Calorie Calculator (TDEE)
Estimate your daily calorie needs to maintain, lose or gain weight.
Estimates using the Mifflin-St Jeor equation. Not medical advice.
Understanding Your Daily Calorie Needs
A calorie calculator estimates how many calories your body needs each day to function and stay at your current weight. This figure is called your Total Daily Energy Expenditure, or TDEE. It combines the energy your body uses at complete rest with the energy burned through movement, exercise, and digestion. Knowing your TDEE is the foundation for any weight goal, whether you want to maintain, lose, or gain weight in a sensible way.
Calorie needs are personal. They depend on your age, sex, height, weight, and how active you are. A tall, active young person burns far more than a shorter, sedentary older person, which is why generic numbers like "2,000 calories a day" are only rough averages. This calculator tailors the estimate to you. Once you know your number, you can plan meals with confidence instead of guessing, making it far easier to reach a weight goal steadily and sustainably rather than through crash diets that rarely last.
The Mifflin-St Jeor Formula
The calculation starts with your Basal Metabolic Rate (BMR), the calories you would burn if you rested all day. The widely trusted Mifflin-St Jeor equation is:
Men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) + 5
Women: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) − 161
Once you have BMR, multiply it by an activity factor to get TDEE:
Sedentary (little exercise) = 1.2 · Lightly active (1–3 days/week) = 1.375 · Moderately active (3–5 days/week) = 1.55 · Very active (6–7 days/week) = 1.725 · Extra active (hard daily training or physical job) = 1.9
A Worked Example
Consider a 30-year-old woman who weighs 65 kg, stands 165 cm tall, and exercises moderately about four days a week.
BMR = (10 × 65) + (6.25 × 165) − (5 × 30) − 161
BMR = 650 + 1,031.25 − 150 − 161 = 1,370 calories
Now apply the moderately active factor of 1.55:
TDEE = 1,370 × 1.55 = 2,124 calories per day
This is roughly what she needs to maintain her current weight. Eating consistently above or below this number shifts her weight up or down over time.
Calories for Maintaining, Losing, or Gaining
Your TDEE is the maintenance level. To lose weight, eat fewer calories than you burn; a common, gentle deficit is about 500 calories per day, which often supports losing around half a kilogram per week. To gain weight, particularly muscle, add roughly 300 to 500 calories per day alongside strength training.
Using the example above, the woman would aim for about 1,624 calories to lose weight or about 2,524 calories to gain. It is wise not to drop too low; very aggressive deficits can leave you tired and may be hard to sustain.
Quality matters as much as quantity. The same calorie count can come from nutrient-rich foods or from empty calories, and the two affect your energy, hunger, and health very differently. Prioritising adequate protein, plenty of vegetables, whole grains, and healthy fats helps you feel full and preserve muscle while in a deficit. Staying hydrated and getting enough sleep also influence appetite and how your body uses energy.
These figures are estimates, so adjust them based on real-world results over a few weeks rather than expecting them to be exact from day one. If the scale is not moving as expected, small tweaks of 100 to 200 calories are usually enough. For personalised guidance, especially if you have a health condition, are pregnant, or have specific performance goals, consider speaking with a registered dietitian or doctor who can tailor a plan to your individual needs.
Frequently Asked Questions
The Mifflin-St Jeor formula is one of the most reliable estimates available, but it is still an approximation. Real calorie needs vary with muscle mass, hormones, and individual metabolism. Treat the result as a starting point, track your weight and energy over two to three weeks, and fine-tune your intake based on what actually happens.
Your BMR only covers the energy used at rest. Activity, from daily walking to workouts, can add a large share of your total burn. The activity factor scales your BMR up to reflect this, so being honest about how active you really are gives you a more accurate daily calorie figure.
Very low intakes can lead to fatigue, nutrient gaps, and muscle loss, and they are often difficult to maintain. A moderate deficit of around 500 calories a day is gentler and more sustainable. If you are considering a significant calorie restriction, it is best to discuss it with a doctor or registered dietitian first.
A daily deficit of about 500 calories below your TDEE is a common, sustainable target that often supports losing roughly half a kilogram per week. Larger deficits can speed results but are harder to stick to. The healthiest pace is one you can maintain consistently over months.
Generally yes. The Mifflin-St Jeor formula uses a different constant for men and women, reflecting average differences in body composition and muscle mass. This is why men often have a higher BMR and TDEE than women of the same age, height, and weight.
Yes. As your weight changes, so does your BMR and TDEE. Recalculating every few kilograms, or roughly once a month during a weight goal, keeps your target accurate. Stalled progress is often a sign that your needs have shifted and your intake should be adjusted.