Estimate your daily calorie needs using the Mifflin–St Jeor Equation. Enter age, gender, height, weight, and activity level to calculate BMR and TDEE.
This Calorie Calculator estimates your daily calorie needs by computing your Basal Metabolic Rate (BMR) using the Mifflin–St Jeor Equation, then multiplying by an activity factor to estimate your Total Daily Energy Expenditure (TDEE). TDEE is the number of calories you need to eat to maintain your current weight at your current activity level. To find your BMR alone, see the BMR Calculator.
BMR (Men) = (10 × weight kg) + (6.25 × height cm) − (5 × age) + 5 BMR (Women) = (10 × weight kg) + (6.25 × height cm) − (5 × age) − 161 TDEE = BMR × Activity Factor
Female, age 28, 5'6" (167.6 cm), 140 lb (63.5 kg), moderately active: BMR = (10 × 63.5) + (6.25 × 167.6) − (5 × 28) − 161 BMR = 635 + 1,047.5 − 140 − 161 = 1,382 cal/day TDEE = 1,382 × 1.55 = 2,142 cal/day
A commonly cited rule is that 1 lb of body fat ≈ 3,500 calories. While the relationship isn't perfectly linear in practice (water weight, metabolic adaptation, and muscle retention all vary), it's a useful planning benchmark. A 250 cal/day deficit produces roughly 0.25 kg (0.5 lb)/week loss; a 500 cal/day deficit produces roughly 0.5 kg (1 lb)/week.
TDEE estimates from any formula are approximations with a margin of error of roughly ±10%. Individual variation in metabolism, gut microbiome, hormonal factors, and NEAT (non-exercise activity thermogenesis — fidgeting, posture, unconscious movement) means two people with identical stats can have meaningfully different calorie needs. The best approach: start with the estimate, then track your actual weight trend for 2–4 weeks and adjust intake by 100–200 calories as needed. For context on your current weight status, pair this tool with the BMI Calculator and the Body Fat Calculator.
This calculator first computes your BMR (calories burned at complete rest) using the Mifflin–St Jeor Equation, then multiplies by your activity factor to get TDEE — your total daily calorie burn including exercise and daily movement. TDEE is the number of calories you need to eat to maintain your current weight.
BMR (Basal Metabolic Rate) is the calories your body burns at complete rest — just to sustain breathing, circulation, and organ function. TDEE (Total Daily Energy Expenditure) includes BMR plus all additional calories burned through activity — walking, exercise, even fidgeting. For most people, TDEE is 20–90% higher than BMR depending on activity level.
To lose weight, consume fewer calories than your TDEE. A 500 calorie/day deficit below TDEE creates roughly a 0.5 kg (1 lb) of fat loss per week. A deficit of 10–20% is sustainable for most people. Deficits larger than 25% risk muscle loss, metabolic slowdown, and nutrient deficiencies. Never go below your BMR without medical supervision.
Eat 5–15% above your TDEE (a 'lean bulk'). A surplus of 200–350 calories/day is enough to support muscle growth while minimizing fat gain. Pair this with resistance training and a high protein intake (1.6–2.2 g/kg body weight). Larger surpluses ('dirty bulking') build muscle faster but add significant fat.
A pound (0.45 kg) of body fat contains roughly 3,500 calories. This means a 500 calorie/day deficit leads to approximately 1 lb/week of fat loss over time. In practice, the relationship isn't perfectly linear — water weight, metabolic adaptation, and composition of weight lost (fat vs. muscle) all vary. Most people see 0.25–0.75 kg (0.5–1.5 lb) loss per week at a moderate deficit.
The Mifflin–St Jeor formula is accurate within ±10% for most people, which means results are reliable estimates, not exact numbers. Individual variation — genetics, gut microbiome, hormones, and NEAT (non-exercise activity thermogenesis) — means two people with identical stats can have meaningfully different calorie needs. Use the result as a starting point, then adjust based on 2–4 weeks of actual weight trends.
Be honest — most people overestimate activity. Sedentary: desk job, minimal movement. Lightly active: 1–3 light workouts or 7,000–10,000 steps/day. Moderately active: 3–5 harder workouts/week. Very active: intense training 6–7 days/week or physically demanding job. Extra active: double training sessions or extremely strenuous manual labor. When in doubt, choose one level lower.
This depends on your approach. If you use TDEE from this calculator, it already accounts for your activity level — so you typically should not eat back extra exercise calories. If you use BMR and log workouts separately (as some apps like MyFitnessPal do by default), you add exercise calories back. Using TDEE is simpler and preferred for most people.