Calorie Calculator

Find out exactly how many calories you need each day using the scientifically validated Mifflin-St Jeor equation. Enter your age, gender, height, weight, and activity level to get your BMR, TDEE, and personalized calorie targets for weight loss or weight gain — free, no signup required.

Daily Calorie Calculator

What Is a Calorie Calculator?

A calorie calculator estimates how many calories your body needs each day to maintain, lose, or gain weight. The result depends on your unique combination of biometrics (age, sex, height, weight) and lifestyle (how active you are). This tool uses the Mifflin-St Jeor equation, which is widely regarded as the most accurate BMR estimation formula for most adults, as validated by multiple peer-reviewed studies.

Calories are units of energy. Your body needs a certain number of calories each day just to keep vital organs functioning — this baseline is your Basal Metabolic Rate (BMR). On top of BMR, you burn additional calories through physical movement and exercise. The combination of your BMR and activity-based calorie burn is your Total Daily Energy Expenditure (TDEE). Your TDEE is your maintenance calorie level: eat this amount and your weight stays roughly stable.

To lose weight, you create a calorie deficit by eating less than your TDEE. To gain weight (muscle, during a "bulk"), you eat in a calorie surplus. Understanding your personal calorie numbers is the most scientifically grounded foundation for any nutrition plan, whether your goal is fat loss, muscle building, athletic performance, or simply maintaining a healthy weight.

This calculator also shows targeted calorie levels for different rates of weight change. A 500-calorie daily deficit produces roughly 1 lb (0.45 kg) of fat loss per week — a pace considered safe and sustainable by most health authorities. A 250-calorie deficit gives a gentler pace of about 0.5 lb/week, which some people find easier to maintain long-term. Similarly, 500 calories above maintenance supports muscle gain during a resistance training program.

How to Use This Calorie Calculator

  1. Select your unit system — Imperial (feet, inches, lbs) or Metric (cm, kg).
  2. Enter your age — BMR decreases slightly with age as metabolism slows.
  3. Select your biological sex — males and females have different BMR formulas due to physiological differences in lean body mass.
  4. Enter your height — in feet and inches (Imperial) or centimeters (Metric).
  5. Enter your weight — your current body weight in lbs or kg.
  6. Choose your activity level — be honest; overestimating activity is the most common mistake people make.
  7. Click "Calculate" — review your TDEE, BMR, and weight-change calorie targets.

Mifflin-St Jeor Formula

The Mifflin-St Jeor equation was developed in 1990 and is recommended by the Academy of Nutrition and Dietetics as the preferred method for estimating calorie needs in clinical practice:

Male BMR = (10 × weight_kg) + (6.25 × height_cm) − (5 × age) + 5 Female BMR = (10 × weight_kg) + (6.25 × height_cm) − (5 × age) − 161 TDEE = BMR × Activity Multiplier Activity Multipliers: Sedentary = BMR × 1.200 (desk job, no exercise) Lightly Active = BMR × 1.375 (1–3 workouts/week) Moderately Active = BMR × 1.550 (3–5 workouts/week) Very Active = BMR × 1.725 (6–7 workouts/week) Extra Active = BMR × 1.900 (athlete / physical job) Example (Male, 30 yrs, 5'9" / 175 cm, 160 lbs / 72.6 kg, Moderately Active): BMR = (10 × 72.6) + (6.25 × 175) − (5 × 30) + 5 = 726 + 1093.75 − 150 + 5 = 1,674.75 kcal/day TDEE = 1,674.75 × 1.55 ≈ 2,596 kcal/day

Activity Level Reference Table

Activity LevelMultiplierWho It Fits
Sedentary× 1.200Office job, minimal exercise, mostly sitting
Lightly Active× 1.375Light exercise or sports 1–3 days/week
Moderately Active× 1.550Moderate exercise or sports 3–5 days/week
Very Active× 1.725Hard exercise or sports 6–7 days/week
Extra Active× 1.900Very hard exercise daily + physical work or 2x training

When to Use a Calorie Calculator

Use this calorie calculator whenever you are starting a new diet or fitness program and need a personalized baseline. It is especially valuable for people who have been eating intuitively but not seeing the scale move — knowing your TDEE explains why a "healthy diet" may still maintain or gain weight if calories exceed your TDEE. Tracking calories against your calculated target is the most evidence-based short-term strategy for reliable weight change.

Athletes and gym-goers use calorie calculators to periodize their nutrition, alternating between cutting phases (calorie deficit) and bulking phases (calorie surplus) to manage body composition strategically. If you are new to calorie counting, start at your maintenance level for two weeks while tracking intake to see how accurately the formula predicts your actual maintenance. Then adjust your target accordingly.

Remember that the Mifflin-St Jeor equation, like all BMR formulas, is an estimate. Factors like thyroid function, sleep quality, stress hormones, gut health, and genetic metabolism differences mean your actual TDEE may be somewhat higher or lower than calculated. Treat the result as a starting point, monitor your weight over 2–3 weeks, and adjust your calorie target up or down by 100–200 calories based on real-world results. Always consult a registered dietitian or physician before making drastic changes to your diet, especially if you have a medical condition.

Frequently Asked Questions

How many calories should I eat per day? +
Your daily calorie needs depend on your age, sex, height, weight, and activity level. The result is your TDEE (Total Daily Energy Expenditure). To maintain your current weight, eat at your TDEE. For most moderately active adults, TDEE falls between 1,800 and 2,800 calories per day. Women generally need fewer calories than men due to lower average lean body mass.
What is BMR and how is it different from TDEE? +
BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest — just to keep your heart beating, lungs breathing, and cells functioning. TDEE (Total Daily Energy Expenditure) is your BMR multiplied by an activity factor to account for calories burned through movement and exercise. TDEE is always higher than BMR. Eating at your TDEE maintains weight; eating at your BMR for extended periods would cause weight loss but is generally not recommended without medical supervision.
How do I use calories to lose weight? +
To lose weight, eat fewer calories than your TDEE. A deficit of 500 calories per day results in approximately 1 lb (0.45 kg) of fat loss per week, since one pound of fat contains roughly 3,500 calories. A 250-calorie deficit produces about 0.5 lb/week — slower but often easier to sustain. Combine a modest calorie reduction with strength training to preserve muscle while losing fat, which improves body composition even more than calorie restriction alone.
Is the Mifflin-St Jeor equation the most accurate? +
Yes, among the commonly used BMR equations, the Mifflin-St Jeor equation (1990) has been shown to be the most accurate for predicting resting metabolic rate in most adults, according to a landmark study published in the Journal of the American Dietetic Association. It outperforms older formulas like Harris-Benedict (1919) in study populations. That said, no formula is perfectly accurate for every individual — variations in body composition, hormones, and genetics mean results can differ by up to 15% from lab-measured values.
Is this calorie calculator free? +
Yes — the Calorie Calculator on CLCU Online is completely free. No account creation, no email address, and no payment of any kind is required. Calculate your daily calorie needs as many times as you like, whether you're adjusting for a new activity level or tracking changes over time.

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