TDEE Calculator &
BMR Calculator

What Is TDEE?

TDEE (Total Daily Energy Expenditure) is the total number of calories your body burns over a full day — everything from keeping your heart beating at rest to running a 5K. It is the single most important number in nutrition science because it defines your energy balance: eat below your TDEE to lose weight, above it to gain, and at it to maintain.

TDEE is calculated by multiplying your Basal Metabolic Rate (BMR) by an activity factor that accounts for how much you move. A sedentary office worker might burn 1.2× their BMR, while a construction worker who also trains daily might burn 1.9×.

What Is BMR?

BMR (Basal Metabolic Rate) is the calories your body burns at complete rest to sustain life — breathing, circulation, temperature regulation, and cellular repair. It represents 60–75% of TDEE for most sedentary people. Even if you stayed in bed all day without moving, your body would still burn your BMR in calories.

BMR is influenced by age (decreases ~1–2% per decade after 20), sex (men typically have higher BMR due to greater muscle mass), body weight, height, and lean muscle mass. Building muscle increases your BMR because muscle tissue burns more calories at rest than fat tissue.

What Is the Mifflin-St Jeor Formula?

The Mifflin-St Jeor equation, developed in 1990, is considered the most accurate formula for estimating resting metabolic rate in both obese and non-obese adults by the Academy of Nutrition and Dietetics. It accounts for weight, height, age, and sex:

Men:   BMR = (10 × weight_kg) + (6.25 × height_cm) − (5 × age) + 5
Women: BMR = (10 × weight_kg) + (6.25 × height_cm) − (5 × age) − 161

TDEE = BMR × Activity Multiplier

Calorie Deficit for Weight Loss

To lose body fat, you need to consume fewer calories than your TDEE — creating a calorie deficit. One kilogram of body fat contains approximately 7,700 calories. A daily deficit of 500 calories therefore produces roughly 0.5 kg of fat loss per week, which is widely considered the safe and sustainable rate.

Aggressive deficits (>750–1,000 kcal/day) accelerate scale weight loss but risk losing muscle mass alongside fat, nutritional deficiencies, hormonal disruption, and metabolic adaptation — where your body downregulates TDEE in response to restricted intake. Pairing a moderate deficit with adequate protein intake (1.6–2.2g/kg) and resistance training minimises muscle loss.

Calorie Surplus for Muscle Gain

Building muscle requires both adequate protein and a small calorie surplus above TDEE. A surplus of 250–500 kcal/day provides energy for muscle protein synthesis without excessive fat accumulation. This is often called a "lean bulk." Larger surpluses ("dirty bulking") produce faster scale weight gains but a significant proportion comes from fat, requiring a longer cut phase afterward.

Beginners and those returning from a training break can gain muscle even in a small deficit or at maintenance — a phenomenon called body recomposition. For experienced lifters, a genuine surplus is typically required to make meaningful muscle mass gains.

Maintenance Calories Explained

Your maintenance calories are simply your TDEE — the point at which calorie intake exactly matches calorie expenditure. Eating at maintenance results in no change in body weight over time (accounting for water fluctuations). Maintenance is a useful target for body recomposition (losing fat and gaining muscle simultaneously) and for periods of training that don't have a weight change goal.

Common TDEE Mistakes

Frequently Asked Questions