Calorie calculator

How to calculate your daily calorie needs

1. Select your biological sex. The formula differs slightly for men and women.
2. Enter your age, height (cm), and weight (kg).
3. Choose your activity level from sedentary to very active.
4. Your TDEE and five calorie targets (from weight loss to muscle gain) appear instantly.

Common uses

• Finding your maintenance calories before starting a weight loss diet, then checking progress against a healthy weight range for your height
• Setting a calorie target for a muscle gain (lean bulk) phase alongside tracking body fat percentage
• Understanding how activity level affects your daily energy needs

Technical specification

• Algorithm or formula: Mifflin-St Jeor BMR (1990): men BMR = 10w + 6.25h − 5a + 5, women BMR = 10w + 6.25h − 5a − 161 (w in kg, h in cm, a in years). TDEE = BMR × activity factor (1.2, 1.375, 1.55, 1.725, 1.9).
• Browser API or library: Pure JavaScript arithmetic. No external library.
• Input limits: Numeric, metric only: age 13 to 120 years, height 80 to 250 cm, weight 20 to 400 kg. Convert pounds and inches to kg and cm first.
• Output: TDEE and five rounded calorie targets (mild loss, loss, maintenance, mild gain, gain) corresponding to ±250 and ±500 kcal offsets.
• Known limitations: A predictive equation, not a measurement. Reported mean accuracy is within roughly ±10 percent of indirect calorimetry. Activity multipliers are coarse estimates of NEAT and exercise.

Frequently asked questions

How many calories should I eat per day?

Most adults need between 1,600 and 3,000 calories per day depending on age, sex, height, weight, and activity level. The calculator uses the Mifflin-St Jeor equation to estimate your Total Daily Energy Expenditure (TDEE) and shows five targets from weight loss to muscle gain. Results are estimates for informational purposes only.

What is TDEE?

Total Daily Energy Expenditure (TDEE) is the total number of calories your body burns in a day, accounting for your basal metabolic rate and physical activity level. Eating at your TDEE maintains your current weight.

Do I need an account to use this calculator?

The calculator works without an account. Open the page and enter your details. All calculations run in your browser. Our servers are not involved at any point.

Which calorie formula does this calculator use?

This calculator uses the Mifflin-St Jeor equation (1990), which is the formula most recommended by registered dietitians due to its accuracy across a wide range of body types.