Estimate your basal metabolic rate and daily calorie needs with the Mifflin-St Jeor equation, with a weight loss or gain target.
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Enter the values to see the result here.
For general information, not medical advice. Talk to a doctor before making health decisions.
Formula
Mifflin-St Jeor for resting energy in kcal per day, with weight w in kg, height h in cm and age a in years:
BMR=10w+6.25h−5a+s,s=+5(male),−161(female)
Daily need is TDEE=BMR×f with f equal to 1.2, 1.375, 1.55, 1.725 or 1.9 from sedentary to very active. A weight target adds or subtracts calories: −500 for about −0.5 kg a week, +250 for about +0.25 kg a week.
Worked example
A 30-year-old man, 80 kg, 180 cm, exercising 3 to 5 days a week (factor 1.55).
BMR=800+1125−150+5=1,780 kcal.
TDEE=1,780×1.55=2,759 kcal.
Aiming to lose weight: 2,759−500=2,259 kcal a day.
A 25-year-old woman, 60 kg, 165 cm, has a BMR of 600+1031.25−125−161=1,345 kcal.
Common mistakes
Eating at the BMR figure. That is only resting need and leaves out all activity.
Picking “very active” for a gym habit of three sessions a week.
Trusting the target to the calorie. The equation has an error of roughly 10% for individuals.
Dropping below about 1,200 kcal (women) or 1,500 kcal (men) without medical advice.
Frequently asked questions
Why Mifflin-St Jeor and not Harris-Benedict?
Mifflin-St Jeor (1990) was found more accurate than the older Harris-Benedict equations in comparison studies on modern adults, so it is the default used by many dietitians.
What is the difference between BMR and TDEE?
BMR is what your body burns at complete rest. TDEE (total daily energy expenditure) multiplies BMR by an activity factor to include movement, work and exercise. Eating at your TDEE roughly holds weight steady.
How fast should I lose weight?
About 0.25 to 0.5 kg a week is a common, sustainable rate. A 500 kcal daily deficit gives roughly 0.45 kg a week using the 7,700 kcal per kg rule of thumb. Larger deficits should be supervised by a clinician.
Which activity level should I choose if I am unsure?
Pick the lower one. People usually overestimate exercise, and the factors are multipliers, so one level too high adds 150 to 300 kcal to the answer.