🔥 BMR Calculator
Estimate your Basal Metabolic Rate (BMR) — the calories your body burns at complete rest — using the Mifflin-St Jeor equation, the formula most dietitians consider the most accurate for modern populations.
The Mifflin-St Jeor equation
Published in 1990, this is the resting-energy equation most dietitians reach for because it fits modern populations better than the older Harris-Benedict. Sex changes only the constant on the end:
BMR = (10 × kg) + (6.25 × cm) - (5 × age) + 5 (male)
BMR = (10 × kg) + (6.25 × cm) - (5 × age) - 161 (female)A 30-year-old man at 170 cm and 70 kg: 700 + 1062.5 - 150 + 5 = 1618 kcal a day. A woman with the same numbers gets 1452. Imperial entries convert at 2.54 cm per inch and 0.453592 kg per pound.
BMR is not what you eat
BMR is what you would burn lying still all day, so the tool also multiplies it by activity factors: sedentary ×1.2, lightly active ×1.375, moderately active ×1.55, very active ×1.725. Our 1618 kcal man lands on 1941 sedentary, 2507 moderately active.
Pick the honest row. Most people overrate their activity by a step, which is worth 200-300 kcal a day - enough to stall a deficit.
Frequently asked questions
What is the difference between BMR and TDEE?
BMR is rest only. TDEE is BMR times an activity factor, so it includes exercise, walking and digesting food. The rows under your BMR here are TDEE estimates.
Why does BMR fall as you get older?
The equation subtracts 5 kcal per year of age, so 20 years costs 100 kcal a day. That stands in for the muscle most people lose over time rather than anything about age itself.
Should I eat below my BMR to lose weight?
Rarely necessary - a deficit is measured against your TDEE, not your BMR. Very low intakes are hard to hold and cost muscle. Talk to a doctor or dietitian before going there.