Calorie & TDEE Calculator

Your TDEE is your basal metabolic rate, estimated with the Mifflin-St Jeor equation, multiplied by an activity factor of 1.2–1.9 — an estimate of the total calories you burn per day.

How TDEE is calculated

Your basal metabolic rate (BMR) is the energy your body uses at complete rest to keep your heart, brain, and other organs running. It typically accounts for the largest share of the calories you burn each day. This calculator estimates BMR with the Mifflin-St Jeor equation, which is widely regarded as one of the most accurate formulas for the general adult population.

Here is the equation itself, so you can check the number rather than take it on trust. Weight in kilograms, height in centimetres, age in years:

The only difference between the two is the constant at the end — +5 for men, −161 for women — a gap of 166 kcal at identical height, weight and age.

Worked through: a 30-year-old man of 80 kg and 180 cm gives (10 × 80) + (6.25 × 180) − (5 × 30) + 5 = 800 + 1,125 − 150 + 5 = 1,780 kcal/day. At the moderate activity factor of 1.55 that becomes a TDEE of 2,759 kcal/day. Note the order: BMR is rounded to a whole calorie before the multiplier is applied, so multiplying an unrounded BMR can leave you a calorie adrift.

Multiplying BMR by an activity factor — 1.2 for sedentary up to 1.9 for very active — gives your TDEE, roughly the total calories you burn in a full day. Eat below that number to lose weight, around it to maintain, and above it to gain. Because activity is the part people most often overestimate, choose the level that matches an average week rather than your most active one.

Turning TDEE into a calorie target

A deficit of about 500 calories per day tends to produce around half a kilo (roughly one pound) of fat loss per week, while a similar surplus supports a slow, lean gain. Larger deficits speed things up but are harder to sustain and can cost muscle and energy. Results always vary with sleep, stress, adherence, and individual metabolism, so treat the target as a well-informed starting point.

The most reliable approach is to pick a target, hold it for two to three weeks, and weigh yourself under consistent conditions. If the scale trend isn't moving the way you want, adjust intake by 100–200 calories and reassess. Once you have a calorie goal, our macro calculator splits it into protein, carbs, and fat.

Activity multipliers used

Your TDEE = BMR × the factor for your activity level. BMR uses the Mifflin-St Jeor equation.

One notch on the activity dropdown is worth 17.5% of your BMR

The activity factor is the only input on this form you cannot measure. Age, weight and height are facts you can check. The multiplier is a guess about a typical week. It is also the input with the most leverage over the answer. Hold the man worked through above completely fixed — 30 years old, 80 kg, 180 cm, BMR 1,780 — and change nothing but the dropdown:

One body, one BMR, five answers. The ladder spans 1,246 kcal from bottom to top, and the rungs are evenly spaced because the multipliers are.

Now set that against the goal ladder this calculator prints beneath your result. Mild weight loss subtracts 250 kcal. Weight loss subtracts 500. Lean gain adds 250. A single rung of the activity dropdown is about 311 kcal — larger than the entire mild-loss step, and 62% of the 500 kcal deficit. The input you guessed at outweighs the deficit you chose deliberately.

Worked through: our man belongs at Light, but selects Moderate on the strength of one unusually active week. The tool reads 2,759 and offers 2,259 as his weight-loss target. Measured against his real maintenance of 2,448, that is a deficit of 189 kcal — 38% of the 500 he believed he had picked. He has not miscounted a meal or misweighed a portion. He chose the wrong line in a dropdown, and the arithmetic did the rest.

How these multipliers compare with FAO's

There is an independent way to sanity-check the ladder. FAO/WHO/UNU defines physical activity level as total energy expenditure divided by BMR — PAL = TEE/BMR, which is exactly the operation this calculator performs — and it publishes bands rather than single numbers. Its Table 5.3, “Classification of lifestyles in relation to the intensity of habitual physical activity, or PAL”, lists sedentary or light activity at 1.40–1.69, active or moderately active at 1.70–1.99, and vigorous or vigorously active at 2.00–2.40. Nothing in that table sits below 1.40. The report states that the PAL values which can be sustained for a long period by free-living adult populations range from about 1.40 to 2.40, and it reserves a mean PAL of 1.21 for short-term survival of totally inactive dependent people in conditions of crisis.

So the 1.2 rung that this calculator, along with most others, labels “little or no exercise, desk job” sits below the floor FAO assigns to any free-living lifestyle, and nearer to its crisis figure. Read that as a comparison of multipliers and nothing more: FAO pairs its PAL bands with Schofield-predicted BMR rather than Mifflin-St Jeor, so we are not claiming FAO endorses the calorie figures on this page. The width is the instructive part. Applying FAO's band edges to this man's Mifflin BMR of 1,780, its sedentary-or-light category alone covers 2,492 to 3,008 kcal/day — a spread of 516 kcal inside one category, larger than a full step of our own ladder.

The honest reading is that your TDEE is a band, not a point. For this man, FAO's sedentary-or-light category alone spans 516 kcal. FAO publishes ranges rather than single values. The number on this page is one point inside a range the formula cannot narrow for you. Only the scale can, which is why the advice above is to hold a target for two to three weeks and let the weight trend, rather than the estimate, decide the next adjustment.

BMR uses Mifflin-St Jeor (1990). Activity multipliers follow standard exercise-physiology references; the cross-check above compares them with the PAL lifestyle bands in FAO/WHO/UNU, Human Energy Requirements, Table 5.3. See also NIH and CDC guidance on healthy weight and energy balance.