BMR, TDEE and what they mean
Your body burns energy even at rest, keeping your heart beating, lungs working and organs running. That minimum is the basal metabolic rate, or BMR. Total daily energy expenditure, TDEE, adds the calories burned by movement, exercise and digesting food. Eating around your TDEE keeps weight roughly steady, eating less leads to gradual loss, and eating more leads to gain. This calculator estimates both numbers so you have a starting point for planning.
The formula used
The tool uses the Mifflin-St Jeor equation, published in 1990 and widely used by dietitians because it performed better than older equations in validation studies. For men, BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5. For women the final constant is −161 instead of +5. TDEE is BMR times an activity factor: 1.2 for a sedentary lifestyle, 1.375 for light activity, 1.55 for moderate, 1.725 for very active and 1.9 for extra active. A 30-year-old man of 178 cm and 78 kg has a BMR near 1,780 calories and, at moderate activity, a TDEE of about 2,760.
Using the results for weight change
- A deficit of roughly 500 calories per day is commonly associated with losing around half a kilogram, or one pound, per week. Real results vary because the body adapts.
- A small surplus of 250 calories is typical for slow, lean weight gain alongside strength training.
- Avoid very low intakes without medical supervision. Many guidelines advise not dropping below about 1,200 calories a day for women or 1,500 for men.
How accurate is it?
Predictive equations can be off by 10% or more for an individual, because body composition, genetics, medication and daily movement differ. The activity multiplier is the biggest source of error, since people overestimate how active they are. Track your weight and intake for two to four weeks and adjust the target based on what actually happens. This tool is for general information and is not medical advice, and it is not suitable for people under 15, pregnant women or anyone managing a medical condition.
Privacy
All the arithmetic is performed in your browser. Your measurements are not stored or sent anywhere.