TDEE Calculator: Estimate Your Daily Energy Expenditure

How this TDEE estimate works

Total daily energy expenditure (TDEE) is the energy you use across an entire day. This calculator first estimates resting energy expenditure with the Mifflin-St Jeor equation: for men, 10 × weight in kilograms + 6.25 × height in centimeters − 5 × age + 5; for women, the final constant is−161. It then multiplies that result by the selected activity factor. The original resting equation comes from Mifflin MD et al., American Journal of Clinical Nutrition (1990) (Resting energy expenditure equation; PMID 2305711.). The broader energy-budget method—total expenditure as basal expenditure multiplied by a physical activity level—is described by FAO/WHO/UNU Human Energy Requirements (2004) (TEE as basal energy expenditure multiplied by physical activity level.).

A worked TDEE example

Consider a 30-year-old man who weighs 180 lb (81.65 kg), is 70 inches tall (177.8 cm), and selects “moderately active.” His estimated resting expenditure is 10 × 81.65 + 6.25 × 177.8 − 5 × 30 + 5 = about 1,783 kcal/day. Applying the 1.55 activity factor gives 1,783 × 1.55 = approximately2,764 kcal/day. That number is not a promise that exactly 2,764 calories will maintain his weight. It is a testable starting hypothesis. If his carefully tracked average intake is near that value but his multi-week weight trend falls, his real maintenance expenditure is probably higher; if it rises, it is probably lower.

Where the activity multipliers come from—and where they do not

The familiar 1.2, 1.375, 1.55, 1.725, and 1.9 ladder is a classic fitness-calculator convention. It is often presented as though each value were validated specifically for “one to three” or “three to five” workouts, but that exact labeled ladder does not come from the Mifflin paper. Its provenance is less direct than the resting equation, and the categories compress jobs, walking, exercise, and spontaneous movement into one choice. FAO/WHO/UNU supports the general physical-activity-level concept, not perfect precision for these popular labels. Two people doing the same gym sessions can have different expenditure because one sits all day and the other has an active job.

Common mistakes

• Counting only workouts. Activity level should represent the whole week, including work, commuting, steps, chores, and recovery days.
• Treating the output as measured metabolism. An equation based on population averages cannot observe your lean mass, movement efficiency, or adaptive responses.
• Reacting to a few scale readings. Water, glycogen, sodium, and digestion can hide the underlying trend; use consistent conditions and several weeks.
• Double-counting exercise calories. If activity is already represented in the multiplier, adding every watch-reported workout calorie can inflate the target.

Limitations and responsible use

Input accuracy matters, wearable calorie estimates are uncertain, and a single activity category cannot capture day-to-day variation. The binary sex input reflects how the published equation is parameterized; it is not an assessment of gender identity and may be a poor fit for some people. Growth, pregnancy, lactation, illness, medication, disability, high-level sport, and a history of disordered eating require individualized guidance. This result is an estimate for general planning, not a diagnosis or medical advice. A registered dietitian or clinician can help when changing intake could create health risk.

Sources

• Mifflin MD et al., American Journal of Clinical Nutrition (1990) — Resting energy expenditure equation; PMID 2305711.
• FAO/WHO/UNU Human Energy Requirements (2004) — TEE as basal energy expenditure multiplied by physical activity level.

Frequently asked questions