Calculate your Basal Metabolic Rate and Total Daily Energy Expenditure based on your stats and activity level.
Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest, just to keep your heart beating, lungs breathing, and organs functioning. It accounts for 60–75% of total daily energy expenditure for most sedentary people.
Total Daily Energy Expenditure (TDEE) multiplies your BMR by an activity factor. Sedentary (desk job, no exercise): ×1.2. Lightly active (1–3 days/week): ×1.375. Moderately active (3–5 days): ×1.55. Very active (hard exercise 6–7 days): ×1.725. Extremely active (athlete/manual labour): ×1.9.
A deficit of roughly 500 kcal/day leads to around 0.45 kg (1 lb) of fat loss per week. Larger deficits lose weight faster but risk muscle loss and metabolic adaptation. Most guidelines recommend not going below 1,200 kcal/day for women or 1,500 for men.
This tool uses the revised Harris-Benedict equation (1984). Men: BMR = 88.362 + (13.397 × weight kg) + (4.799 × height cm) − (5.677 × age). Women: BMR = 447.593 + (9.247 × weight kg) + (3.098 × height cm) − (4.330 × age). The Mifflin-St Jeor equation (1990) is slightly more accurate but both are widely used.
When in a calorie deficit, eating adequate protein (1.6–2.2g per kg of body weight) helps preserve muscle mass. Combined with resistance training, this ensures more fat (rather than muscle) is lost during a cut.
Food labels have a ±20% margin of error, cooking changes calorie content, and different people absorb calories differently. Activity trackers overestimate burn by 20–40% on average. Treat calorie numbers as estimates and adjust based on real-world results over 2–4 weeks.
Calculate your Basal Metabolic Rate (BMR) — the calories your body burns at rest — and your Total Daily Energy Expenditure (TDEE) based on your activity level.
30-year-old male, 175 cm, 75 kg, lightly active
BMR: approx 1,800 kcal/day | TDEE: approx 2,475 kcal/day
25-year-old female, 163 cm, 58 kg, moderately active
BMR: approx 1,390 kcal/day | TDEE: approx 2,155 kcal/day
Mifflin-St Jeor BMR (male): 30 years old, 175 cm, 75 kg
BMR: 1,698.75 kcal/day
TDEE from BMR using activity multipliers
Example: BMR 1,699 × 1.375 = 2,336 kcal/day
The Mifflin-St Jeor equation, published in 1990, is considered the most accurate BMR formula for most people. A 'calorie' in nutrition is actually a kilocalorie (kcal) — 1,000 times the scientific calorie unit. The original Harris-Benedict equation was published in 1919 and is still widely used, though it tends to overestimate calorie needs slightly.
Basal Metabolic Rate is an estimate of the energy your body uses at rest to support essential functions such as breathing and circulation. It is not a recommended calorie target and it does not include normal movement, exercise, digestion, or work. The estimate is useful as a starting point, not a measurement of your metabolism.
The calculator combines your BMR with an activity multiplier to estimate Total Daily Energy Expenditure. Choose the activity level that best represents your usual week, not your most active day. Exercise calories and daily movement vary, so compare the estimate with changes in your weight, energy, hunger, and performance over several weeks.
Use it as general planning information rather than medical advice. Calorie needs change with age, health, body composition, pregnancy, medication, and training load. Avoid extreme restriction, and speak with a qualified clinician or dietitian if you have a medical condition, a history of disordered eating, or a goal that needs supervised nutrition support.
Treat the result as a starting estimate and compare it with your weight trend, energy, hunger, and training over several weeks. Small changes are more informative than reacting to one day of food or one scale reading. Recalculate after a substantial change in body weight, activity, or health rather than making large unexplained adjustments.