BMR Calculator
Free BMR calculator using the Mifflin-St Jeor equation. Estimate the calories your body burns at rest and your daily needs at every activity level.
Your Details
Basal Metabolic Rate
1,649 kcal
Daily Calories by Activity
How It Works
Choose units and gender
Pick metric or imperial units, then select your biological sex, which changes the equation constant.
Enter age, height and weight
Type your age, height and weight. Results recalculate instantly as you change any value.
Review your BMR and daily needs
See your basal metabolic rate plus estimated daily calories for five activity levels.
Your Basal Metabolic Rate is the energy your body spends just to stay alive while at complete rest — powering your heart, lungs, brain and other organs. It typically accounts for 60 to 70 percent of the calories you burn in a day, which is why knowing it is the starting point for any nutrition or weight plan.
This calculator uses the Mifflin-St Jeor equation, the formula most dietitians prefer for healthy adults. It then multiplies your BMR by standard activity factors to estimate your total daily calorie burn, so you can see roughly how much you need to eat to maintain your weight at different activity levels.
Frequently Asked Questions
What is BMR?
Basal Metabolic Rate (BMR) is the number of calories your body uses at complete rest to keep essential functions running — breathing, circulation, cell production and temperature regulation. It is the largest part of most people’s daily calorie burn.
Which formula does this use?
It uses the Mifflin-St Jeor equation, widely regarded as one of the most accurate for healthy adults: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5 for men, or − 161 for women.
How do I turn BMR into daily calories?
Multiply BMR by an activity factor: about 1.2 if sedentary, 1.375 lightly active, 1.55 moderately active, 1.725 very active and 1.9 if extremely active. This calculator shows all five so you can pick the closest match.
How accurate is this estimate?
The Mifflin-St Jeor equation is an estimate based on population averages and does not account for individual differences in body composition, genetics or hormones. Results are for general information only and are not medical advice — consult a professional before making big dietary changes.
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