QuickBestGo
EN

Calorie Calculator

How does the Calorie Calculator work?

The Calorie Calculator estimates your daily energy needs using the Mifflin-St Jeor equation, the formula most widely recommended by registered dietitians and the Academy of Nutrition and Dietetics. Published in 1990, it calculates your Basal Metabolic Rate (BMR) — the minimum calories your body needs to sustain vital functions at complete rest, including breathing, circulation, cell repair, and temperature regulation. The formula uses different coefficients for men and women to account for differences in typical body composition.

Your BMR is multiplied by an Activity Factor to estimate your Total Daily Energy Expenditure (TDEE) — the total calories you burn each day including all physical activity. Activity levels range from Sedentary (factor 1.2, for desk workers with little exercise) to Extra Active (factor 1.9, for people with physically demanding jobs plus intense daily training). The result is the number of calories required to maintain your current weight. Eating below this number creates a calorie deficit; eating above it creates a surplus.

To lose weight safely and sustainably, aim for a deficit of 300–500 kcal per day, which corresponds to approximately 0.3–0.5 kg of fat loss per week. To gain weight or build muscle, add 250–500 kcal above your TDEE. These are evidence-based starting estimates — individual results vary based on genetics, hormonal factors, sleep quality, stress levels, and medication. The best approach is to use this calculator as a baseline, track your actual body weight over 2–3 weeks, and adjust your intake accordingly based on real-world results.

How to Use the Calorie Calculator

  1. 1

    Select your biological sex (Male or Female). The Mifflin-St Jeor formula uses different coefficients for men and women.

  2. 2

    Enter your age in years. Metabolism naturally slows with age, and the formula accounts for this change.

  3. 3

    Enter your height in centimeters and your current weight in kilograms.

  4. 4

    Select the activity level that best matches your typical weekly routine — be honest and conservative; most people overestimate their activity.

  5. 5

    Click Calculate to see both your BMR (calories at complete rest) and your TDEE (total daily calories needed).

  6. 6

    Use your TDEE as your calorie target: eat at TDEE to maintain weight, below to lose, or above to gain.

Frequently Asked Questions

What is the Mifflin-St Jeor equation?
The Mifflin-St Jeor equation estimates BMR as follows — For men: (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5. For women: (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161. It is more accurate than the older Harris-Benedict equation and is the standard recommended by most nutrition and dietetics organizations.
What is the difference between BMR and TDEE?
BMR (Basal Metabolic Rate) is the calories your body burns at complete rest — just to keep you alive. TDEE (Total Daily Energy Expenditure) includes all your daily activity on top of BMR. Your TDEE is the practical number to use when planning your diet, not your BMR.
How many calories should I eat to lose weight?
A safe and sustainable weight loss pace is 0.5–1 kg per week, achieved through a daily calorie deficit of approximately 500–1000 kcal below your TDEE. Eating below 1200 kcal/day for women or 1500 kcal/day for men is not recommended without medical supervision, as it risks nutrient deficiencies and muscle loss.
How accurate is this calorie calculator?
The Mifflin-St Jeor equation is accurate to within roughly 10% for most healthy adults. Actual calorie needs vary with individual metabolism, body composition, hormonal status, medications, and other factors. Use the result as a starting estimate and adjust based on 2–3 weeks of real-world weight tracking.
What activity level should I choose?
Choose the level that reflects your average typical week, not your best week. Sedentary means a desk job with minimal movement. Lightly active means light exercise 1–3 days per week. Moderately active means 3–5 days of exercise. Very active means hard exercise 6–7 days. Extra active means physically demanding work plus intense daily training. When in doubt, select one level lower than you think.
Should I eat my BMR or my TDEE calories?
You should plan your diet around your TDEE, not your BMR. Your BMR is the minimum your body needs just to stay alive at complete rest. Eating at or below BMR for extended periods is harmful — it can slow your metabolism, cause muscle loss, and lead to nutritional deficiencies.
Does this calculator work for weight gain and muscle building?
Yes. To build muscle and gain weight, eat 250–500 kcal above your TDEE. A smaller surplus of 250–300 kcal is better if you want to minimize fat gain. Pairing a calorie surplus with a structured strength training program gives significantly better results than diet alone.
Is the data I enter stored or shared?
No. All calculations are performed entirely within your browser. Your age, sex, height, weight, and activity data are never transmitted to any server or stored in any form.