Nutrition

BMR Calculator

Calculate your Basal Metabolic Rate — the minimum calories your body burns every day just to keep you alive, at complete rest.

BMR Calculator

Mifflin-St Jeor · Harris-Benedict

BMR (kcal / day)

BMR is the foundation of your caloric needs. Multiply it by your activity factor to get TDEE (Total Daily Energy Expenditure). Even if you did nothing all day, your body would burn this many calories keeping your organs, brain, and metabolism running.

Mifflin-St Jeor (men): 10W + 6.25H - 5A + 5. (women): 10W + 6.25H - 5A - 161.

BMR by Weight & Sex (Mifflin-St Jeor, age 30, 175cm / 5'9")

WeightMale BMR (kcal)Female BMR (kcal)
55 kg / 121 lbs~1,450~1,289
70 kg / 154 lbs~1,600~1,439
85 kg / 187 lbs~1,750~1,589
100 kg / 220 lbs~1,900~1,739
115 kg / 253 lbs~2,050~1,889

BMR vs TDEE — What's the Difference?

BMR is your resting calorie burn — the calories needed just to keep you alive. TDEE (Total Daily Energy Expenditure) is BMR multiplied by an activity factor (1.2–1.9). BMR is typically 60–70% of TDEE for most active people. A sedentary office worker multiplies BMR × 1.2; a hard-training athlete may multiply by 1.7–1.9. Use the TDEE calculator to get your full daily calorie need.

What Affects BMR?

The main factors are lean body mass, age, sex, and height. Muscle tissue is metabolically more active than fat — so two people of the same weight can have very different BMRs if one is more muscular. BMR naturally declines about 1–2% per decade from age 30, which is why maintaining muscle mass through resistance training is important as you age.

Note on formulas: Mifflin-St Jeor is generally the most accurate for average adults. Harris-Benedict (revised) is shown for comparison. If you know your body fat %, the Katch-McArdle formula using lean mass is even more precise.

Frequently Asked Questions

BMR is the foundation for calculating all calorie-based nutrition plans. Multiply it by an activity factor (1.2–1.9) to get TDEE, then add or subtract calories for bulking or cutting. Without knowing your BMR, any calorie target is just a rough guess.
For people with unknown body fat, the Mifflin-St Jeor formula (1990) is considered the most accurate for average adults — within ±10% for most people. If you know your lean body mass, the Katch-McArdle formula is even more precise because it accounts for how much metabolically active tissue you have.
Yes. BMR naturally decreases with age (roughly 1–2% per decade after 30), primarily due to age-related muscle loss (sarcopenia). Extended calorie restriction also temporarily lowers BMR as the body adapts. Resistance training and adequate protein intake are the most effective way to maintain BMR as you age.
Yes — the most effective method is building lean muscle mass through progressive resistance training. Every kg of muscle you add increases resting energy expenditure. Also: eating adequate protein has a high thermic effect (25–30% of its calories are burned through digestion), which effectively raises your total daily energy burn.