Calorie Deficit Calculator

Our calorie deficit calculator translates your height, weight, age, sex, and activity into clear daily targets. Instead of guessing whether you should eat 1,600 or 2,100 calories, you estimate your resting metabolic rate (RMR), multiply by an activity factor for Total Daily Energy Expenditure (TDEE), then pick a daily deficit that fits your timeline and lifestyle. This approach keeps you above a safety floor so you can train, sleep, and feel human while still making steady progress. Because energy balance is governed by averages, the right plan emphasizes consistency over perfection: a sensible calorie target, enough protein, and smart adjustments based on the trend.

From RMR to TDEE: understanding your burn

RMR is the energy you’d burn lying still; TDEE adds what you spend moving, training, and simply living. The calculator uses the widely accepted Mifflin–St Jeor equation to estimate RMR, then multiplies by your chosen physical activity level (PAL). If you’re unsure, pick the lowest activity level that describes most weeks. When in doubt, let your weight trend be the referee: if weight isn’t moving as expected after two to three weeks, nudge calories or activity by a small amount and reassess.

How big should the deficit be?

A common target for sustainable fat loss is about 500 kcal/day, which averages roughly one pound per week in the US system (or ~0.45 kg/week). Smaller deficits like 250 kcal/day preserve training quality, sleep, and mood—excellent for long horizons. Larger deficits can work in the short term but increase fatigue and the temptation to overeat later. The tool shows an approximate safety floor (e.g., around RMR×1.15 and never below 1,200–1,500 kcal for most adults) to help you stay fueled.

Why macros matter

Protein supports muscle retention and satiety; carbs fuel training and recovery; fats support hormones and fat-soluble vitamins. There is no single best split—preferences, digestion, and performance all matter. That’s why your results include quick macro presets (Balanced, Low-Fat, Low-Carb, High-Protein) with gram targets for any calorie level. If lifting or high-intensity training is a priority, you’ll likely feel better with moderate carbs and high protein; if you prefer higher-fat foods and lower carb intake, pick a split that helps you adhere.

Adjusting based on the trend

Scale weight bounces from water, sodium, and glycogen. Track the weekly averageand compare week to week. If the four-week trend is flat, reduce intake by ~100–150 kcal/day or add a small, sustainable amount of activity. If the trend drops too fast and energy or training quality suffer, add back ~100–150 kcal/day. Small changes compounded over months beat dramatic swings that you can’t sustain.

Make it livable

The best plan is one you can repeat on busy days. Eat foods you enjoy, keep protein present at each meal, and aim for fiber and hydration. Plan around social events instead of “starting over” after them. Use the calculator to anchor your daily target, then build a routine—meals you like, grocery lists that fit your budget, and a training plan that matches your recovery. Consistency drives results, and consistency comes from a plan built for real life.