How to Use the Calorie Calculator
- Select your biological sex, then enter your age, height, and weight.
- Choose your activity level from the dropdown — be honest for the most accurate result.
- Your BMR and TDEE appear instantly, along with calorie targets for different goals.
BMR vs. TDEE — What's the Difference?
Two numbers are central to understanding your calorie needs:
- BMR (Basal Metabolic Rate) — The number of calories your body burns at complete rest just to maintain vital functions: breathing, circulation, cell production, and temperature regulation.
- TDEE (Total Daily Energy Expenditure) — Your actual daily calorie burn, accounting for all physical activity. This is the number you use to plan your diet.
TDEE = BMR × Activity Factor. For example, someone with a BMR of 1,600 kcal who exercises moderately 3–5 days per week has a TDEE of roughly 1,600 × 1.55 = 2,480 kcal/day.
Calorie Targets by Goal
- Weight loss (mild) — TDEE minus 250 kcal/day ≈ 0.25 kg loss per week.
- Weight loss (moderate) — TDEE minus 500 kcal/day ≈ 0.5 kg loss per week.
- Weight maintenance — Eat at TDEE to keep current weight.
- Muscle gain (lean bulk) — TDEE plus 250–500 kcal/day with adequate protein.
Avoid deficits below 1,200 kcal/day for women or 1,500 kcal/day for men without medical supervision, as very low calorie intake can impair nutrition and metabolism.
The Mifflin-St Jeor Formula
This calculator uses the Mifflin-St Jeor equation, considered the most accurate for estimating BMR in most adults:
- Men:
BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) + 5 - Women:
BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) − 161
Research has shown the Mifflin-St Jeor formula to be more accurate than the older Harris-Benedict equation for predicting resting energy expenditure in both healthy and obese individuals.
Frequently Asked Questions
How accurate is this calculator?
Calorie calculators provide an estimate. Individual metabolic rates vary based on genetics, muscle mass, hormones, and other factors. Use the result as a starting point and adjust based on real-world results over 2–4 weeks.
Which activity level should I choose?
Most people overestimate their activity level. Choose "sedentary" if you have a desk job and don't exercise regularly. "Lightly active" suits 1–3 casual workouts per week. "Moderately active" fits 3–5 dedicated workout sessions. "Very active" applies to daily intense exercise or physical labor.
Should I eat exactly my TDEE?
For weight maintenance, yes. For weight loss, eat 300–500 fewer calories. For muscle gain, eat 250–500 more. Track your weight weekly and adjust by 100–200 kcal if results don't match expectations after 2–3 weeks.
Why is my BMR different from other calculators?
Different calculators use different formulas (Mifflin-St Jeor, Harris-Benedict, Katch-McArdle). Minor differences are expected. The Mifflin-St Jeor formula used here is widely considered the most accurate for the general population.