Calorie Calculator
Estimate daily calorie needs with the Mifflin-St Jeor formula.
Understanding your daily calorie needs is the starting point for any nutrition plan, whether your goal is weight loss, muscle gain, or maintenance. This calculator uses the Mifflin-St Jeor equation — widely considered the most accurate formula — with your age, gender, height, weight, and activity level.
Your result will appear here...
How to Calculate Your Daily Calories
- Enter your age — your metabolic rate decreases roughly 1–2% per decade after age 20, so age is a key factor.
- Enter your weight in kilograms — more body mass requires more energy at rest. Convert from pounds by dividing by 2.205.
- Enter your height in centimetres — taller individuals generally have a higher BMR. Convert from feet/inches if needed.
- Set the gender adjustment — enter
5for male or-161for female. This accounts for differences in average body composition. - Click Calculate — the tool outputs your BMR (calories burned at rest) and estimated maintenance calories assuming moderate activity (×1.55).
Frequently Asked Questions
What is the Mifflin-St Jeor equation? ▼
The Mifflin-St Jeor equation is considered the most accurate formula for estimating Basal Metabolic Rate (BMR). It was developed in 1990 and calculates BMR as: 10 × weight(kg) + 6.25 × height(cm) − 5 × age(years) + gender adjustment (+5 for males, −161 for females).
What is the difference between BMR and TDEE? ▼
BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest — just to keep organs functioning. TDEE (Total Daily Energy Expenditure) multiplies BMR by an activity factor (1.2 for sedentary up to 1.9 for very active) to estimate the total calories you actually burn each day.
How accurate is this calorie calculator? ▼
The Mifflin-St Jeor equation is accurate to within about 10% for most healthy adults. Individual variation depends on muscle mass, genetics, hormones, and other factors. Use the result as a starting estimate and adjust based on real-world results over 2–4 weeks.
How many calories should I eat to lose weight? ▼
A safe caloric deficit is 300–500 kcal below your maintenance level, which typically produces 0.25–0.5 kg of fat loss per week. Extreme deficits below 1,200 kcal/day are not recommended without medical supervision as they can cause muscle loss and nutrient deficiencies.
Does exercise change how many calories I need? ▼
Yes. Physical activity significantly increases TDEE. Light exercise adds roughly 20%, moderate exercise 40–55%, and intense daily training up to 90% on top of your BMR. Adjust the multiplier or use a dedicated TDEE calculator for precision.
Is my data stored or uploaded anywhere? ▼
No. This calorie calculator runs entirely in your browser using JavaScript. Your age, weight, height, and results are never sent to any server or stored anywhere.