The fundamentals

What is TDEE?

TDEE stands for Total Daily Energy Expenditure. It's the total number of calories your body burns in a 24-hour period, including everything from keeping your heart beating to your morning workout.

Why TDEE matters: It's the single most useful number in any nutrition or fitness plan. Eat below it → lose weight. Eat above it → gain weight. Eat at it → maintain. Most diet failures come from not knowing this number accurately.

The four things TDEE includes

TDEE isn't one thing, it's the sum of four different ways your body uses energy:

1. BMR: Basal Metabolic Rate (60-70% of TDEE)

The calories your body burns just to stay alive. Your heart, lungs, brain, kidneys, and immune system all run 24/7 and they all need fuel. This is the biggest single chunk of TDEE.

BMR is determined mostly by body size and composition. Men typically have higher BMR than women due to more lean muscle mass. Larger bodies have higher BMR than smaller ones. Younger adults have slightly higher BMR than older ones.

2. TEF: Thermic Effect of Food (~10% of TDEE)

Your body uses calories to digest the food you eat. About 10% of every meal's calories go to processing the meal itself. Protein has the highest TEF (20-30% of protein calories are spent digesting it), carbs are middle (5-10%), and fats are lowest (0-3%). This is one reason high-protein diets feel slightly more "filling", your body literally spends more calories breaking it down.

3. NEAT: Non-Exercise Activity Thermogenesis (highly variable, often 15-30% of TDEE)

Every movement that isn't deliberate exercise. Walking to the kitchen, fidgeting in your chair, gesturing while you talk, standing up, taking the stairs, carrying groceries, picking up your kid. This category varies enormously between people, and within the same person on different days.

NEAT is also the first thing your body cuts when you're in a calorie deficit. When you're tired and hungry, you fidget less and sit more. This is one of the main reasons weight loss slows down on a diet, your unconscious movement drops without you noticing.

4. EAT: Exercise Activity Thermogenesis (varies by your training)

Your gym sessions, runs, sports, deliberate cardio. Most people overestimate this category dramatically. A typical 60-minute weightlifting session burns 200-400 calories. A 30-minute run burns 200-350. These numbers are smaller than the calorie counts shown on cardio machines (which are notoriously inflated).

How to calculate your TDEE

The standard formula is two steps:

Step 1: Calculate BMR using Mifflin-St Jeor

The Mifflin-St Jeor equation, published in 1990, is the gold standard for the general population:

Men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161

Step 2: Multiply by your activity multiplier

1.2, Sedentary (desk job, no exercise)
1.375, Light activity (1-3 light workouts/week)
1.55, Moderate (3-5 workouts/week)
1.725, Active (6-7 hard workouts/week or manual labor)
1.9, Very active (pro athlete, two-a-days)

If you'd rather skip the math, our free TDEE calculator does this in one step. It also gives you targets for cutting, maintaining, and lean bulking based on the result.

How to use your TDEE

For fat loss

Eat 15-25% below TDEE. A mild deficit (15%) gives roughly 1 lb/week of fat loss. An aggressive deficit (25%) gives roughly 2 lbs/week. Going more aggressive than 25% backfires for most people, too much hunger, too much muscle loss, too high a chance you break the diet.

For muscle gain

Eat 5-15% above TDEE. A "lean bulk" of +10% gives roughly 0.5 lb/week of weight gain. Most of that should be muscle if you're training hard with adequate protein (~1g per lb of bodyweight). Going much higher than +15% just adds fat without adding more muscle.

For maintenance

Eat at TDEE. Use this to lock in a new bodyweight after a cut or bulk, recover from a hard training block, or set a baseline before starting a new diet.

How accurate is the TDEE number?

TDEE estimates from formulas like Mifflin-St Jeor are accurate within about ±10% for most people. That's enough to start with. The real test is reality: track your weight for 2-3 weeks while eating your calculated TDEE.

If your weight is stable, your real TDEE matches the estimate.
If you're losing weight, your real TDEE is higher, eat more.
If you're gaining weight, your real TDEE is lower, eat less.

Adjust by ±100-200 calories based on what you see, and recalculate every 5-10 lbs of weight change since your TDEE moves as your body size moves.

For more on this, see our deep dive on how accurate TDEE calculators really are.

Common mistakes

Picking the wrong activity level

This is the single biggest source of error. Most desk workers who lift 3-4 times per week should pick "Light" (1.375), not "Active" (1.725). Active is for people doing manual labor or daily intense training. See our activity level guide for clearer examples.

Not adjusting as you change

Your TDEE drops as you lose weight (smaller body burns less). Recalculate every 5-10 lbs of change.

Trusting cardio machine calorie counts

Treadmills, ellipticals, and stationary bikes typically overestimate calories burned by 30-50%. Don't add their numbers on top of your TDEE, your activity multiplier already accounts for this.

Confusing TDEE with BMR

BMR is just the resting portion. Eating at BMR puts you in a steep deficit that's hard to sustain. Always use TDEE as your baseline. More on the difference here: TDEE vs BMR.

Try it now

Get your TDEE in 30 seconds with our free TDEE calculator. No signup, no email, just enter your sex, age, height, weight, and activity level.