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BMI Calculator
Calculate your Body Mass Index instantly.
Calorie Calculator
Calculate your daily calorie needs based on your age, sex, height, weight, and activity level. Get separate targets for weight loss, maintenance, and muscle gain using the Mifflin-St Jeor equation.
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How to use the Calorie Calculator
Choose metric or imperial
Select your preferred unit system. Metric uses kg and cm; imperial uses lbs, feet, and inches.
Enter your stats
Provide your sex, age, height, and weight. These feed the Mifflin-St Jeor equation to calculate your Basal Metabolic Rate (BMR).
Select your activity level
Be honest here — most people are more sedentary than they think. If you sit at a desk most of the day with occasional gym sessions, choose Lightly Active.
Pick your goal
Your Total Daily Energy Expenditure (TDEE) is adjusted up or down based on your goal. A deficit of 500 kcal/day produces roughly 1 lb/week of fat loss.
About this Calorie Calculator
Calories are the fundamental currency of body weight. When you consume more than you burn, you gain weight; when you burn more than you consume, you lose it. The challenge is knowing how many calories you actually burn — and that's where a calorie calculator helps. Your Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest just to maintain basic functions: breathing, circulation, cell repair. For most people, BMR accounts for 60–75% of total calorie expenditure. The Mifflin-St Jeor equation (1990) is the most validated formula for estimating BMR and is recommended by the Academy of Nutrition and Dietetics. Your Total Daily Energy Expenditure (TDEE) multiplies BMR by an activity factor — from sedentary (×1.2) to extremely active (×1.9). This is where most calorie-counting goes wrong: people overestimate how active they are. A 45-minute gym session doesn't automatically qualify as 'very active' if the rest of your day is desk-bound. For weight loss, a deficit of 500 kcal/day is a commonly cited guideline for ~0.5 kg/week of fat loss. More aggressive deficits risk muscle loss and are harder to sustain. For weight gain, a modest surplus of 250–500 kcal/day minimises fat gain while supporting muscle building. The macro targets shown are approximate starting points. Individual needs vary significantly based on training type, health conditions, and dietary preferences. This tool provides estimates — not clinical prescriptions.
Frequently Asked Questions
Your daily calorie needs depend on your age, sex, height, weight, and activity level. Most sedentary adults need 1,600–2,400 calories per day for maintenance. Active individuals need more. Our calculator uses the Mifflin-St Jeor equation, currently the most accurate formula for estimating daily calorie needs.
BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest — just to keep your heart beating, lungs breathing, and organs functioning. It accounts for about 60–75% of total calorie expenditure. To find how many calories you need in daily life, your BMR is multiplied by an activity factor to get your TDEE.
A calorie deficit of 500 calories per day typically produces around 0.5kg (1 lb) of fat loss per week. Our calculator shows a 'mild loss' target (−250 cal/day) and a 'moderate loss' target (−500 cal/day). Avoid going below 1,200 calories (women) or 1,500 calories (men) without medical supervision.
The Mifflin-St Jeor equation is a formula for estimating BMR. For men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5. For women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161. Research shows it's more accurate than the older Harris-Benedict equation for most people.
Calorie calculators provide estimates with a margin of error of ±10–15%. Individual metabolic rates vary due to genetics, hormones, muscle mass, and other factors. Use the result as a starting point, track your actual results for 2–3 weeks, and adjust your intake by 100–200 calories if needed.
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