TDEE Calculator

Worked Example — 30-year-old Male, 75 kg, 175 cm, Moderately Active

Step 1 — BMR (Mifflin-St Jeor, male):
BMR = 10 × 75 + 6.25 × 175 − 5 × 30 + 5
BMR = 750 + 1,093.75 − 150 + 5 = 1,698.75 ≈ 1,699 kcal/day

Step 2 — TDEE (Moderate activity multiplier 1.55):
TDEE = 1,699 × 1.55 = 2,633 kcal/day

Step 3 — Calorie targets:
Weight loss (−500): 2,133 kcal | Maintenance: 2,633 kcal | Weight gain (+500): 3,133 kcal

Step 4 — Macros at maintenance (2,633 kcal):
Carbs 40%: 2,633 × 0.40 ÷ 4 = 263 g | Protein 30%: 2,633 × 0.30 ÷ 4 = 197 g | Fat 30%: 2,633 × 0.30 ÷ 9 = 88 g

TDEE Reference Table — Estimated Values by Profile

All values computed using Mifflin-St Jeor BMR × activity multiplier. Heights and weights are illustrative mid-range examples.

BMR values computed with Mifflin-St Jeor: Male = 10W + 6.25H − 5A + 5; Female = 10W + 6.25H − 5A − 161. All kcal/day values rounded to the nearest whole number.

How the Formulas Work

Mifflin-St Jeor (1990) — Recommended Default

Harris-Benedict Revised (Roza & Shizgal, 1984)

Activity Multipliers (Katch-McArdle / Harris-Benedict classification)

The Four Components of TDEE

Your TDEE is not a single process — it is the sum of four separate ways your body spends energy across a day. Understanding the pieces explains why two people of the same size can have very different real-world calorie needs, and where you actually have leverage.

Two facts surprise most people. First, BMR dominates — roughly two-thirds of everything you burn happens while you are doing nothing at all, simply staying alive. Second, NEAT is the wild card. The energy you spend walking to the shops, taking the stairs, cooking, fidgeting and standing can differ by hundreds — even up to a couple of thousand — of calories per day between two similar people, and the body quietly turns NEAT down when you diet (you move less without noticing). Deliberate exercise (EAT), by contrast, is usually a smaller slice than expected: a hard 45-minute gym session might burn 300–400 calories, which a single large meal can erase. This is why "you cannot out-train a bad diet" is broadly true, and why staying generally active all day often matters more than the workout itself.

BMR Formulas That Use Body Fat: Katch-McArdle

The Mifflin-St Jeor and Harris-Benedict equations only use weight, height, age and sex. They cannot tell the difference between two people of the same weight where one is lean and muscular and the other carries more fat — yet muscle is far more metabolically active than fat, so their true BMRs differ. If you know your body-fat percentage (from a DEXA scan, calipers, or a smart scale), a formula based on lean body mass (LBM) can be more accurate, especially for athletes and very muscular or very lean individuals.

Katch-McArdle Equation

Notice it has no separate male/female version — by working directly from lean mass, the formula already captures the body-composition differences that the sex constant stands in for elsewhere. A closely related option, the Cunningham equation (BMR = 500 + 22 × LBM), tends to read a little higher and is often preferred for lean athletes.

Worked example. A person weighing 80 kg at 20% body fat has a lean body mass of 80 × (1 − 0.20) = 64 kg. Their Katch-McArdle BMR is 370 + 21.6 × 64 = 1,752 kcal/day. Enter your body-fat percentage in the calculator above and it computes both the Katch-McArdle and Cunningham BMR for you — and the TDEE Formula selector lets you base your TDEE and calorie targets on either one. If you do not know your body-fat percentage, stick with the Mifflin-St Jeor result this calculator shows by default — it is the most reliable choice for the general population.

The Science of a Calorie Deficit and Surplus

Body weight changes when energy intake and energy expenditure fall out of balance. Eat below your TDEE and you create a deficit, forcing your body to draw on stored energy (mostly fat) to make up the difference. Eat above it and the surplus is stored, as fat and — with resistance training and enough protein — as muscle.

The rough conversion used by nutritionists is that about 7,700 kcal is stored in one kilogram of body fat (roughly 3,500 kcal per pound). So a steady 500-calorie daily deficit theoretically removes about 0.5 kg of fat per week (500 × 7 = 3,500 kcal):

• −250 kcal/day ≈ 0.25 kg/week (gentle, easiest to sustain)
• −500 kcal/day ≈ 0.5 kg/week (the standard recommendation)
• −1,000 kcal/day ≈ 1 kg/week (aggressive; harder to keep up and risks muscle loss)

In the real world the scale rarely matches the maths exactly, for honest physiological reasons. In the first week of a diet, weight often drops faster than the calorie sums predict, because the body sheds water and glycogen, not just fat. Later, weight loss tends to slow: as you get lighter your BMR falls (a smaller body needs fewer calories), and your body defends itself through adaptive thermogenesis — resting metabolism can drop by 10–15% beyond what the size change alone explains, and NEAT quietly declines as you feel less energetic. This is the normal mechanism behind the dreaded weight-loss plateau, and it is why a target that worked at the start may need to be recalculated as you progress.

A sensible, sustainable rate of loss is roughly 0.5–1% of your body weight per week. Most professionals advise not eating below about 1,200 kcal/day for women or 1,500 kcal/day for men without medical supervision, both to protect nutrition and to limit muscle loss.

How to Use Your TDEE — A Practical 5-Step Method

The calculated number is an excellent starting estimate, not a verdict. Treat it as hypothesis number one and let the bathroom scale refine it:

• 1. Pick your goal calories. Eat at maintenance to hold weight, subtract 250–500 to lose, or add 250–500 to gain. Pick the gentler end if you are new to tracking.
• 2. Track honestly for 2–3 weeks. Weigh and log your food, and weigh yourself in the same conditions (morning, after the toilet, before eating). Single-day weights are noisy — watch the weekly average.
• 3. Compare the trend to the prediction. If your weight is stable, you have found your real maintenance level — which may differ from the formula by 10–20%. If it is moving the wrong way, the estimate was off for you.
• 4. Adjust by 100–200 kcal and reassess over another two weeks. This feedback loop, not the formula, is what actually works.
• 5. Recalculate as your weight changes. Lose or gain 5–8 kg and your TDEE shifts, because BMR scales with body size. Re-run the numbers every few weeks.

Protein, Satiety and Preserving Muscle

Total calories decide whether you gain or lose weight, but the composition of those calories decides whether you keep your muscle and how full you feel. Protein does three useful jobs at once. It has the highest thermic effect of any macronutrient — your body burns roughly 20–30% of protein's calories just digesting it, versus 5–10% for carbohydrate and 0–3% for fat — so a high-protein diet nudges TDEE upward. It is the most satiating macronutrient, which makes a calorie deficit easier to tolerate. And in a deficit it is the signal that tells your body to burn fat rather than break down muscle for fuel.

A common, well-supported target is 1.6–2.2 grams of protein per kilogram of body weight per day when you are losing weight or training to build muscle. Pair adequate protein with resistance exercise and you can lose fat while largely preserving — or even gaining — muscle, which keeps your metabolism higher and your physique firmer than dieting on calories alone. The remaining calories are best filled with fibre-rich carbohydrates and healthy fats, which support energy, hormones and digestion.

How Accurate Are These Estimates?

Predictive BMR equations are population averages, and even the best of them — the Mifflin-St Jeor — only lands within about 10% of laboratory-measured resting energy expenditure for roughly four in five people. That means your true maintenance level could realistically sit a couple of hundred calories above or below the figure shown here. The estimates are least reliable for people whose body composition is far from average, including very muscular athletes, people with a high body-fat percentage, the elderly, pregnant or breastfeeding women, and children and teenagers, whose needs are different again.

None of that makes the calculator useless — it makes it a starting point you then calibrate against reality. Use the number to set an initial target, track for a few weeks, and trust the trend on the scale over any formula. And because these are statistical estimates rather than medical advice, anyone with a health condition, an eating disorder history, or significant weight to lose or gain should speak to a registered dietitian or physician before making big changes.

Common Mistakes With TDEE Calculators

A TDEE estimate only helps if you sidestep the handful of errors that quietly sabotage it:

• Overstating your activity level. This is by far the most common mistake. A few gym sessions a week is "lightly" to "moderately" active, not "very active". An honest desk-worker who trains three times a week is usually moderate (×1.55), and an inactive office job is genuinely sedentary (×1.2). When unsure, pick the lower level — you can always eat a little more if you find you are losing weight too quickly.
• Double-counting exercise. The activity multiplier already includes your workouts. If you then "eat back" the calories a fitness tracker says you burned in the gym, you are counting that energy twice — a frequent reason a diet stalls.
• Trusting wearable calorie burns. Fitness watches are notoriously inaccurate for energy expenditure, often overestimating by 20–30%. Use them for trends, not as a calorie budget.
• Never recalculating. Your TDEE falls as you lose weight, so a target set at your starting weight becomes too high months later — part of why plateaus appear if you never revisit the numbers.
• Chasing a too-aggressive deficit. Slashing calories drastically backfires: it accelerates muscle loss and metabolic slowdown, and a crash diet is far harder to sustain than a moderate deficit you can hold for months.