your body burns while completely at rest — covering heart beat, breathing, temperature regulation and other involuntary functions. It does not include calories burned through physical activity or digestion.
It uses the Mifflin-St Jeor equation (1990), which research has shown to be the most accurate of the common predictive equations for most adults. For men the formula is 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5; for women −161 replaces the +5.
Predictive equations like Mifflin-St Jeor typically estimate BMR within 10–15% of the value measured by indirect calorimetry. Body composition, genetics and health conditions all affect the true figure. Treat the result as an informational estimate, not a clinical measurement.
BMR is the energy required at rest only. TDEE (Total Daily Energy Expenditure) adds the calories burned through physical activity and the thermic effect of food. The activity-level table provides a rough TDEE estimate for planning purposes.
This calculator is informational only and does not provide dietary advice. Eating at or below BMR for extended periods is generally not recommended without medical supervision. Consult a registered dietitian or healthcare provider for personalised nutrition guidance.
The calculator applies the Mifflin-St Jeor equation, published in the American Journal of Clinical Nutrition in 1990 (PMID 2305711). The formula is: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age(years) + 5 for men, and the same expression minus 161 for women. The sex offset accounts for average differences in lean body mass. BMR represents resting energy expenditure only — the calories needed to sustain vital functions at rest. To estimate total daily energy expenditure (TDEE), the result is multiplied by a standard activity factor: 1.2 for sedentary, 1.375 for light activity, 1.55 for moderate, 1.725 for active and 1.9 for very active. These multipliers are conventional population averages and not individually calibrated.
Spot a translation issue, a calculation issue, or have a suggestion? Let us know.