Calorie Counter

What Is a TDEE Calculator?

TDEE stands for Total Daily Energy Expenditure — the total number of calories your body burns in an average day, accounting for your base metabolism plus all physical activity. Knowing your TDEE is the foundation of evidence-based weight management: eat at your TDEE to maintain weight, eat below it to lose weight, and eat above it to gain weight.

This free calorie counter calculates your TDEE using the Mifflin-St Jeor equation, which is considered the most accurate formula for estimating caloric needs in non-athletic adults. It also shows your BMR (Basal Metabolic Rate — the calories burned at complete rest) and a range of calorie targets for different weight goals.

The Mifflin-St Jeor Formula Explained

The Mifflin-St Jeor equation calculates BMR as follows: for men, BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) + 5. For women, BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) − 161. This BMR is then multiplied by an activity factor — ranging from 1.2 for a sedentary lifestyle to 1.9 for a very active one — to produce the TDEE.

The formula was validated in a 2005 study comparing several BMR equations against measured resting energy expenditure in 498 participants, and was found to predict measured BMR within 10% for most people — making it the gold standard for general use. Other formulas such as the Harris-Benedict equation tend to overestimate caloric needs by 5–10%.

How to Use Your Results

Your TDEE (maintenance calories) is the number to target if you want to maintain your current weight. For weight loss, a deficit of 250–500 calories per day leads to a loss of approximately 0.25–0.5 kg per week — a sustainable, evidence-based pace that minimises muscle loss. For weight gain (typically for building muscle), a surplus of 250–500 calories per day supports gradual lean mass gain when combined with resistance training.

Larger deficits — more than 500–750 calories per day — accelerate weight loss but increase the risk of muscle loss, nutritional deficiencies, fatigue, and hormonal disruption. Very low calorie diets below 1,200 kcal for women or 1,500 kcal for men should only be undertaken under medical supervision.

Choosing the Right Activity Level

Sedentary applies if you have a desk job and do little or no structured exercise. Lightly active suits people who do light exercise 1–3 days per week, such as walking, yoga, or casual cycling. Moderately active is appropriate for those who do structured exercise like running, gym training, or team sports 3–5 days per week. Very active applies to people training intensively 6–7 days per week. Extremely active covers hard daily training combined with a physically demanding job.

Most people underestimate their activity level, but overestimating is also common — if results don't match your real-world experience after a few weeks, adjust the activity multiplier down and reassess.

Frequently Asked Questions

How accurate is this estimate?

The Mifflin-St Jeor formula is accurate within about 10% for most sedentary to moderately active adults. However, individual metabolic variation means some people burn significantly more or fewer calories than predicted. The best approach is to use this as a starting estimate, track your actual weight change over 2–3 weeks at the suggested calorie level, and adjust by 100–200 kcal based on what you observe.

Do I need to count calories every day?

Not necessarily. Some people find calorie tracking motivating and useful for learning portion sizes. Others find it stressful or unsustainable. Calorie counting can be most useful for a short period to build awareness of what you eat, after which many people can manage by portion control and general nutritional awareness without tracking every meal.

What about macronutrients?

Total calories determine weight change, but the macronutrient split (protein, carbohydrates, fat) affects body composition, satiety, energy levels, and performance. A common guideline for fat loss while preserving muscle is 1.6–2.2g of protein per kg of body weight per day, with the remainder of calories split between carbohydrates and fats according to preference and activity type.

Does metabolism slow down with age?

Yes — BMR decreases by approximately 1–2% per decade after age 20, largely due to the gradual loss of muscle mass that comes with aging. This is why maintaining or building muscle through resistance training becomes increasingly important for weight management as people get older, as muscle tissue is metabolically more active than fat tissue.

Practical Tips for Hitting Your Calorie Target

Use a food diary or app to track intake for a few weeks to build awareness. Focus on protein and fibre at each meal — both increase satiety and help control appetite. Plan meals in advance to avoid making high-calorie choices when hungry. Liquid calories from alcohol, juice, and sweetened drinks are easy to overlook and can significantly undermine a deficit. And be patient — sustainable results come from consistent habits over weeks and months, not dramatic short-term restrictions.