GenzeeCalorie Calculator (BMR & TDEE)
Your daily calorie needs from the Mifflin-St Jeor equation: BMR, maintenance calories, and targets for losing or gaining weight.
Maintenance calories (TDEE)
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BMR and TDEE: the two numbers behind every diet
Your BMR (Basal Metabolic Rate) is the energy your body burns at complete rest — keeping the heart beating, lungs breathing, brain thinking. Your TDEE (Total Daily Energy Expenditure) adds everything else: walking, working, exercise, even digesting food. TDEE is your maintenance number — eat that many calories daily and your weight holds steady. Eat consistently below it and you lose weight; above it, you gain. Every diet that works, works through this equation, whatever it claims on the label.
How to use this calculator
Enter weight, height, age and sex, then pick the activity level that honestly matches your week (most office workers are "sedentary" or "light" — overestimating activity is the most common error). The tool shows your BMR, your maintenance TDEE, and adjusted targets for losing or gaining roughly half a kilogram per week.
The formula
TDEE = BMR × activity factor (1.2 – 1.9)
Mifflin-St Jeor is the equation most dietitians use today — studies find it the most accurate of the common formulas for modern populations. The ±500 kcal adjustments approximate a 0.5 kg weekly change, since a kilogram of body fat stores roughly 7,700 kcal.
Worked example
A 30-year-old man, 70 kg and 175 cm: BMR = 700 + 1,093.75 − 150 + 5 ≈ 1,649 kcal. With light activity (×1.375) his TDEE is about 2,267 kcal. To lose half a kilo a week he'd target ~1,767 kcal; to bulk up, ~2,767 kcal. For scale: a plate of chicken biryani runs 600–800 kcal and a samosa about 250 — which is why "I barely eat" and "I can't lose weight" so often coexist. Tracking, even roughly, beats guessing.
Using the numbers well
Treat the outputs as starting estimates with a real margin of error (±10% is normal). Eat at your target for three or four weeks, watch the trend on the scale, and adjust by 100–200 kcal if nothing moves. Never go below ~1,200 kcal (women) / ~1,500 kcal (men) without medical supervision, and re-run the calculation every 5 kg of change — a lighter body burns less. Pair this tool with the BMI calculator for your healthy weight range, and read our calorie deficit guide for the practical version of all this.
Frequently asked questions
How accurate are calorie calculators?
Within about ±10% for most people — genetics, muscle mass and hormones create real variation. Use the number as a starting point, then adjust based on 3–4 weeks of actual results.
Which activity level should I pick?
Be honest and err low. A desk job with a daily walk is 'light', not 'moderate'. Most people overestimate activity and then wonder why the maintenance number seems too high.
Is eating below BMR dangerous?
Chronically eating far below BMR tends to be unsustainable and can cost muscle and nutrition quality. Standard advice keeps deficits moderate (300–500 kcal below TDEE) and floors intake at 1,200–1,500 kcal without supervision.
Why do men and women get different numbers?
Body composition differs on average — more muscle mass raises resting burn. The Mifflin-St Jeor equation encodes this in its +5 / −161 constant.
Do I need to hit the target exactly every day?
No — the weekly average is what matters. A 300-kcal overshoot on Friday balanced by lighter days changes nothing. Consistency over weeks beats daily perfection.