Calorie Calculator — Daily Calorie Needs
Estimate your BMR and daily calorie needs (TDEE) based on your stats and activity level.
How to use the Calorie Calculator
- Choose Metric or Imperial, then select male or female.
- Enter your age, height, and weight.
- Pick the activity level that honestly matches a typical week.
- Read your BMR, your maintenance calories (TDEE), and the mild weight-loss and weight-gain targets.
About the Calorie Calculator
This calculator estimates two numbers: your BMR (Basal Metabolic Rate) — the calories your body burns at complete rest just to keep organs functioning — and your TDEE (Total Daily Energy Expenditure), which adds in your activity level to estimate the calories you burn in a typical day. It uses the Mifflin-St Jeor equation, which is generally considered more accurate than older formulas like Harris-Benedict for most adults.
TDEE is a useful baseline for weight goals: eating around your TDEE tends to maintain weight, eating consistently below it tends to produce weight loss, and eating above it tends to produce weight gain. This calculator shows your maintenance calories along with common targets for mild weight loss and weight gain.
Worked example
Example: a 30-year-old man, 180 cm tall, weighing 80 kg, with a moderately active lifestyle has a BMR of roughly 1,780 calories and a TDEE of about 2,760 calories per day at maintenance.
The formula and activity multipliers
The Mifflin-St Jeor equation estimates BMR from weight, height, and age: 10 × weight (kg) + 6.25 × height (cm) − 5 × age, plus 5 for men or minus 161 for women. A 35-year-old woman who is 165 cm tall and weighs 65 kg has a BMR of 10 × 65 + 6.25 × 165 − 5 × 35 − 161 ≈ 1,345 calories.
TDEE is BMR multiplied by an activity factor: 1.2 for sedentary, 1.375 for light exercise (1–3 days a week), 1.55 for moderate (3–5 days), 1.725 for active (6–7 days), and 1.9 for very active (hard exercise plus a physical job). With light activity, the woman above has a TDEE of about 1,850 calories. The weight-loss and weight-gain figures are simply TDEE minus or plus 500.
Choosing the right activity level
Most people overestimate their activity. The multiplier covers your whole day, not just workouts, so an office worker who trains three times a week usually belongs in 'light' or 'moderate', not 'active'. If you're unsure between two levels, pick the lower one and adjust after watching your weight for a few weeks.
Using the number well
- Treat it as a starting estimate. Track your weight for 2–3 weeks at a steady intake, then adjust by 100–200 calories based on what actually happens.
- Use weekly averages. Daily weight jumps by a kilogram or more with water and food in your system, which says nothing about fat.
- Recalculate as you change. A lower body weight means a lower BMR and TDEE, which is one reason weight loss slows over time.
- Don't go too low. Very low intakes are hard to sustain and make it hard to get enough protein and nutrients; get medical advice for large or rapid changes.
Frequently asked questions
- What is BMR and how is it different from TDEE?
- BMR is the calories your body needs at complete rest, with no activity at all. TDEE takes BMR and multiplies it by an activity factor to estimate total calories burned in a full day including exercise, walking, and daily movement — it's always higher than BMR.
- How accurate is the Mifflin-St Jeor equation?
- It's one of the most accurate predictive equations validated in research for the general population, but any formula is an estimate — actual metabolism varies by individual factors like muscle mass, genetics, and health conditions. Use it as a starting point and adjust based on real-world results over a few weeks.
- How many calories should I eat to lose weight?
- A commonly cited approach is a deficit of about 500 calories per day below TDEE for roughly 0.5 kg (about 1 lb) of weight loss per week, though this calculator's estimate should be adjusted for your own results — and significant or rapid weight loss should involve a doctor or registered dietitian.
- Why does activity level change the result so much?
- Activity level is multiplied against BMR, so small differences in the multiplier compound across a whole day. Someone who's sedentary versus very active can have a TDEE difference of 800–1000+ calories even with identical BMR, since movement and exercise burn calories on top of baseline metabolism.