Activity scale is the standard clinical-dietetics multiplier set
The activity multipliers this calculator uses
TDEE starts from BMR (Mifflin-St Jeor, 1990) and scales it by a fixed multiplier for how active a typical week looks. These five bands are the standard set used across clinical dietetics and sports nutrition practice for turning a resting number into a livable daily figure.
| Band | Multiplier | Rough description |
|---|---|---|
| Sedentary | 1.2 | Desk job, little deliberate exercise |
| Light | 1.375 | Exercise one to three days a week |
| Moderate | 1.55 | Exercise three to five days a week |
| Active | 1.725 | Hard exercise six to seven days a week |
| Very active | 1.9 | Physical job plus regular training |
Turning one number into three targets
The cut, mild-gain and aggressive-loss rows subtract or add a fixed daily amount from maintenance. The 500-calorie step traces back to a rough rule of thumb from Max Wishnofsky's 1958 paper in the American Journal of Clinical Nutrition, which estimated about 3,500 stored calories per pound of fat. Modern research on metabolic adaptation has shown that rule is an approximation rather than a fixed constant, since the body's own energy needs shift as weight changes, but it still works reasonably well as a planning starting point over a few weeks at a time.
The aggressive-loss row is capped so it never drops below your own BMR, since going lower than that on paper doesn't reflect how the body actually behaves.
Where this differs from BMR alone
BMR by itself only tells you the resting piece. TDEE is the number people actually plan meals and workouts around, because it accounts for the calories your daily movement adds on top. If you want to see the resting number in isolation, or want to double-check the math behind this page, the BMR calculator runs the same underlying equation without the activity step. And if you want to isolate a single gym session rather than the activity multiplier used here, a MET-based tool like the calories burned calculator breaks out that one workout on its own.
FAQs
Why does TDEE change if my activity level hasn't changed?
Because the multiplier only scales BMR, and BMR itself moves with weight and age. Lose 10 pounds and both numbers drop even if your workout schedule stays identical.
Is the aggressive loss option safe for everyone?
Not necessarily. A 1,000-calorie daily deficit is capped at your BMR here, but that floor still isn't automatically appropriate for every body size or health situation. Anyone considering a large deficit should check with a doctor or registered dietitian first.
What if my actual weight trend doesn't match this prediction?
Treat the number as a starting point, not a guarantee. Track your weight for two to three weeks, compare the real trend to the target, and adjust the calorie number up or down based on what actually happened.
Does this double-count exercise if I also log workouts in a fitness app?
It can. The activity-level dropdown already folds regular exercise into the multiplier, so adding a separate calorie credit for the same workouts in another app usually overstates your real total burn.