Calorie Calculator
Estimate your daily calorie needs based on age, weight, height and physical activity level.
This is an estimate based on population formulas and doesn't replace an individualized assessment. Consult a dietitian or doctor before setting calorie targets.
The calorie calculator estimates total daily energy expenditure (also called TDEE) from your basal metabolic rate — the energy your body uses at rest — multiplied by a physical activity factor. The result represents roughly how many calories are needed to maintain your current weight, given the routine you entered.
How to use
- Enter your biological sex, age, weight and height.
- Choose the activity level that best matches your routine.
- Watch the estimated daily calorie needs update automatically.
Worked example
Consider a 30-year-old woman, 65 kg, 165 cm, moderately active. The Mifflin-St Jeor formula estimates a basal metabolic rate of about 1,373 kcal per day. Multiplying by the moderate activity factor (1.55) gives an estimated daily expenditure of around 2,128 kcal — roughly what she'd need to eat to maintain her current weight on that routine.
Frequently asked questions
How is calorie expenditure calculated?
The calculator uses the Mifflin-St Jeor formula to estimate basal metabolic rate (BMR) from weight, height, age and biological sex, then multiplies that value by a factor based on the activity level you entered.
Does this result help with losing or gaining weight?
The number shown is a maintenance estimate for your current weight. Adjustments for weight loss or gain involve other individual variables and should be guided by a dietitian or doctor.
Why does the calculator ask for biological sex?
The Mifflin-St Jeor formula uses a different constant for each biological sex, because average body composition (lean mass proportion) affects basal metabolic rate.
What's the difference between BMR and TDEE?
BMR (basal metabolic rate) is the energy your body uses just to stay alive at rest. TDEE (total daily energy expenditure) is BMR multiplied by your activity factor, so it also includes what you burn moving through the day. TDEE is what this calculator shows.
Why is my result different from other calculators?
There are several formulas (Mifflin-St Jeor, Harris-Benedict, Katch-McArdle), each using different constants, and activity factors vary between sites. Small differences are normal — these are all population estimates, not exact measurements.
How do I use this number to lose or gain weight?
Generally, eating fewer calories than your TDEE tends to cause weight loss, and eating more tends to cause gain. But the ideal size of that deficit or surplus, how you split nutrients, and doing it safely all depend on individual factors — which is why guidance from a dietitian is recommended.