No multiplier TDEE

Basis. The Katch–McArdle equation predicts resting expenditure from fat-free mass. The linked clinical analysis states this exact equation.

Nuance. It is more accurately a resting metabolic rate prediction, although calculators commonly label it BMR. A prediction is not indirect calorimetry. Body-fat error changes lean mass and therefore the result; illness, energy restriction, age, and individual physiology can also make measured RMR differ.

Basis. Height correlates with step length, and the default lands near preferred step lengths in published gait datasets.

Nuance. The coefficient itself is a convenience heuristic, not a universal physiological constant. Speed, leg length, age, terrain, and gait all matter. That is why measured step length can override it.

Basis. The ACSM level-walking equation assigns 0.1 mL O₂/kg per metre to horizontal movement. Across 1 km, using about 5 kcal per litre O₂, that converts to roughly 0.5 kcal/kg/km above rest.

Nuance. This is net cost because BMR is already included. A clinical statement reports gross walking cost around 1.15 kcal/kg/mile (about 0.71/kg/km). Grade, load, surface, gait, and unusual speeds change cost.

Basis. NEAT genuinely includes posture, fidgeting, and daily activity outside formal exercise. Research shows very large person-to-person responses.

Choice. The 150 kcal baseline and 0.7/1.0/1.3 optimism settings are not research-derived population averages. They are a deliberately visible estimate for movement missed when people do not carry their phones. Occupation and habits can make them badly wrong; calibrate against multi-week trends.

Basis. This is not an equation used by the calculator; it is an opt-in user input that replaces the step-derived movement subtotal.

Nuance. Consumer-device energy estimates vary substantially, and resistance training is a particularly poor use case. In this mode the number is treated as a rough fallback only. It must not include lifting or exercise entered elsewhere, otherwise the total is double-counted. Background NEAT is still added for activity missed without the phone.

Basis. Studies using indirect calorimetry report very different costs across protocols. One study measured roughly 124–132 kcal during a session and another 20–25 kcal during the following hour.

Choice. Intensity bases, volume factors, linear body-weight scaling, 5–15% EPOC, and the 250 kcal cap are conservative product decisions—not a validated resistance-training equation. Reviews disagree on which training variables best predict expenditure.

Wearables. They are not assumed to always overestimate: validation studies find both over- and underestimation. The useful conclusion is that resistance-training calorie estimates are unreliable, with reported mean absolute errors ranging roughly 15–57%.

Basis. These are midpoints within commonly reported ranges: protein about 20–30%, carbohydrate 5–10%, and fat 0–3%.

Choice. By default, the model assigns 55% of non-protein calories to carbohydrate and 45% to fat. Enabling manual macros replaces that split with entered carbohydrate and fat grams. Any unassigned calories are treated conservatively as fat; entering complete macros improves this component.