Calorie Calculator
Your body burns calories even at rest — this is your Basal Metabolic Rate (BMR). Adding the energy used by daily activity and exercise gives your Total Daily Energy Expenditure (TDEE), a widely used estimate of how many calories you need each day to maintain your current weight. This calculator uses the Mifflin-St Jeor equation, generally considered one of the more accurate BMR formulas for most adults.
How to use the calorie calculator
- Enter your sex, age, height and weight.
- Choose the activity level that best matches your typical week.
- Read your BMR (calories at rest) and TDEE (calories to maintain your current weight), along with rough estimates for mild weight loss or gain.
Formula
BMR (Mifflin-St Jeor): Male = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5. Female = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161.
TDEE = BMR × activity multiplier (1.2 sedentary to 1.9 very active).
Worked examples
A moderately active 30-year-old
Male, 170cm, 68kg, moderate activity: BMR ≈ 1,597.5 kcal, TDEE ≈ 1,597.5 × 1.55 ≈ 2,476 kcal/day to maintain current weight.
Mild weight loss target
A common approach is eating roughly 500 kcal/day below TDEE, which corresponds to losing about 0.5 kg a week — this calculator shows that figure alongside your maintenance calories.
Macronutrient balance, and why formulas differ slightly
Calories tell you how much to eat, but what you eat also matters. A commonly cited general starting point for splitting daily calories across macronutrients is roughly 45–65% from carbohydrates, 20–35% from fat and 10–35% from protein — though the right balance depends on activity level, goals and individual health, and is best set with a doctor or dietitian rather than a fixed rule.
This calculator uses the Mifflin-St Jeor equation, published in 1990 and generally considered more accurate for most modern adults than the older Harris-Benedict equation (1919, revised 1984), which tends to slightly overestimate BMR for a lot of people. Both are population-average formulas — an individual's actual metabolism can still differ by 10% or more due to genetics, muscle mass and other factors, so treat the result as a well-informed starting point to adjust from based on real-world weight change, not an exact number.
Common mistakes to avoid
- Treating TDEE as an exact number — it is a population-average estimate; real metabolism varies by individual and changes as weight changes.
- Picking an activity level that flatters rather than matches actual weekly exercise, which overestimates calorie needs.
- Cutting calories too aggressively — very large deficits are hard to sustain and can affect muscle mass and energy levels; consult a doctor or dietitian before major changes.
Frequently asked questions
What is the difference between BMR and TDEE?
BMR is the energy your body needs at complete rest just to function. TDEE adds the calories burned through daily activity and exercise on top of BMR — it is the more useful number for planning food intake.
How accurate is the Mifflin-St Jeor equation?
It is widely regarded as one of the more accurate BMR prediction formulas for the general adult population, though individual metabolism can vary by 10% or more from any formula-based estimate.
How many calories should I eat to lose weight?
A common, moderate approach is eating around 500 kcal/day below your TDEE for roughly 0.5 kg/week of loss — but rate and safety depend on your starting weight and health, so check with a doctor or dietitian for a plan suited to you.
Is this medical advice?
No. It is an educational estimate based on standard formulas, not a substitute for personalised advice from a doctor, dietitian or nutritionist.
Reviewed September 29, 2026 by the CalcSolver editorial team. Found a mistake? Tell us; see our editorial policy.