TDEE Calculator

What Is TDEE and Why Does It Matter?

Your Total Daily Energy Expenditure (TDEE) is the single most important number in any nutrition plan. It represents the total calories your body burns over a 24-hour period — not just while exercising, but every breath, heartbeat, and step you take. Without knowing your TDEE, you are essentially guessing when it comes to calories, and that guesswork is why most diets fail.

When you eat at your TDEE, your weight stays stable. Eat below it, and you lose fat. Eat above it, and you gain mass. It is that simple in principle — and this calculator gives you an accurate, science-backed starting point so you can stop guessing and start making real progress.

How TDEE Is Calculated

TDEE is calculated in two steps: first estimate your Basal Metabolic Rate (BMR), then multiply it by an activity factor.

Step 1 — Calculate BMR

BMR is the number of calories your body burns at complete rest over 24 hours. This calculator uses two validated formulas:

Multiple studies have validated Mifflin-St Jeor as the more accurate formula for modern sedentary and moderately active individuals. Harris-Benedict tends to slightly overestimate BMR in less active populations, which is why it is provided as a secondary option.

Step 2 — Apply the Activity Multiplier

Once you have your BMR, multiply it by the factor that matches your typical weekly activity. The result is your TDEE — the number of calories that keeps your weight exactly stable.

• Sedentary (1.2): Office worker with no regular exercise
• Lightly active (1.375): Light exercise 1–3 days per week
• Moderately active (1.55): Exercise 3–5 days per week
• Very active (1.725): Hard training 6–7 days per week
• Extra active (1.9): Physical job or double training sessions

Understanding Your Calorie Goals

Once you know your TDEE, setting the right calorie target is straightforward. Here is how each deficit or surplus translates to real-world outcomes:

Mild Weight Loss (TDEE − 250 kcal)

A small, sustainable deficit of 250 calories per day leads to approximately 0.25 kg (half a pound) of fat loss per week. This approach minimises muscle loss and hunger, and is ideal for people who are already fairly lean or who prefer a gradual approach. Progress is slow but highly sustainable over months.

Weight Loss (TDEE − 500 kcal)

The classic 500-calorie deficit is the most widely recommended approach. It produces around 0.5 kg (1 lb) of fat loss per week while remaining manageable for most people. Combined with adequate protein intake and resistance training, most people preserve nearly all their muscle mass at this deficit level.

Aggressive Weight Loss (TDEE − 1000 kcal)

A deficit of 1000 calories per day targets approximately 1 kg (2 lbs) of weight loss per week. This is only advisable for individuals with a high TDEE (above 2500 kcal) so that enough calories remain to meet nutritional minimums. Very low-calorie intakes increase the risk of muscle loss, nutrient deficiencies, and rebound eating. This deficit should typically be time-limited to 6–12 weeks maximum.

Weight Gain (TDEE + 500 kcal)

For lean muscle gain, a modest surplus of 500 calories above TDEE is the standard recommendation. This supports muscle protein synthesis without excessive fat accumulation. Pair this with progressive resistance training and sufficient protein (at least 1.6 g per kg of body weight) to maximise muscle growth and minimise fat gain.

Macronutrients: Protein, Fat, and Carbs

Knowing your total calorie target is only half the picture. Macronutrient distribution — how you split those calories across protein, fat, and carbohydrates — has a major impact on body composition, satiety, and performance.

Protein

Protein is the most important macro for body composition. It preserves muscle during a deficit, supports muscle growth during a surplus, and has the highest thermic effect of any macronutrient (you burn roughly 25–30% of protein calories just digesting it). Our calculator uses a target of 1 gram of protein per pound of body weight, which aligns with a large body of sports science research showing this to be optimal for muscle preservation and growth in active individuals.

Fat

Dietary fat is essential for hormonal health, vitamin absorption, and cell membrane integrity. Dropping fat below 20% of total calories can impair testosterone production and recovery. Our calculator targets 0.4 grams of fat per pound of body weight as a sensible baseline. Adjust upward if you follow a lower-carb eating style.

Carbohydrates

After protein and fat are allocated, remaining calories are filled by carbohydrates. Carbs are the body's preferred fuel for high-intensity exercise and are not inherently fattening — eating too many total calories causes fat gain, not carbohydrates themselves. Athletes and people who exercise frequently will benefit from higher carbohydrate intakes.

Tips for Using Your TDEE Accurately

• Be honest about activity level. Research consistently shows people overestimate exercise output. When in doubt, choose the level below what you think you are.
• Track actual results. Weigh yourself daily and average the weekly results. If you are losing faster or slower than expected, adjust calories by 100–200 kcal.
• Recalculate every 4–6 weeks. As your weight changes, so does your TDEE. Recalculate regularly to keep your targets accurate.
• Account for non-exercise activity (NEAT). Fidgeting, walking around the house, and standing all contribute to TDEE but are hard to quantify. Track trends rather than relying on a single calculation.
• Prioritise protein. On any calorie target, protein intake is the variable that most determines whether you lose fat or muscle. Hit your protein goal every day before worrying about fat/carb ratios.