TDEE Calculator
Calculate your Total Daily Energy Expenditure using the Mifflin-St Jeor equation. Enter your age, gender, measurements, and activity level to find your maintenance calories, BMR, and calorie targets for weight loss or gain.
What Is TDEE and Why Does It Matter?
TDEE stands for Total Daily Energy Expenditure. It represents the total number of calories your body uses in a 24-hour period, accounting for everything from involuntary processes like your heartbeat and digestion to voluntary activities like walking, exercising, and fidgeting.
Your TDEE breaks down into several components. The largest is your Basal Metabolic Rate, which typically accounts for 60 to 75 percent of total expenditure. BMR covers the energy cost of keeping you alive while doing absolutely nothing — lying still, breathing, maintaining body temperature, running organ systems. The second component is the thermic effect of food (TEF), which represents the energy used to digest, absorb, and process nutrients. TEF accounts for roughly 10 percent of total calories consumed. The third component is physical activity, both structured exercise and non-exercise activity thermogenesis (NEAT), which together make up the remaining 15 to 30 percent.
Knowing your TDEE gives you a concrete number to work with. If your goal is to maintain your current weight, you eat at or near your TDEE. To lose weight, you create a calorie deficit by eating below TDEE. To gain weight, you eat above it. The size of the deficit or surplus determines the pace of change. A 500-calorie daily deficit translates to roughly one pound of fat loss per week, since a pound of body fat stores approximately 3,500 calories. These numbers are estimates, and individual metabolism varies, but they provide a reliable starting framework that you can adjust based on real-world results over time.
Understanding the Activity Level Multipliers
The activity factor multiplied against your BMR is arguably the most impactful — and most frequently misjudged — variable in the TDEE equation. Most people overestimate their activity level. Being honest with yourself here makes the difference between a useful calorie target and a misleading one.
Sedentary (factor 1.2) describes someone who works a desk job, drives to work, and does not engage in regular exercise. Walking from the parking lot to the office and doing household chores does not move you out of this category. A large percentage of adults in developed countries fall here, even if they don't think of themselves as sedentary.
Lightly active (1.375) fits someone who exercises one to three days per week at a moderate intensity, or who has a job that involves some walking and standing. A teacher who is on their feet most of the day but doesn't exercise regularly might belong here. So would an office worker who jogs twice a week for 30 minutes.
Moderately active (1.55) applies to consistent exercisers who train three to five days per week with meaningful intensity — running, cycling, weight training, group fitness classes. This level assumes the exercise sessions are at least 30 to 60 minutes and genuinely challenging, not leisurely strolls.
Active (1.725) is for people who train hard six or seven days a week. Competitive athletes during their training season, construction workers who also hit the gym, or individuals who combine demanding physical jobs with regular workouts typically fall here.
Very active (1.9) is reserved for people with extreme physical demands: professional athletes during peak training blocks, military personnel in active training, or anyone combining a physically grueling job with intense daily exercise. Very few people truly belong in this category.
Using TDEE for Weight Management Goals
Once you have your TDEE number, the arithmetic of weight management is straightforward, even if the execution takes discipline. Your body obeys the laws of thermodynamics. Over any sustained period, if you consume more calories than you expend, you will gain weight. Consume fewer, and you will lose it. The TDEE gives you the break-even point.
For fat loss, a daily deficit of 250 calories (mild loss) produces roughly half a pound of loss per week. A 500-calorie deficit targets about one pound per week. These are moderate, sustainable rates that minimize muscle loss and metabolic adaptation. Deficits larger than 1,000 calories per day are generally discouraged by dietitians because they increase the risk of nutrient deficiencies, hormonal disruption, and muscle catabolism.
For muscle gain, a modest surplus of 200 to 300 calories per day supports lean mass growth when combined with progressive resistance training. Larger surpluses accelerate weight gain but proportionally more of it tends to be fat rather than muscle. The body can only synthesize a limited amount of muscle tissue per day regardless of how many extra calories you provide.
Protein intake matters regardless of your goal. Research consistently supports 0.7 to 1.0 grams of protein per pound of body weight for individuals engaged in regular training. Adequate protein preserves lean mass during a deficit and provides the building blocks for growth during a surplus.
Track your weight over two to four weeks and compare the trend to your calorie intake. If you aren't losing weight at a 500-calorie deficit, your actual TDEE is likely lower than the estimate, and you should adjust down by 100 to 200 calories. If you're losing faster than expected, bump calories up slightly. The formula gives you a starting point; your bathroom scale gives you the feedback to fine-tune it.
TDEE vs BMR: Why the Distinction Matters
People sometimes confuse TDEE and BMR, or treat them as interchangeable. They're related but quite different numbers, and mixing them up can lead to eating way too little or way too much.
BMR, your Basal Metabolic Rate, is the calorie cost of simply existing. Imagine lying perfectly still in bed all day without eating, talking, or even getting up to use the bathroom. The energy your body burns just to keep your heart beating, your lungs inflating, your cells dividing, and your brain running background processes — that's your BMR. For most adults, BMR falls somewhere between 1,200 and 2,000 calories per day, depending on body size, muscle mass, age, and sex.
TDEE adds everything else on top of that foundation. It includes the thermic effect of food, which is the energy your body spends breaking down and absorbing nutrients. It also includes all forms of physical activity: your morning run, your walk to the store, fidgeting in your chair, even standing up from the couch. For an active person, TDEE can be 50 to 90 percent higher than BMR.
Why does this distinction matter practically? Because eating at your BMR level is not the same as creating a moderate calorie deficit. If your TDEE is 2,500 calories and your BMR is 1,600, eating 2,000 calories per day gives you a comfortable 500-calorie deficit. But eating 1,600 calories would create a 900-calorie deficit — aggressive enough to trigger metabolic slowdown, muscle loss, and the kind of persistent hunger that makes most diets fail within weeks.
A good rule of thumb is to never eat below your BMR unless you're under direct supervision from a healthcare provider. Your BMR represents your body's minimum operating budget. Dipping below it for extended periods is like running a company without paying the electricity bill — things start breaking down. The sweet spot for sustainable fat loss sits between your BMR and your TDEE, typically 300 to 500 calories below your maintenance level.
Mifflin-St Jeor Equation
BMR = (10 x weight_kg) + (6.25 x height_cm) - (5 x age) + s
The Mifflin-St Jeor equation estimates Basal Metabolic Rate, the number of calories your body burns at complete rest to maintain basic functions like breathing, circulation, and cell production. The variable s equals +5 for males and -161 for females. Weight is entered in pounds and converted to kilograms (divide by 2.20462). Height is entered in inches and converted to centimeters (multiply by 2.54). TDEE is then calculated by multiplying BMR by an activity factor ranging from 1.2 for sedentary individuals to 1.9 for very active individuals.
Where:
- weight_kg = Body weight in kilograms (lbs divided by 2.20462)
- height_cm = Height in centimeters (inches multiplied by 2.54)
- age = Age in years
- s = Sex constant: +5 for males, -161 for females
Example Calculations
30-Year-Old Active Male
Calculating TDEE for a moderately active man of average build.
Weight in kg: 170 / 2.20462 = 77.1 kg. Height in cm: 70 x 2.54 = 177.8 cm. BMR = (10 x 77.1) + (6.25 x 177.8) - (5 x 30) + 5 = 771 + 1111.25 - 150 + 5 = 1,737 calories. Multiplied by the moderate activity factor of 1.55 gives TDEE = 1,787 x 1.55 = 2,770 calories. Exercise calories: 2,770 - 1,787 = 983 calories from activity.
25-Year-Old Sedentary Female
Calculating TDEE for a young woman with a desk job and minimal exercise.
Weight in kg: 140 / 2.20462 = 63.5 kg. Height in cm: 65 x 2.54 = 165.1 cm. BMR = (10 x 63.5) + (6.25 x 165.1) - (5 x 25) - 161 = 635 + 1031.9 - 125 - 161 = 1,381 calories. With a sedentary factor of 1.2: TDEE = 1,452 x 1.2 = 1,742 calories. Exercise calories: 1,742 - 1,452 = 290 calories from daily activity.
Frequently Asked Questions
BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest, performing only involuntary functions like breathing and circulation. Think of it as your energy cost for simply existing. TDEE (Total Daily Energy Expenditure) takes your BMR and multiplies it by an activity factor to account for all the additional energy you burn through movement, exercise, digestion, and daily activities. BMR is always lower than TDEE because it does not include any physical activity.
The Mifflin-St Jeor equation, published in 1990, has been validated in multiple studies as the most accurate predictive equation for estimating BMR in the general population. A 2005 review by the American Dietetic Association compared it against the Harris-Benedict equation (1919), the Owen equation (1986), and the WHO/FAO equations, and found that Mifflin-St Jeor predicted measured resting metabolic rate within 10 percent for the largest percentage of individuals tested. It is now the equation recommended by most clinical nutrition guidelines.
The Mifflin-St Jeor equation predicts BMR within about 10 percent of measured values for most healthy adults. The activity multiplier introduces additional uncertainty because it relies on subjective self-assessment. Overall, expect your true TDEE to fall within roughly 10 to 15 percent of the calculated value. Use the estimate as a starting point, then adjust based on actual weight change over two to four weeks. If your weight is stable, your intake matches your real TDEE.
Eating below your BMR is generally not recommended except under medical supervision. Your BMR represents the minimum energy your body needs for basic physiological functions. Chronic under-eating below BMR can lead to muscle loss, nutrient deficiencies, hormonal imbalances, metabolic slowdown, and impaired immune function. A safer approach is to create a moderate deficit of 250 to 500 calories below your TDEE while keeping intake above your BMR. This supports steady fat loss while maintaining energy and health.
The Mifflin-St Jeor equation subtracts 5 calories per year of age, reflecting the well-documented decline in metabolic rate as people get older. This decline is primarily driven by loss of lean muscle mass, which is more metabolically active than fat tissue. A 50-year-old and a 25-year-old who are otherwise identical in weight, height, gender, and activity level will differ by 125 calories in BMR. Resistance training can partially offset age-related muscle loss and its metabolic consequences.
For weight loss, subtract 300 to 500 calories from your TDEE. This creates a moderate deficit that promotes roughly half a pound to one pound of fat loss per week without excessive hunger or muscle wasting. For muscle gain, add 200 to 300 calories above your TDEE while following a progressive resistance training program. Protein should be kept at around 0.8 to 1.0 grams per pound of body weight in either scenario. Monitor your weight and body composition over several weeks and adjust your intake by 100 to 200 calories if progress stalls or moves too fast.