BMR calculator
Estimate your Basal Metabolic Rate (BMR) — the calories your body burns at complete rest, before any activity.
Fill in the fields and press Calculate to see your result here.
How this calculation works
The Mifflin-St Jeor equation estimates BMR from weight, height, age and sex. For men it's 10 × kg + 6.25 × cm − 5 × age + 5; for women it's the same calculation − 161 instead of + 5. It is widely regarded as one of the more accurate formulas for the general population, though it is still an estimate rather than a direct measurement.
Worked example
A 30-year-old man weighing 80 kg at 180 cm: 10 × 80 + 6.25 × 180 − 5 × 30 + 5 = 800 + 1125 − 150 + 5 = 1,780 kcal/day. That's the energy his body burns at complete rest, before any activity is added.
Health note: This is a general estimate for information only and is not medical advice. Speak with a doctor or registered dietitian before changing how much you eat.
Tips
BMR excludes activity
This is the energy your body needs simply to keep functioning — breathing, circulation, cell repair. For a figure that includes exercise and movement, use the calorie calculator instead.
BMR changes with your body
Weight, height and age all feed the formula, so your figure moves over time. The age term reflects a gradual decline in resting energy use.
Not a daily eating target
BMR is the energy for basic functions at rest. Eating far below it for long periods is generally not advised without medical supervision.
Pair it with activity
For a full-day estimate that includes movement, use the Calorie calculator, which multiplies BMR by an activity factor.
Frequently asked questions
How is BMR different from TDEE?
BMR is calories at complete rest; TDEE adds your daily activity on top of BMR. Use the calorie calculator for a TDEE estimate.
Why does BMR decrease with age?
The formula reduces BMR slightly for each year of age, reflecting the gradual, typical decline in resting metabolic rate as people get older.