The two numbers that matter
BMR — basal metabolic rate — is the energy your body burns doing nothing but existing: breathing, circulating blood, maintaining temperature. TDEE — total daily energy expenditure — is BMR multiplied by an activity factor, and it's your real daily maintenance number: eat that many calories and your weight holds steady. This calculator computes both using the Mifflin-St Jeor equation, the formula nutrition research has found most accurate for most adults.
How to use it
- Enter sex, age, height and weight (metric or imperial).
- Choose your activity level honestly — most desk workers who gym twice a week are "lightly active," not "moderately." Overestimating activity is the #1 reason calculated targets don't match results.
- Read your maintenance number, then the goal table: roughly −500 calories a day produces about 0.5 kg of loss per week; +500 the reverse.
Using the numbers well
- Treat the output as a starting estimate, not a verdict. Individual metabolisms vary around any formula. Eat at the calculated target for two or three weeks, watch the trend, and adjust by 100–200 calories.
- Slower is more sustainable. The 0.25 kg/week targets are easier to live with and preserve more muscle than aggressive cuts.
- Very low intakes are flagged for a reason — below roughly 1,200–1,500 calories, meeting nutrient needs is hard without professional supervision.
- Recalculate after every ~5 kg change; a lighter body burns fewer calories.
This tool provides general information using population formulas — it isn't medical or dietary advice. For medical conditions, pregnancy, eating-disorder history or large weight changes, please work with a doctor or registered dietitian.
Frequently asked questions
Which formula does this calculator use?
Mifflin-St Jeor — the equation research bodies including the Academy of Nutrition and Dietetics recommend as the most accurate for most adults. For men: 10×kg + 6.25×cm − 5×age + 5; for women the same minus 161 at the end.
What's the difference between BMR and TDEE?
BMR is what you'd burn lying still all day — your body's idle consumption. TDEE multiplies BMR by an activity factor to estimate what you actually burn, and it's the number to eat at for weight maintenance.
Why am I not losing weight at the calculated deficit?
Usually one of three things: activity level was overestimated (most people's is 'light', not 'moderate'), intake is underestimated (oils, drinks and bites count), or the formula simply runs a bit high for your body. Track honestly for two weeks, then adjust by 100–200 calories.
Is this medical advice?
No — it's a population formula for general information. For medical conditions, pregnancy, adolescence or major weight changes, work with a doctor or registered dietitian.