🔥 BMR Calculator — Basal Metabolic Rate

Q: How is BMR calculated?

BMR is calculated using formulas based on weight, height, age and gender. The Mifflin-St Jeor formula (recommended): Men — 10×weight(kg) + 6.25×height(cm) − 5×age + 5. Women — 10×weight(kg) + 6.25×height(cm) − 5×age − 161. The Harris-Benedict formula is an older alternative that tends to slightly overestimate BMR.

Q: What is the difference between BMR and TDEE?

BMR is the calories your body burns at complete rest. TDEE (Total Daily Energy Expenditure) is your BMR multiplied by an activity factor that accounts for how much you move each day. For most people, TDEE is 1.2× to 1.9× their BMR. Eating at your TDEE maintains your current weight.

Q: How many calories do I need to lose weight?

To lose weight, you need to eat fewer calories than your TDEE. A deficit of 500 cal/day leads to approximately 0.5 kg loss per week. A deficit of 1000 cal/day leads to approximately 1 kg loss per week. Avoid going below 1200 calories per day (women) or 1500 calories per day (men) without medical supervision.

Q: Which BMR formula is most accurate?

The Mifflin-St Jeor formula is considered the most accurate for most people and is recommended by major dietetic associations. Research shows it predicts resting metabolic rate within 10% for most individuals. The Harris-Benedict formula, developed in 1919, tends to overestimate BMR by about 5%. Our calculator defaults to Mifflin-St Jeor.

Calculate your Basal Metabolic Rate, daily calorie needs and macro targets. Free, instant, no signup.

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Weight (kg)

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Activity Level

What is Basal Metabolic Rate?

Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest — lying still, not digesting food, in a thermoneutral environment. It represents the minimum energy required to keep your vital organs functioning: your brain consumes about 20% of your BMR, your liver another 20%, your heart 9%, and your muscles and other organs share the rest.

For most adults, BMR accounts for 60–70% of total daily calorie burn. This makes it the single biggest factor in how many calories you need each day — far larger than exercise or digestion. Understanding your BMR is the foundation of any evidence-based approach to weight management.

How to Use This BMR Calculator

Select your gender (Male or Female) using the tabs at the top
Choose your preferred units — metric (kg/cm) or imperial (lbs/ft·in)
Enter your age, weight and height
Select your typical activity level from the dropdown
Results update instantly — BMR, TDEE, calorie goals and macros
Click any goal row to see the macro breakdown for that target

BMR vs TDEE — What is the Difference?

BMR is your body's energy needs at complete rest. TDEE (Total Daily Energy Expenditure) is your BMR multiplied by an activity factor that accounts for how much you move during the day. A sedentary person multiplies by 1.2, while someone with a very active lifestyle multiplies by up to 1.9.

Eating at your TDEE keeps your weight stable. Eating below it causes weight loss; eating above it causes weight gain. Most people have a TDEE between 1,600 and 3,000 calories per day depending on their size and activity level.

How Many Calories Do You Need?

Your ideal daily calories depend on your goal. A deficit of 500 cal/day leads to approximately 0.5 kg of fat loss per week — a sustainable, healthy rate. A 1,000 cal/day deficit can lead to 1 kg/week loss but should be done with care and ideally under guidance. For muscle gain, a modest surplus of 300–500 calories works best for most people who want to minimise fat gain.

Lose 0.5 kg/week: TDEE − 500 cal — sustainable for most people
Lose 1 kg/week: TDEE − 1000 cal — aggressive, monitor closely
Maintain: eat at TDEE to keep current weight stable
Gain 0.5 kg/week: TDEE + 500 cal — lean muscle gain
Gain 1 kg/week: TDEE + 1000 cal — fast bulk, expect some fat gain

Protein requirements are higher when in a calorie deficit (to preserve muscle) and during a surplus (to support muscle growth). This calculator uses research-backed protein targets for each goal phase.

Frequently Asked Questions

What is Basal Metabolic Rate (BMR)?

BMR is the number of calories your body burns at complete rest to sustain basic life functions — breathing, circulation, cell repair, body temperature regulation and organ function. It accounts for 60–70% of total daily calorie burn for most people and is the baseline around which all other calorie calculations are built.

How is BMR calculated?

BMR is calculated using equations based on weight, height, age and gender. The Mifflin-St Jeor formula (recommended): Men — 10×weight(kg) + 6.25×height(cm) − 5×age + 5. Women — 10×weight(kg) + 6.25×height(cm) − 5×age − 161. The older Harris-Benedict formula gives similar results but tends to slightly overestimate BMR, especially in overweight individuals.

What is the difference between BMR and TDEE?

BMR is what your body burns at rest. TDEE (Total Daily Energy Expenditure) is your actual daily calorie burn including all movement. TDEE = BMR × activity multiplier. The multipliers range from 1.2 (sedentary) to 1.9 (extremely active). Eating at your TDEE maintains weight; eating below it causes fat loss; eating above it causes weight gain.

How many calories do I need to lose weight?

To lose weight, eat below your TDEE. A deficit of 500 cal/day produces approximately 0.5 kg of fat loss per week — a safe and sustainable rate. A 1,000 cal/day deficit can produce 1 kg/week but should not be sustained for long periods without medical oversight. Never go below 1,200 cal/day (women) or 1,500 cal/day (men).

Which BMR formula is most accurate?

The Mifflin-St Jeor formula (1990) is the most accurate for most people and is endorsed by the Academy of Nutrition and Dietetics. Studies show it predicts resting metabolic rate within 10% for about 82% of people. The Harris-Benedict formula (1919) is less accurate, especially for overweight individuals. This calculator defaults to Mifflin-St Jeor but lets you compare both.