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🔥 Health Last tested2026-05-25

BMR Calculator in seconds.

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Quick answer

A 30-year-old woman, 165 cm, 65 kg has a BMR of about 1,430 kcal/day — meaning her body burns that many calories just to keep organs functioning at rest.

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BMR Calculator

Basal Metabolic Rate
1,699kcal/day

Calories your body burns at complete rest — organs, breathing, circulation.

Daily calorie needs by activity level
Sedentary
Little or no exercise · ×1.2
2,039kcal
Lightly Active
Exercise 1–3 days/week · ×1.375
2,336kcal
Moderately Active
Exercise 3–5 days/week · ×1.55
2,633kcal
Very Active
Hard exercise 6–7 days/week · ×1.725
2,930kcal
Extra Active
Very hard exercise / physical job · ×1.9
3,228kcal
✨ Live · Mifflin-St Jeor Equation · For educational use only — consult a dietitian for personal advice
PN
Reviewed by
Priya Nair, RD, MSc Nutrition LinkedIn ↗

RD with 9+ years in clinical nutrition & metabolism.

📖 How to use

3 inputs. Instant result.

1

Select your biological sex and choose metric or imperial units

2

Enter your age, height, and current weight using the fields or sliders

3

See your BMR instantly — plus a breakdown of daily calorie needs by activity level

🧮 The formula

Mifflin-St Jeor Equation.

For Men
BMR = (10 × kg) + (6.25 × cm) − (5 × age) + 5
For Women
BMR = (10 × kg) + (6.25 × cm) − (5 × age) − 161

Imperial inputs are automatically converted: 1 lb = 0.453592 kg · 1 inch = 2.54 cm. Results are identical regardless of unit system.

Your Basal Metabolic Rate is the number of calories your body burns at complete rest — no movement, no digestion, no activity. It represents 60–75% of total daily calorie expenditure for most sedentary people. The Mifflin-St Jeor equation is the most widely validated formula for estimating BMR in healthy adults.

BMR declines naturally with age (roughly 1–2% per decade after 20), mainly due to loss of muscle mass. Increasing lean muscle through resistance training is one of the most effective ways to counteract this decline and keep metabolic rate higher.

Use the activity multiplier table in the calculator above to find your TDEE — the actual calories you need each day accounting for your lifestyle. Sedentary office workers typically land at 1.2–1.375× BMR, while athletes can reach 1.7–1.9×.

Sources: Mifflin MD et al. (1990), Am J Clin Nutr · Institute of Medicine Dietary Reference Intakes

❓ FAQ

Common questions.

What is BMR?
Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest — the minimum energy needed to keep your heart beating, lungs breathing, and organs functioning. It excludes any activity, digestion, or movement.
Which formula does this BMR calculator use?
This calculator uses the Mifflin-St Jeor Equation (1990), the most accurate formula for most adults according to the American Dietetic Association. Men: BMR = (10 × kg) + (6.25 × cm) − (5 × age) + 5. Women: BMR = (10 × kg) + (6.25 × cm) − (5 × age) − 161.
What is a normal BMR for a woman?
For a 30-year-old woman at 165 cm and 65 kg, BMR is about 1,430 kcal/day. Most adult women range between 1,200 and 1,700 kcal/day depending on body size and age. BMR decreases roughly 1–2% per decade after age 20.
How is BMR different from TDEE?
BMR is your calorie burn at absolute rest. TDEE (Total Daily Energy Expenditure) multiplies BMR by an activity factor — sedentary people multiply by 1.2, very active people by 1.725. Your actual daily calorie need is your TDEE, not your BMR.
Can I eat fewer calories than my BMR?
Consistently eating below BMR is not recommended. It can cause muscle loss, nutrient deficiencies, and metabolic adaptation. BMR is the floor — a hard minimum just to sustain organ function. Most dietitians recommend staying above 1,200 kcal/day for women and 1,500 kcal/day for men.
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