How it works
Enter four things — sex, age, height, and weight — and pick the activity level that best matches a normal week. The calculator instantly shows your TDEE (Total Daily Energy Expenditure): the total calories your body burns per day, including your resting metabolism plus all movement and exercise. It also shows your BMR (Basal Metabolic Rate — what you'd burn at complete rest) and ready-made calorie targets for cutting (−500 calories) and bulking (+300 calories). Use the toggle at the top to switch between US units (ft/in, lb) and metric (cm, kg) — your numbers are converted automatically.
The formula — Mifflin-St Jeor
This calculator uses the Mifflin-St Jeor equation (Mifflin MD, St Jeor ST, et al., "A new predictive equation for resting energy expenditure in healthy individuals," American Journal of Clinical Nutrition, 1990). Validation studies have found it the most accurate of the common predictive equations for healthy adults, and the Academy of Nutrition and Dietetics recommends it over the older Harris-Benedict equation (1919), which tends to overestimate modern resting metabolism by around 5%.
- Men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
- Women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
US-unit inputs are converted exactly (1 in = 2.54 cm, 1 lb = 0.45359237 kg) before the formula is applied. TDEE is then BMR multiplied by a standard activity factor — sedentary ×1.2, lightly active ×1.375, moderately active ×1.55, very active ×1.725, extra active ×1.9 — the multiplier scale established in Harris-Benedict-lineage research and used by most TDEE calculators.
Example
A 30-year-old man, 5′9″ (175.3 cm) and 154 lb (69.9 kg): BMR = 10 × 69.9 + 6.25 × 175.3 − 5 × 30 + 5 ≈ 1,649 calories. If he trains 3–5 days a week (moderately active, ×1.55), his TDEE is about 2,556 calories a day. To cut, he'd start around 2,056 calories a day — a 500-calorie daily deficit, which is roughly 3,500 calories a week, or about 1 lb of fat. To bulk, he'd start around 2,856 calories a day for lean gains.
Frequently asked questions
What is TDEE?
TDEE (Total Daily Energy Expenditure) is the total number of calories your body burns in a day: your basal metabolic rate plus everything you do — walking, working, workouts, even digesting food. Eat about your TDEE to maintain your weight, less to lose, more to gain.
What's the difference between TDEE and BMR?
BMR is the energy your body would burn doing nothing at all — just breathing, circulating blood, and keeping organs running. It's usually 60–70% of your daily burn. TDEE = BMR × activity factor, so it's the number that actually matters for setting your daily calories.
How is TDEE calculated?
This calculator first estimates your BMR with the Mifflin-St Jeor equation (10 × weight in kg + 6.25 × height in cm − 5 × age + 5 for men, −161 for women), then multiplies it by an activity factor from 1.2 (sedentary) to 1.9 (extra active).
How many calories should I eat to lose weight?
A common, sustainable starting point is TDEE − 500 calories a day, which works out to roughly 1 lb (about 0.45 kg) of fat per week. If the cutting target drops below roughly 1,200 calories, shrink the deficit or talk to a professional first — very-low-calorie diets shouldn't be attempted without medical supervision. Adjust based on how your weight actually changes over 2–4 weeks.
How accurate is a TDEE calculator?
It's a statistical estimate, not a measurement. Even the Mifflin-St Jeor equation — the formula validation studies found most accurate for healthy adults — can be off by ±10% or more for an individual, depending on muscle mass, body fat percentage, hormones, and how much you move outside the gym. It was developed for healthy adults and is not intended for children, pregnancy, or medical conditions. Use your result as a baseline, track your weight for 2–4 weeks, and adjust in 100–200-calorie steps.