Daily deficit (Wishnofsky 1958):

daily_deficit = (lb_per_wk × 3500) / 7

Source: Wishnofsky M. Caloric equivalents of gained or lost weight. Am J Clin Nutr 6(5):542-546, 1958. PubMed: 13594881

Target intake (with floor):

target = max(TDEE − daily_deficit, floor) where floor = 1500 kcal (men) / 1200 kcal (women), per Mayo Clinic and Academy of Nutrition and Dietetics guidance.

Timeline projection:

weeks_to_goal = (current_weight − goal_weight) / lb_per_wk

Caveat — Hall et al. 2008/2013:

The linear Wishnofsky rule overestimates real long-term loss by roughly 30% as metabolism adapts (Hall et al., Lancet 2008; Int J Obesity 2013). For a dynamic-model alternative, see the NIDDK Body Weight Planner .

TDEE (compute mode): BMR via Mifflin-St Jeor (1990) or Katch-McArdle (when body-fat % is provided), multiplied by the activity factor. See the TDEE Calculator for details.