Calorie Deficit Calculator

How it works

daily deficit = (lb per week × 3,500) ÷ 7 · intake = TDEE − deficit (never below 1,200 kcal for women or 1,500 for men) · weeks = weight to lose ÷ weekly loss · pace by deadline = weight to lose ÷ weeks

The planner uses the classic approximation that one pound of body fat stores about 3,500 kcal (7,700 kcal per kilogram). Choose a weekly pace, or a deadline and let it work out the pace, and it spreads the matching deficit over seven days, subtracts it from your maintenance calories (TDEE) and gives the goal date. Enter your TDEE if you know it, or let the calculator estimate it with the Mifflin-St Jeor equation and your activity level. The daily target is never set below 1,200 kcal for women or 1,500 kcal for men, the usual minimums without medical supervision; if your pace would need less, the plan holds at the minimum and shows the slower pace and later date that follow. In the estimate mode it also re-calculates maintenance every week as your weight falls, so the weekly plan lowers intake to stay on pace, and it shows what happens if you keep eating the starting target instead — loss slows and can level off before the goal, the effect the NIH Body Weight Planner models in detail.

Worked example

With a 2,600-kcal TDEE, losing 1 lb a week needs a 500-kcal daily deficit (1 × 3,500 ÷ 7) — eating about 2,100 kcal a day. Fifteen pounds takes 15 weeks, about 3.5 months. A 35-year-old woman, 5′5″ and 180 lb with light activity, has an estimated TDEE of about 2,079 kcal; at 2 lb a week she would need 1,079 kcal, so the plan holds her at 1,200 kcal — an 879-kcal deficit, about 1.76 lb a week — and reaches a 15-lb goal in about 9 weeks.

Sources: NIDDK — Body Weight Planner and weight management · Mifflin MD et al. (1990) — A new predictive equation for resting energy expenditure · Hall KD et al. (2011) — Quantification of the effect of energy imbalance on bodyweight

Frequently asked questions