Calorie Calculator (BMR & TDEE)

This calculator estimates your daily calorie needs - how many calories your body uses at rest (BMR), and how many you burn in total each day including activity (TDEE).

How to Use

Select your gender, age, height, weight, and activity level, then press "Calculate." You'll get your BMR, TDEE, and suggested daily calorie targets for weight loss or gain.

What Is BMR?

BMR (Basal Metabolic Rate) is the minimum number of calories your body needs to stay alive - for functions like breathing, heartbeat, and other basic body processes - even if you spent the entire day resting in bed.

What Is TDEE?

TDEE (Total Daily Energy Expenditure) is your BMR plus the calories burned through daily activity (walking, exercise, work). It's the actual number that tells you how many calories you need each day to maintain your current weight.

Understanding Your Result

• To maintain your weight, eat around your TDEE
• To lose weight, eat fewer calories than your TDEE (a deficit)
• To gain weight, eat more calories than your TDEE (a surplus)

Limitations

This result is an estimate, not an exact figure. Actual calorie needs can vary due to muscle mass, hormones, medical conditions, and genetics. Always consult a doctor or dietitian before starting a weight-loss or weight-gain plan.

FAQs

Is this calculator accurate for everyone?
It provides a reliable estimate for the general population, though results may vary slightly for people who are very muscular or have a very high body fat percentage.

Should I eat the exact same calories every day?
No, your weekly average matters more than the exact number each day. Small day-to-day variation is normal.

How much of a deficit is safe for weight loss?
A deficit of about 500 kcal from your TDEE (roughly 0.5 kg/week loss) is generally considered safe. Larger deficits (1000+ kcal) should only be done under medical supervision.

Formula Used

The Mifflin-St Jeor equation is used for BMR calculation (current gold-standard, published 1990):

• Men: BMR = (10 x weight kg) + (6.25 x height cm) - (5 x age) + 5
• Women: BMR = (10 x weight kg) + (6.25 x height cm) - (5 x age) - 161

Alternate Formula (reference): Harris-Benedict Equation (Revised 1984)

• Men: BMR = 88.362 + (13.397 x weight kg) + (4.799 x height cm) - (5.677 x age)
• Women: BMR = 447.593 + (9.247 x weight kg) + (3.098 x height cm) - (4.330 x age)

Mifflin-St Jeor is considered more accurate in modern clinical/nutrition guidelines, particularly in overweight/obese populations, which is why it is the default formula in this calculator.

TDEE Calculation

TDEE = BMR x Activity Multiplier

Clinical Notes

• These equations are validated for healthy adults; in critically ill, pregnant, or extreme body-composition patients, indirect calorimetry is more reliable
• Results may be less accurate in amputees or patients with unusual body composition
• Weight-management interventions should be individualized under dietitian/clinician supervision

Evidence & References

1. Mifflin MD, St Jeor ST, et al. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. 1990;51(2):241-247.
2. Roza AM, Shizgal HM. The Harris Benedict equation reevaluated. Am J Clin Nutr. 1984;40(1):168-182.