Health · Nutrition

TDEE Calculator

Estimate your Total Daily Energy Expenditure and maintenance calories using the Mifflin-St Jeor formula. Choose imperial or metric units — free and no sign-up.

How the TDEE calculator works

Your Total Daily Energy Expenditure (TDEE) is the number of calories your body burns in a full day. This calculator builds it up in two steps:

• Step 1 — BMR. Your Basal Metabolic Rate is the energy you burn at complete rest, estimated with the Mifflin-St Jeor equation.
• Step 2 — Activity factor. Your BMR is multiplied by an activity multiplier (1.2 to 1.9) that reflects how active you are.

The Mifflin-St Jeor formula

Weight is in kilograms (kg) and height in centimeters (cm). Imperial inputs are converted automatically (1 lb = 0.453592 kg, 1 in = 2.54 cm):

• Men: BMR = 10 × kg + 6.25 × cm − 5 × age + 5
• Women: BMR = 10 × kg + 6.25 × cm − 5 × age − 161
• TDEE = BMR × activity factor

Activity multipliers

Things to keep in mind

Calorie targets for fat loss and muscle gain

To lose weight, eat below your TDEE — about 500 calories per day below maintenance targets roughly one pound of fat loss per week. To gain weight or build muscle, eat in a moderate surplus, such as 300 calories above maintenance. These figures are starting points, not guarantees.

Activity level is the biggest source of error

People often overestimate how active they are, which inflates their TDEE. If you sit most of the day and train a few times a week, "moderately active" is usually closer to the truth than "very active." Track your weight for two to four weeks and adjust your intake based on what actually happens.

Frequently asked questions

Understanding your basal metabolic rate (BMR)

Before you can understand your TDEE, it helps to understand the number that sits underneath it: your Basal Metabolic Rate, or BMR. Your BMR is the amount of energy your body would burn in a full 24-hour period if you did nothing at all — no walking, no eating, no exercise — just lying still in a warm room. That sounds like a small number, but it is actually the largest single component of your daily calorie burn. For most adults, BMR accounts for roughly 60 to 70 percent of total daily energy expenditure. Your heart pumping blood, your lungs moving air, your kidneys filtering, your brain running, and the constant turnover of cells all cost energy, and that energy never stops being spent.

Several things influence how high your BMR is. Body size matters most: a larger body has more tissue to maintain, so taller and heavier people generally have higher BMRs. Lean muscle mass is metabolically active and burns more energy at rest than fat tissue, which is one reason strength training can gently raise your resting burn over time. Age plays a role too — BMR tends to decline slowly through adulthood, partly because we tend to lose muscle as we get older. Sex is also a factor: because men on average carry more lean mass, the Mifflin-St Jeor formula adds 5 for men and subtracts 161 for women to reflect that difference.

The Mifflin-St Jeor equation explained

This calculator uses the Mifflin-St Jeor equation, first published in 1990, to estimate your BMR. It has become the default choice for most dietitians and fitness professionals because studies comparing predictive equations against measured metabolism have repeatedly found it to be one of the most accurate for the general population. It tends to outperform the older Harris-Benedict equation, especially for people who are overweight.

The equation itself is straightforward. Weight is in kilograms and height is in centimeters, so if you enter imperial units this tool converts them automatically using 1 pound = 0.453592 kilograms and 1 inch = 2.54 centimeters. For men, BMR equals 10 times your weight in kg, plus 6.25 times your height in cm, minus 5 times your age, plus 5. For women, the formula is identical except it ends by subtracting 161 instead of adding 5.

It is worth understanding what the equation can and cannot do. Because it only uses age, sex, height and weight, it does not know how much of your body weight is muscle versus fat. A very muscular person and a less lean person of the same height, weight, age and sex will get the same BMR estimate, even though their true resting metabolisms may differ. That is the trade-off of any simple formula: it is fast, free and accurate enough for the vast majority of people, but it is still an estimate.

From BMR to TDEE: the activity multiplier

Your BMR only describes complete rest. To turn it into a realistic daily target, you multiply it by an activity factor that reflects how much you move. The table below shows a sample for a person with a BMR of about 1,700 kcal, so you can see how dramatically your daily lifestyle changes the final number.

Notice that the gap between sedentary and extra active is nearly 1,200 calories per day — almost as much as some people eat in an entire meal. This is why choosing your activity level honestly is the single most important thing you can do for an accurate result. The multiplier is meant to capture everything outside of formal exercise too, including walking, standing, fidgeting and your job, which sports scientists group together under the term NEAT (non-exercise activity thermogenesis).

Using your TDEE to lose, gain or maintain weight

Once you know your TDEE, the principle of weight change becomes simple, even if the practice takes patience. Your TDEE is your maintenance level — eat that many calories and your weight should stay roughly stable over time. To lose weight you create a deficit by eating below it; to gain weight you create a surplus by eating above it.

A widely used guideline is that a deficit of about 500 calories per day targets roughly one pound of fat loss per week, because a pound of body fat stores approximately 3,500 calories of energy. For gaining, a smaller surplus of around 250 to 500 calories per day supports a slower, leaner gain with less unwanted fat. The table below shows typical targets built from a 2,600 kcal TDEE.

Metabolic adaptation: why progress can stall

If you have ever dieted for several weeks and watched the scale slow down or stop, you have likely experienced metabolic adaptation. As you lose weight, your TDEE naturally falls for two reasons. First, a lighter body needs less energy to move and maintain, so your BMR drops. Second, prolonged dieting can quietly reduce your non-exercise movement — you take fewer steps, fidget less and feel less energetic — which lowers the activity portion of your burn. The result is that the deficit you started with shrinks over time.

This is normal and not a sign that your metabolism is broken. The practical response is to recalculate your TDEE every few weeks using your new, lower body weight, and to base your next target on real-world results rather than the original number. Tracking your weight as a weekly average, rather than reacting to daily fluctuations from water and food, gives you a far clearer signal of whether your current intake is actually producing the change you want.

Common misconceptions about TDEE

"My metabolism is so slow that calories don't apply to me." True clinical differences in metabolism between similar people are usually modest — on the order of a couple hundred calories, not a thousand. Far more often, the gap between expected and actual results comes from underestimating intake and overestimating activity, both of which are extremely common.

"Eating more often boosts my metabolism." Meal frequency has little meaningful effect on total daily energy expenditure. Whether you eat three meals or six, your total intake is what determines weight change. Choose the meal pattern that helps you stay consistent.

"The calculator number is exact, so I must eat precisely that amount." Every TDEE figure, from any calculator, is an educated estimate. Treat it as a starting hypothesis, then let two to four weeks of real data confirm or adjust it.

Smart ways to use this calculator

• Start conservative on activity. When in doubt, pick the lower activity level. It is easier to add food when progress is too fast than to keep cutting from an inflated number.
• Re-run it monthly. Your TDEE changes as your weight changes, so update the inputs roughly once a month rather than relying on a single old result.
• Pair it with the macro split. Once you have your calorie target, feed it into the macro calculator to turn the number into daily protein, carbs and fat in grams.
• Judge it by the scale, not the formula. If your weight is not moving the way the target predicts after a few weeks, adjust your intake by 100 to 200 calories and observe again.