TDEE Calculator

What TDEE means in plain terms

TDEE stands for total daily energy expenditure, which is the number of calories your body burns in a full day. It is not the number on a food label and it is not the number your watch guesses. It is a budget: eat below it and you lose weight, eat above it and you gain, and eat at it and your weight holds steady over months.

The total is built from four pieces. Your basal metabolic rate, or BMR, is what you burn lying still, and it covers breathing, circulation, cell repair and brain activity. Thermic effect of food is the energy spent digesting, roughly 10 percent of what you eat. Exercise adds whatever your workout costs. Non exercise activity thermogenesis, which everyone calls NEAT, covers everything else you do while awake: walking to the car, folding laundry, standing at a counter, fidgeting.

BMR is the biggest piece, usually 60 to 70 percent of the total for someone with a desk job. That is why a formula built on body size gets you most of the way there, and why the activity multiplier is the part that needs your honest input. Two people with the same BMR can differ by 700 calories a day based on how much they move, and no formula can see that from the outside.

Mifflin-St Jeor: the BMR formula this tool uses

The calculator uses the Mifflin-St Jeor equation, published in 1990 and still the one most dietitians reach for. It beat the older Harris-Benedict equation in validation studies and it needs only four inputs: weight, height, age and sex. The math runs in metric units, so the tool converts pounds to kilograms and feet and inches to centimeters first.

For men the equation is 10 times weight in kilograms, plus 6.25 times height in centimeters, minus 5 times age, plus 5. For women the same terms apply with minus 161 at the end instead of plus 5. The sex constant is not a moral judgment, it reflects average differences in lean mass and body composition across large populations.

Take a 35 year old man who weighs 180 pounds and stands 5 feet 10 inches. His weight is 81.65 kilograms and his height is 177.8 centimeters. That gives 816.5 plus 1,111.3 minus 175 plus 5, which is 1,757.7, and the calculator rounds it to 1,758 calories. A 42 year old woman at 150 pounds and 5 feet 5 inches lands at 1,341 calories, because she is lighter, shorter, older and carries the female constant.

One caution about the formula: it was built on people with typical body composition, and it overestimates for people carrying a lot of excess fat, since fat tissue burns far less than muscle. If your body mass index is above 35, treat the result as a ceiling and expect your real maintenance to run lower.

Activity multipliers: the step that changes the most

The multiplier turns BMR into TDEE. Pick the row that matches a normal week, not your best week. Most people overestimate here by one full level, which is worth 300 to 400 calories a day and explains a lot of stalled diets.

The gap between sedentary and moderately active is 615 calories for the same body. That is the difference between maintaining at 2,724 and gaining a pound every six days at that intake. Be strict with yourself when you pick: three 45 minute gym sessions plus a desk job is lightly active, not active, because the other 160 hours of the week are sitting still.

If you wear a step counter, a rough mapping helps. Under 5,000 steps a day is sedentary. Around 7,500 fits lightly active. Around 10,000 with three workouts fits moderately active. Above 12,500 with daily training fits active. Steps are a proxy, not a measurement, but they are a better proxy than a feeling.

Worked example: a 180 pound man at five levels

Same person, five multipliers. The BMR of 1,758 does not move, so every difference below comes from activity alone. This is the fastest way to see how much the answer depends on the row you pick.

Every 30 pounds of body weight adds about 136 calories to BMR at this height and age, and about 211 calories to TDEE at the moderate level. That is why weight loss slows as you lose: a 240 pound man maintaining on 3,146 who drops to 210 now maintains on 2,935, a drop of 211 calories he has to account for or the loss stalls.

The activity swing is larger than the weight swing. Moving from sedentary to moderate at a constant 180 pounds is worth 615 calories, more than four times the effect of losing 30 pounds. For most people the easier lever is a daily walk, not a stricter diet. A 30 minute walk at a brisk pace burns roughly 150 calories for this body, and it also lifts NEAT for the rest of the day.

Cutting, maintaining and bulking: how big a gap

A pound of body fat stores roughly 3,500 calories, so a daily deficit of 500 calories predicts about a pound of loss a week. That is the origin of the standard advice, and it holds reasonably well over the first month. The sane range for a cut is 250 to 500 calories below TDEE, which is half a pound to one pound a week.

On the gain side the numbers are smaller for a reason. Muscle grows slowly, and a surplus above roughly 300 calories a day mostly adds fat. A beginner can build about 1 to 2 pounds of muscle a month, a trained lifter closer to half a pound. Eating 1,000 calories over maintenance does not double that rate, it just adds fat that has to be cut later.

Two guardrails matter more than the exact number. Keep protein high enough that the loss comes from fat rather than muscle, and keep lifting, because a deficit without resistance training spends muscle along with fat. A 500 calorie deficit with 130 grams of protein and three lifting sessions a week looks nothing like the same deficit with none.

Why the scale stalls after two weeks

Water is the reason. Glycogen stores about 3 grams of water for every gram of carbohydrate, so the first week of a cut drops several pounds of water before any fat moves. Sodium, a hard workout, a poor night of sleep and the menstrual cycle all shift the number by 2 to 4 pounds without touching body fat. A single morning weigh in tells you almost nothing.

Adaptive thermogenesis is the second reason. Eat less for a few weeks and the body responds: NEAT drops, you take fewer steps without noticing, you sit more, you fidget less. Studies put the size of that drop at 100 to 300 calories a day in a moderate deficit, which can erase a 250 calorie gap entirely. That is not a broken metabolism, it is a quieter day.

The fix is measurement rather than willpower. Weigh yourself every morning under the same conditions, then compare weekly averages rather than daily numbers. If the average has not moved in three weeks and you are tracking intake honestly, cut 100 to 150 calories or add 2,000 steps a day. Do one or the other, not both, so you can tell what worked.

A food log is only as good as its portions. Cooking oil, nut butter, cheese, salad dressing and cream in coffee are the five items people under count most, and together they can hide 400 calories a day. Weigh those for two weeks and the stall usually explains itself.

Protein, steps and the parts a formula cannot see

Protein is the input that protects muscle in a deficit and keeps you full. A common target is 1.6 grams per kilogram of body weight, which is 0.73 grams per pound. For the 180 pound man in the example that is 131 grams a day, and it is the same target whether he is cutting or maintaining, because the point is preserving lean mass.

Fiber and food volume do the rest of the satiety work. The Dietary Guidelines for Americans put fiber at 25 to 30 grams a day for most adults, and a diet built on beans, vegetables, fruit and whole grains hits that while staying under a calorie target. Protein and fiber together are why a 2,000 calorie day of real food feels different from 2,000 calories of snacks.

Medical conditions change the math. Thyroid disease, PCOS, insulin resistance, pregnancy and some medications all shift energy use or water balance, and a formula cannot correct for any of them. The NIDDK body weight planner from the National Institutes of Health models weight change over time with a different method, which is a useful cross check on this one. The CDC guidance on losing weight sticks to the 1 to 2 pound per week range for good reason.

This is an estimate for planning, not medical advice. Treat the number as a starting point, adjust from real results over three weeks, and talk to a doctor before a large deficit, especially with a health condition or medication.