TDEE stands for Total Daily Energy Expenditure. It tells you how many calories you burn in a day, from the energy your body uses at rest to keep you alive, to the calories you burn through physical activity and digesting food.

Knowing your TDEE helps you understand how much to eat to maintain, lose, or gain weight.

Your TDEE is made up of three components:

• Basal Metabolic Rate (BMR) accounts for around 60–70% of your total daily burn. This covers essential functions like breathing, circulating blood, and cell repair. It's the largest part of your TDEE and is mainly determined by your age, sex, height, and weight.
• Physical activity makes up around 15–30% and is the most variable component. It includes structured exercise as well as everyday movement like walking, standing, and household tasks.This everyday movement is sometimes called NEAT. Two people of the same height and weight can have very different TDEEs depending on how active their day is.
• Thermic effect of food accounts for roughly 10%. This is the energy your body uses to digest, absorb, and process what you eat. Protein-rich foods require more energy to digest than fats or carbohydrates.

TDEE is calculated in two steps. First, we estimate your Basal Metabolic Rate (BMR), the calories your body burns at rest. Then we multiply that by an activity factor based on how active you are.

We use the Mifflin-St Jeor equation, which research has shown to be the most accurate method for estimating BMR.

The formula:

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

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

TDEE = BMR × activity factor

Most TDEE calculators in the UK ask you to pick a single activity level from a dropdown, like "moderately active" or "very active." The problem is that most people pick too high. Research shows that many people overestimate how active they are, which leads to an inflated TDEE and a smaller calorie deficit than they think.

Our calculator works differently. Instead of one dropdown, we ask two separate questions: what your typical day looks like (sitting, standing, walking, or physical work) and how often you exercise. Combining these two answers gives a more realistic picture of your actual activity level.

Your TDEE is the number of calories you need to eat each day to stay at your current weight. Think of it as your daily calorie budget.

To lose weight, you need to eat fewer calories than your TDEE. A deficit of around 500 calories per day leads to roughly 0.5 kg of weight loss per week. Don't go below 1,200 cal/day (women) or 1,500 cal/day (men) without medical advice.

To gain weight, eat more than your TDEE. Start with a modest surplus of 250 to 500 calories per day and adjust based on your progress.

To maintain your weight, eat roughly the same as your TDEE. Your weight will fluctuate day to day, but your long-term average should stay stable.

As a rough guide, 1 kg of body fat contains approximately 7,700 calories. So a deficit of 500 calories per day adds up to around 3,500 per week, which works out at roughly 0.5 kg of weight loss. These figures are estimates and may vary between individuals.

TDEE calculators provide estimates, not exact measurements. The Mifflin-St Jeor equation we use has been shown to predict how many calories your body burns at rest within 10% of measured values in the majority of people.

The biggest source of error is the activity level. Research shows that a large proportion of people overestimate how active they are, which is why we redesigned the activity assessment from scratch. Instead of asking you to choose between labels like "sedentary", "lightly active", or "very active", we ask two separate questions: what your typical day looks like and how often you exercise. This gives a more realistic estimate than the single dropdown used by most calculators.

Use your TDEE as a starting point and adjust based on your progress over 2 to 4 weeks. If your weight isn't changing as expected, revisit your activity answers.

BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest, just to keep you alive. It covers essential functions like breathing, circulating blood, and cell repair.

TDEE (Total Daily Energy Expenditure) is your total daily calorie burn. It includes your BMR plus everything else: structured exercise, everyday movement like walking and standing (sometimes called NEAT), and digesting food.

The key difference is that BMR only measures what your body needs at rest, while TDEE reflects what you actually burn in a real day. For example, someone with a BMR of 1,400 cal/day could have a TDEE of 1,700 to 2,400 depending on how active they are.

No. Your TDEE already includes your exercise. When you told us how often you work out, we factored that into your result.

For example, if your TDEE is 2,000 cal/day, that 2,000 already accounts for your workouts. If you're eating 1,500 for a 500-calorie deficit, but then eat an extra 300 after the gym to "make up" for what you burned, your actual deficit drops to 200. You'll still lose weight, just much slower than expected.

To lose weight, you need to eat fewer calories than your TDEE. How much fewer depends on how quickly you want to lose weight.

A deficit of 250 cal/day leads to roughly 0.25 kg of weight loss per week. A deficit of 500 cal/day leads to roughly 0.5 kg per week. Larger deficits can produce faster results but are harder to sustain.

Don't go below 1,200 cal/day (women) or 1,500 cal/day (men) without medical advice. Eating too little can slow your metabolism, increase hunger, and leave you short on essential nutrients.

The most effective deficit is one you can actually stick to. A smaller deficit you maintain consistently will always beat a large one you abandon after two weeks.

The most common reason is that your deficit is smaller than you think. This usually comes down to one or both of the following:

You may be eating more than you realise. Sauces, dressings, cooking oils, and drinks can add hundreds of calories without feeling like a meal. Try tracking everything you eat and drink for 1 to 2 weeks to get an accurate picture.

You may be less active than you were. A dip in daily steps, fewer gym sessions, or a change in routine can lower your TDEE without you noticing. Revisit your activity answers if your lifestyle has shifted.

Your TDEE may have changed. As you lose weight, your body burns fewer calories because there is less of you to fuel. If you've lost 5% or more of your body weight since you last used the calculator, recalculate your TDEE. What was a 500-calorie deficit at the start may now be closer to maintenance.

If you've hit a weight loss plateau lasting more than 4 weeks despite consistent effort, speak to a healthcare professional. There may be other factors at play, including hormonal changes or medication effects.

BMI (Body Mass Index) measures your weight relative to your height. It helps you understand whether you may benefit from losing weight, gaining weight, or maintaining where you are, and whether your current weight may be increasing your risk of conditions like type 2 diabetes, high blood pressure, or heart disease.

TDEE then helps you act on that. Once you know your goal, your TDEE tells you how many calories to eat each day to get there.

If you haven't already, try our BMI calculator to see where you stand.

If you're finding it difficult to maintain a calorie deficit through diet and lifestyle changes alone, you're not alone. For many people, the challenge isn't knowing what to eat. It's managing hunger and cravings consistently enough to stay in a deficit long term.

Prescription weight loss medications like Wegovy (semaglutide) and Mounjaro (tirzepatide) are GLP-1 receptor agonists. They work by reducing appetite and quieting "food noise", the constant background urge to eat. This makes it easier to eat less than your TDEE without relying on willpower alone.

Voy members lose an average of 21.5% of their body weight in 10 months. This is based on a clinical study of 57,975 participants, conducted in partnership with Imperial College London.