TDEE Calculator

Last updated: 2026-05-22

Total daily energy expenditure

Total daily energy expenditure (TDEE) is the number of calories the body uses in a day, combining the energy spent at rest with the energy spent on all physical activity. It is the reference point for nutrition planning: eating at TDEE keeps weight stable, eating below it produces a deficit that drives weight loss, and eating above it produces a surplus that supports weight or muscle gain.

This calculator estimates TDEE from body metrics and activity level, applies a calorie goal, and splits the resulting target into a macronutrient breakdown (protein, fat, carbohydrate).

Mechanism

TDEE is built from two parts. The first is basal metabolic rate (BMR) — the energy the body uses at complete rest to sustain breathing, circulation, cell maintenance, and temperature. BMR accounts for the majority of daily energy use for most people. The second is everything layered on top of rest: exercise, walking, and the low-level movement of daily life.

TDEE is the product of BMR and an activity factor:

$\text{TDEE} = \text{BMR} \times \text{Activity Factor}$

BMR itself is estimated with the Mifflin-St Jeor equation, the published formula that most closely matches measured resting metabolism in typical adults:

$\text{BMR} = 10w + 6.25h - 5\,\text{age} + s$

In this equation, $w$ is weight in kilograms, $h$ is height in centimetres, age is in years, and $s$ is a constant term set by biological sex (5 for males, −161 for females). Resting metabolism declines with age — roughly 5 kcal/day per year through the age term — and rises with body mass and height.

The activity factor converts a typical week into a single multiplier:

Self-reported activity tends to run high: when self-reports are validated against pedometers and heart-rate monitors, most people fall one tier below the level they select. The factor below the apparent fit is often the more accurate choice.

Macronutrient split

The diet plan selector fixes the share of calories from protein, fat, and carbohydrate. Each plan distributes the daily calorie target across the three macronutrients, which the calculator then converts to grams using the energy density of each (protein and carbohydrate at 4 kcal/g, fat at 9 kcal/g).

Across every plan the protein target generally lands in the 1.6–2.2 g per kg of body weight0.7–1.0 g per pound of body weight range, which the sports-nutrition literature (Schoenfeld & Aragon, 2018; ISSN position stand) identifies as the range for preserving or building muscle, in both deficit and surplus.

Worked example

Consider a 30-year-old male, 80 kg, 180 cm tall, training moderately (factor 1.55), aiming for a 500 kcal deficit on the high-protein plan.

BMR is $10 \times 80 + 6.25 \times 180 - 5 \times 30 + 5 = 800 + 1125 - 150 + 5 = 1780$ kcal/day. TDEE is $1780 \times 1.55 \approx 2759$ kcal/day. The 500 kcal deficit gives a daily target of about 2259 kcal. On the high-protein 40/30/30 split, that is roughly 904 kcal from protein (226 g), 678 kcal from fat (75 g), and 678 kcal from carbohydrate (170 g). The 226 g of protein works out to about 2.8 g/kg — at the upper end of the cited range for a person in a deficit.

Variations and limits

• Individual variance is real. Predicted BMR can differ from indirect calorimetry by up to ±20%. The output is a starting hypothesis, not a measurement; weight movement over two to four weeks reveals the true figure.
• The activity factor is coarse. The gap between moderate (1.55) and active (1.725) is 11%, or about 275 kcal on a 2,500-kcal day. A wearable that estimates active calories gives a tighter answer than the lookup table.
• NEAT is not captured. Non-exercise activity thermogenesis — fidgeting, posture, spontaneous walking — varies substantially between individuals (Levine et al., 2005) and is not represented by the activity tiers. It is a common reason two people with the same routine maintain different weights.
• Macro splits are general guidelines. The 30/30/40 default suits most healthy adults, but competitive athletes, people with diabetes or kidney disease, and anyone following a specific protocol (ketogenic, plant-based) need different ratios.

Application

For fat loss, a deficit of 300–500 kcal/day below TDEE is sustainable for most people; about half a kilogram of fat per week, using the rough 7,716 kcal per kg figureabout a pound of fat per week, using the rough 3,500 kcal per pound figure. Steeper deficits accelerate loss but raise the risk of losing lean mass and intensify the metabolic adaptation that makes a diet progressively harder.

For muscle gain, a surplus of 200–500 kcal/day combined with progressive resistance training is typically sufficient. Larger surpluses add fat without proportionally more muscle, because daily muscle protein synthesis has a ceiling.

To calibrate a maintenance figure, set the goal to maintenance, hold the target for one to two weeks, and track body weight as a weekly average to filter daily noise. Stable weight confirms the estimate; a steady drift indicates the offset between the prediction and the true figure (× 7,700 kcal/kg)(× 3,500 kcal/lb). The calculator provides the starting estimate; actual weight, body composition, and performance over time refine it.