TDEE Calculator for Weight Loss

How a TDEE-based weight-loss target works

Your TDEE — total daily energy expenditure — is how many calories you burn in a day. Eat less than that, and your body has to make up the difference from stored fat. Eat more, and you store the excess. That's the whole game.

This calculator uses the Mifflin-St Jeor equation to estimate your basal metabolic rate (BMR) — what your body burns at rest — then multiplies it by your activity level to get TDEE. That number is your maintenance. The fat-loss buttons subtract a percentage of it to give you a daily calorie target that drives a specific rate of loss.

Why a percentage deficit beats a fixed number

The old advice was "eat 500 calories below maintenance." That works for a 200-lb person with a TDEE of 2,500. For a 130-lb woman with a TDEE of 1,650, the same 500-cal cut leaves her at 1,150 — too aggressive, too quickly fatigued, and likely to lose muscle alongside fat.

A percentage of TDEE scales with you. 20% of TDEE is a moderate cut whether you're 130 lb or 230 lb. As you lose weight and your TDEE drops, recalculate and the target moves with you.

Slow vs. moderate vs. aggressive — when each makes sense

Slow (~10% deficit): Best if you have less than 15 lb to lose, you're already lean, or you're training hard and don't want performance to drop. ~0.5 lb/week.
Moderate (~20% deficit): The default for most people. ~1 lb/week. Sustainable for 12–16 weeks before you need a maintenance phase.
Aggressive (~25% deficit): Use for short, focused cuts with significant weight to lose. Harder to keep protein high enough, and you'll feel it in the gym. 8 weeks max before you reset to maintenance.

The calorie target is only half the job

Hitting your calorie number with low protein is how people end up "skinny fat" — they lose weight but most of it is muscle. Once you have your daily target from this page, send it to the macro calculator to split it into protein, fat, and carbs. The protein floor matters most — aim for around 1 g per pound of goal body weight.

Then think about food quality. The PE diet framework — high protein per calorie — is the simplest mental model for what to put on the plate inside that calorie budget.

What to expect week-to-week

Fat loss is not linear. Water weight, sodium, the menstrual cycle, stress, and digestive timing all move the scale day-to-day. Weigh yourself daily, average over 7 days, and judge progress on the trend — not the morning's number. If the trend hasn't moved in three weeks, drop calories by ~100/day or add a session of cardio.

Frequently asked questions

How big should my deficit be to lose weight?

A 10–25% deficit below your TDEE is the working range. Below 10% is too slow to notice; above 25% sacrifices muscle and training quality. Most people sit at ~20% (around 500 cal/day below maintenance) and lose about 1 lb per week.

Why does my TDEE matter more than a generic 1,500 cal target?

Generic targets assume an average body, an average activity level, and an average goal. Your TDEE is calibrated to your weight, height, age, gender, and how much you actually move. A 5'2" sedentary woman and a 6'1" active man can't share a calorie number.

Will my TDEE drop as I lose weight?

Yes. A smaller body burns fewer calories. Recalculate every ~10 lb lost and adjust the deficit. The drop is usually 30–60 cal per 10 lb on BMR alone, plus a smaller hit to daily activity costs.

Should I do cardio or just diet down?

Diet drives the deficit. Cardio raises the ceiling and helps protect muscle when combined with resistance training, but you can't out-train a calorie surplus. Get the deficit from food first.

Related tools

Generic TDEE Calculator — the parent page with the full Mifflin-St Jeor explanation.
Macro Calculator — split your target into protein, fat, and carbs.
PE Diet Calculator — audit a food's protein-to-energy ratio.