Health

BMR & Calorie Calculator

Calculate your basal metabolic rate and daily maintenance calories based on your activity level.

Reviewed & Maintained by

Aadil Malik — Software Engineer

1 min read · 162 words

What is a BMR Calculator?

A Basal Metabolic Rate (BMR) calculator determines the minimum energy expenditure required to sustain vital organ functions at complete physical and digestive rest.

The Mifflin-St Jeor BMR Equations

For Men: $$\text{BMR} = 10 \times \text{weight (kg)} + 6.25 \times \text{height (cm)} - 5 \times \text{age (years)} + 5$$

For Women: $$\text{BMR} = 10 \times \text{weight (kg)} + 6.25 \times \text{height (cm)} - 5 \times \text{age (years)} - 161$$

Activity Multipliers (Calculating TDEE)

$$\text{TDEE} = \text{BMR} \times \text{Activity Factor}$$

Activity Level	Multiplier	Description
Sedentary	$1.200$	Desk job, little to no exercise
Lightly Active	$1.375$	Light exercise 1–3 days/week
Moderately Active	$1.550$	Moderate exercise 3–5 days/week
Very Active	$1.725$	Hard exercise 6–7 days/week
Extra Active	$1.900$	Heavy physical labor or athlete training

Frequently Asked Questions

BMR is the baseline number of calories your body burns at rest to maintain essential vital functions like breathing, circulation, cellular repair, and brain activity.

BMR is resting caloric expenditure. Total Daily Energy Expenditure (TDEE) is BMR multiplied by your physical activity factor, representing your true daily maintenance calories.

The Mifflin-St Jeor equation is considered the most clinically accurate formula by the Academy of Nutrition and Dietetics.

To lose approximately 1 lb (0.45 kg) of fat per week, subtract 500 calories from your daily TDEE (creating a 3,500 kcal weekly deficit).

Yes. Prolonged aggressive caloric deficits cause non-resting energy expenditure and thyroid hormones to down-regulate slightly. Periodic diet breaks and resistance training preserve metabolic rate.

Yes. Skeletal muscle is metabolically active tissue, burning approximately 3x more calories at rest per pound than adipose fat tissue.

BMR typically decreases by 1%–2% per decade after age 30, largely due to age-related loss of lean muscle mass (sarcopenia).

Unless under clinical medical supervision, daily caloric intake should not drop below 1,200 kcal/day for women or 1,500 kcal/day for men.