BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest — the minimum energy needed to keep organs functioning, breathe, and circulate blood.

What is the difference between BMR and TDEE?

BMR is your resting calorie burn. TDEE is your BMR multiplied by your activity level — what you actually burn in a typical day including movement and exercise.

Can you increase your BMR?

Yes. The most effective method is building muscle mass through resistance training — muscle burns roughly 3 times more calories at rest than fat tissue.

BMR Calculator — Find Your Basal Metabolic Rate

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Biological sex

Age

Weight (kg)

Height (cm)

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Your BMR is — kcal/day

Basal metabolic rate

—kcal/day

Calories burned at complete rest

—

kcal/hour

Estimated TDEE

—kcal

At moderate activity

BMR as % of TDEE

—%

Rest vs movement split

What this means for you

TDEE at each activity level

Sedentary (× 1.2)—

Lightly active (× 1.375)—

Moderately active (× 1.55)—

Very active (× 1.725)—

Extra active (× 1.9)—

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Get your full TDEE with activity level →

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What is BMR?

Your Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest — breathing, circulating blood, maintaining organ function, and regulating body temperature. It represents the minimum energy your body needs to stay alive for 24 hours without any movement.

BMR typically accounts for 60–75% of your total daily calorie expenditure, making it by far the largest component of your energy needs. Even people who exercise intensely every day burn more calories through resting metabolism than through deliberate training. Understanding your BMR is the foundation of any calorie plan — without it, every target you set is a guess.

🔬 This calculator uses the Mifflin-St Jeor equation — validated in a 2005 peer-reviewed meta-analysis as the most accurate BMR formula for the general population. View source →

The Mifflin-St Jeor formula

The Mifflin-St Jeor equation, published in 1990, is the gold standard for BMR estimation in clinical nutrition and is used by the majority of registered dietitians worldwide.

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

Weight has the strongest influence — heavier bodies require more energy to maintain. Height contributes positively, age negatively. Women have a lower BMR than men of the same size primarily because of differences in average muscle mass, not a fundamental metabolic difference. The same man carrying more muscle will have a higher BMR than if he carried more fat at the same weight.

BMR by weight — men

These figures use the Mifflin-St Jeor equation for a 35-year-old man at 175cm. Use the BMR calculator above for your exact values.

BMR by weight — men, 35 years, 175cm

Weight	BMR	Sedentary TDEE	Moderate TDEE
60 kg	1,594 kcal	1,913 kcal	2,471 kcal
70 kg	1,694 kcal	2,033 kcal	2,626 kcal
80 kg	1,794 kcal	2,153 kcal	2,781 kcal
90 kg	1,894 kcal	2,273 kcal	2,936 kcal
100 kg	1,994 kcal	2,393 kcal	3,091 kcal
110 kg	2,094 kcal	2,513 kcal	3,246 kcal

BMR by weight — women

These figures use the Mifflin-St Jeor equation for a 35-year-old woman at 165cm.

BMR by weight — women, 35 years, 165cm

Weight	BMR	Sedentary TDEE	Moderate TDEE
50 kg	1,214 kcal	1,457 kcal	1,882 kcal
60 kg	1,314 kcal	1,577 kcal	2,037 kcal
70 kg	1,414 kcal	1,697 kcal	2,192 kcal
80 kg	1,514 kcal	1,817 kcal	2,347 kcal
90 kg	1,614 kcal	1,937 kcal	2,502 kcal
100 kg	1,714 kcal	2,057 kcal	2,657 kcal

BMR by age

BMR declines with age — primarily because of muscle loss, not because metabolism fundamentally slows. The table below shows average BMR for a man (80kg, 175cm) and woman (65kg, 165cm) at each decade. For a full breakdown by decade including TDEE ranges, read our article on average TDEE by age.

BMR by age — average adult (Mifflin-St Jeor)

Age	Man (80kg, 175cm)	Woman (65kg, 165cm)
25	1,894 kcal	1,444 kcal
30	1,844 kcal	1,394 kcal
35	1,794 kcal	1,344 kcal
40	1,744 kcal	1,294 kcal
45	1,694 kcal	1,244 kcal
50	1,644 kcal	1,194 kcal
55	1,594 kcal	1,144 kcal
60	1,544 kcal	1,094 kcal

BMR formula comparison — Mifflin-St Jeor vs Harris-Benedict

Two formulas dominate BMR calculation. The Mifflin-St Jeor (1990) is more accurate for modern populations. The Harris-Benedict (revised 1984) was the clinical standard for decades and is still used in some medical contexts.

Formula comparison — man, 35 years, 80kg, 175cm

Formula	BMR result	Notes
Mifflin-St Jeor (1990)	1,794 kcal	Most accurate for general population
Harris-Benedict revised (1984)	1,871 kcal	Tends to overestimate slightly
Katch-McArdle	Requires body fat %	Most accurate for athletic builds

The Katch-McArdle formula uses lean body mass rather than total weight — making it theoretically more accurate for muscular individuals whose fat-free mass drives their BMR. If you know your body fat percentage, use the body fat calculator to find your lean mass, then you can apply the Katch-McArdle formula: BMR = 370 + (21.6 × lean mass in kg).

BMR vs TDEE — what is the difference?

BMR is your resting baseline. TDEE (Total Daily Energy Expenditure) is your BMR multiplied by an activity factor — it accounts for all movement, digestion, and exercise. For most adults, TDEE runs 20–90% higher than BMR depending on activity level.

From BMR to TDEE — activity multipliers

Activity level	Multiplier	Example	TDEE (1,794 BMR)
Sedentary	× 1.2	Desk job, no exercise	2,153 kcal
Lightly active	× 1.375	Exercise 1–3 days/week	2,467 kcal
Moderately active	× 1.55	Exercise 3–5 days/week	2,781 kcal
Very active	× 1.725	Hard exercise 6–7 days/week	3,094 kcal
Extra active	× 1.9	Physical job + daily training	3,409 kcal

Use your BMR as a reference point and your TDEE as your actual calorie planning number. Never plan your diet around BMR — it is the floor, not the target.

How to use your BMR for weight loss

BMR alone does not tell you how much to eat — TDEE does. But BMR is an important safety check: your daily calorie intake should never drop below your BMR for extended periods. Eating at or below BMR forces your body to cannibilise muscle and organ tissue for energy, reduces your BMR further through metabolic adaptation, and causes fatigue, hormonal disruption, and nutrient deficiency.

The correct approach: calculate your TDEE, then subtract a moderate deficit of 300–500 kcal. Use the calorie deficit calculator to see exactly how long that deficit will take to reach your goal weight. Protein intake of 1.6–2.2g per kg of bodyweight throughout the deficit preserves lean mass and keeps your BMR from declining.

What is a good BMR?

There is no single "good" BMR — it depends entirely on your body size. A BMR of 1,400 kcal is completely normal for a small 50-year-old woman; the same figure would be low for a 30-year-old man of average height. What matters is whether your BMR is appropriate for your height, weight, age, and sex — not how it compares to a population average.

If your calculated BMR seems significantly lower than the table above suggests for your profile, it may indicate low muscle mass, thyroid issues, or extended periods of under-eating that have suppressed your metabolism. A registered dietitian can help investigate if you suspect this is the case.

Can you raise your BMR?

Yes — and this is one of the most overlooked aspects of long-term weight management. Your BMR is not fixed. The primary driver is muscle mass. Muscle tissue burns roughly 13 kcal per kg per day at rest, compared to roughly 4.5 kcal per kg for fat. Adding 5kg of muscle raises your BMR by approximately 42 kcal/day — not dramatic in isolation, but meaningful over years and significantly easier to maintain than permanent calorie restriction.

Resistance training two to three times per week is the most effective method. It both builds muscle and temporarily elevates metabolic rate for hours after exercise through excess post-exercise oxygen consumption (EPOC). For the protein intake that supports muscle growth, read our guide to hitting your protein target every day.

Crash dieting does the opposite — severe calorie restriction triggers metabolic adaptation, reducing BMR by 10–15% within weeks. This is why people who yo-yo diet find it progressively harder to lose weight over time.

Frequently asked questions

What is a normal BMR for a woman?

For most adult women, BMR falls between 1,200 and 1,600 kcal/day. A petite, older, or sedentary woman may sit toward the lower end; a taller, younger, or more muscular woman toward the higher end. Use the BMR calculator above with your specific measurements for an accurate figure rather than relying on averages.

What is a normal BMR for a man?

For most adult men, BMR falls between 1,500 and 2,100 kcal/day. A smaller or older man will be toward the lower end; a taller, heavier, or more muscular man toward the upper end. The table above shows BMR by weight for a 35-year-old man at average height.

Should I eat at my BMR?

No. BMR is your resting minimum — the floor, not the target. Eating at BMR means eating below your TDEE, which creates a deficit even before accounting for any movement. Long-term eating at BMR risks muscle loss, metabolic adaptation, and nutrient deficiency. Plan your intake relative to your TDEE, with a moderate deficit if fat loss is the goal.

Why does BMR decrease with age?

Primarily because of muscle loss. Adults lose roughly 3–5% of muscle mass per decade after 30 without resistance training — a process called sarcopenia. Since muscle burns more calories at rest than fat, less muscle means a lower BMR. Resistance training largely prevents this decline. See our article on average TDEE by age for decade-by-decade data.

How accurate is the Mifflin-St Jeor equation?

Accurate to within 10% for the majority of adults. It outperforms the older Harris-Benedict equation and is the most widely used formula in clinical nutrition. It is less accurate at the extremes of body composition — very muscular athletes will have a higher true BMR than the formula predicts, and people with very high body fat may have a lower one.

Does metabolism slow on a diet?

Yes — this is called metabolic adaptation. When calorie intake drops significantly below TDEE for extended periods, the body reduces BMR as a survival response, sometimes by 10–15%. Eating in a moderate deficit of 300–500 kcal rather than a severe one minimises this. Maintaining protein intake and resistance training during a deficit also significantly reduces the degree of adaptation.

What is the difference between BMR and RMR?

BMR is measured under strict clinical conditions — lying still, after an overnight fast, in a temperature-controlled environment. RMR (Resting Metabolic Rate) is measured under relaxed conditions and is typically 10–20% higher than true BMR. Most online calculators — including this one — technically calculate RMR but label it BMR. For practical diet planning this distinction does not matter. Read our full BMR vs RMR explainer for more detail.

What does your body burn at rest?