Daily Calorie Calculator (Mifflin-St Jeor)
Estimate your BMR and daily calorie needs (TDEE) from age, sex, weight, height, and activity level using the Mifflin-St Jeor equation, with weight-loss and gain targets. Runs in your browser.
Daily calories
- BMR (resting)
- 1780 kcal/day
- Maintenance (TDEE)
- 2759 kcal/day
- Mild weight loss (−0.25 kg/wk)
- 2484 kcal/day
- Weight loss (−0.5 kg/wk)
- 2209 kcal/day
- Weight gain (+0.5 kg/wk)
- 3309 kcal/day
BMR uses the Mifflin-St Jeor equation (1990), the most accurate common predictive formula. Weight-change targets assume ~7,700 kcal per kg of body mass. Estimates only — individual needs vary. Not medical advice.
About this tool
Your daily calorie need is your basal metabolic rate (BMR) — the energy your body uses at complete rest — scaled up by how active you are. This calculator estimates BMR with the Mifflin-St Jeor equation, which research has found to be the most accurate of the common predictive formulas for the general population, more reliable than the older Harris-Benedict equation. It then multiplies BMR by a standard activity factor (1.2 sedentary up to 1.9 extra active) to give your total daily energy expenditure (TDEE) — roughly the calories to maintain your current weight — and derives targets for losing or gaining weight using the convention that about 7,700 kcal equals one kilogram of body mass. These are population estimates: real metabolism varies with genetics, body composition, and adaptation, so use the maintenance figure as a starting point and adjust based on how your weight actually responds over two to three weeks. It is informational, not medical or dietary advice. Everything runs in your browser.
How to use it
- Enter sex, age, weight, and height (metric or imperial).
- Choose the activity level that matches your typical week.
- Read your BMR and maintenance calories (TDEE).
- Pick a loss or gain target, then adjust after tracking your real-world results.
Frequently asked questions
- What is the Mifflin-St Jeor equation?
- A 1990 formula for resting metabolic rate: 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5 for men (− 161 for women). It is widely regarded as the most accurate simple predictive equation for healthy adults and is what this tool uses.
- What is the difference between BMR and TDEE?
- BMR is the energy you burn at rest just to stay alive. TDEE (total daily energy expenditure) is BMR multiplied by an activity factor to include movement and exercise — it is the number that approximates your maintenance calories.
- How do I pick an activity multiplier?
- Be honest and slightly conservative: sedentary (1.2) for desk work and no exercise, lightly active (1.375) for 1–3 light sessions, moderately active (1.55) for 3–5, very active (1.725) for 6–7 hard sessions, extra active (1.9) for physical jobs or two-a-days. Most people overestimate.
- How are the weight-loss and gain targets derived?
- From the maintenance figure, using the approximation that ~7,700 kcal equals one kilogram of body mass. A 550 kcal/day deficit projects to roughly 0.5 kg per week. These are projections, not guarantees — your body adapts.
- Why is my real weight change different from the estimate?
- Predictive equations have individual error, and metabolism adapts to dieting (adaptive thermogenesis), water weight fluctuates, and activity is hard to estimate. Use the number as a starting point and adjust based on 2–3 weeks of actual data.
- Is this medical or dietary advice?
- No. It is an informational estimate. For a tailored nutrition plan or any medical condition, consult a registered dietitian or physician.