TDEE calculator

Using the targets without sabotaging them

The single most common way people break this calculation is double-counting exercise. The activity multiplier already contains your training: if you selected "moderate" because you lift four days a week, those workouts are baked into the maintenance number, and eating back exercise calories on top of it erases the deficit you thought you had. Pick the tier that describes your week, then treat workout days and rest days as the same calorie target. If a fitness tracker tells you that you "earned" 400 more calories, this page and the tracker are answering the same question twice; use one, not both.

Also know that your TDEE is a moving target. Lose ten pounds and the body being fed is smaller, so maintenance drops and yesterday's deficit shrinks. The practical rhythm: recalculate roughly every ten pounds of change, and expect progress to slow even when compliance is perfect. That slowdown is arithmetic, not failure.

Look at where the cut target lands relative to the BMR stat. When the two are close, as they often are for smaller or lighter people, a flat 500-calorie deficit is aggressive, and a smaller deficit with more patience holds up better. The 500 figure is a convention, not a floor you owe anyone.

A worked calculation

A 42-year-old woman, 165 cm and 68 kg, with light activity (exercise one to three days a week). Her BMR by Mifflin-St Jeor is 10 x 68 + 6.25 x 165 - 5 x 42 - 161 = 1,340 calories at rest. Multiplied by the 1.375 light-activity factor, maintenance comes out to 1,843 calories. The cut target shows 1,343 and the gain target 2,143. Notice her cut number sits almost exactly at her BMR, the situation described above where a gentler deficit is the smarter opening move. For comparison, the page's default 30-year-old male at 5'10" and 175 pounds with moderate activity works out to a BMR of 1,760 and a TDEE of 2,728.

What happens between input and output

Imperial entries convert to centimeters and kilograms first, then feed the Mifflin-St Jeor equation, with the +5 or -161 constant selected by sex. The result is BMR, the energy cost of simply existing at rest, which is multiplied by your chosen activity factor, from 1.2 for sedentary up to 1.9 for athletes with physical jobs. The cut and gain stats are plain offsets from maintenance, minus 500 and plus 300, sized for roughly a pound lost per week and a lean pace of gaining. Everything rounds to whole calories, and age is bounded to 15 through 100 because the equation was not built for children.

Reasons your real number will differ

Any BMR equation predicts a population average from four inputs, and individuals scatter around it, commonly by a couple hundred calories in either direction. Muscle mass is the biggest invisible factor: two people with identical stats but different builds burn differently, and the equation cannot see composition. Adaptive changes during a long diet, thyroid conditions, and medications all shift energy needs in ways no formula captures. The number here is the right starting hypothesis, and your scale trend over two to three weeks is the experiment that corrects it. For medical weight questions, a clinician or dietitian beats any calculator, this one included.