BMR vs TDEE: How Many Calories Should You Eat?
⏱ 2 min readBMR and TDEE are the two numbers behind every calorie target. BMR is what your body burns at complete rest; TDEE is what you burn in a whole day once movement is added. Get these right and a weight goal becomes simple arithmetic — eat below TDEE to lose, above it to gain, around it to maintain.
What BMR is
Your basal metabolic rate (BMR) is the energy your body uses just to keep you alive at rest — breathing, circulation, organ function, maintaining temperature. It's the single biggest part of what you burn, typically 60–70% of daily calories.
The most accurate everyday estimate is the Mifflin-St Jeor equation, which uses your weight, height, age and sex. It's the formula our BMR calculator uses, and research finds it closer to measured values than the older Harris-Benedict equation for most people.
What TDEE is
Total daily energy expenditure (TDEE) is BMR plus everything else you do: walking, workouts, fidgeting and even digesting food. It's estimated by multiplying BMR by an activity factor.
- Sedentary (little exercise): BMR × 1.2
- Light (1–3 days/week): BMR × 1.375
- Moderate (3–5 days/week): BMR × 1.55
- Active (6–7 days/week): BMR × 1.725
- Very active (hard daily training or physical job): BMR × 1.9
Turning TDEE into a weight goal
Roughly 7,700 calories equals one kilogram of body fat (about 3,500 per pound). So a daily deficit of ~500 calories below TDEE trends toward losing about 0.5 kg (1 lb) a week; the same surplus trends toward gaining.
Eat at TDEE to maintain. For fat loss, a 10–20% deficit is sustainable for most people; for lean gains, a 5–15% surplus limits fat gain. Re-estimate your TDEE as your weight changes, since a lighter body burns less.
Where the estimate goes wrong
TDEE formulas are starting points, not lab measurements. The most common errors are over-rating your activity level, then 'eating back' exercise calories on top — double-counting movement the multiplier already included.
Use the number for two to three weeks, track your weight trend, and adjust by 100–200 calories based on what actually happens. Real-world results beat any formula.
Frequently asked questions
Should I eat below my BMR to lose weight faster?
Generally no. Eating below BMR for long periods is hard to sustain and can cost you muscle and energy. A moderate deficit from TDEE (10–20%) is more sustainable. For very low-calorie plans, get professional guidance.
How accurate is a TDEE calculator?
It's a solid estimate, usually within a few hundred calories. Bodies vary, so treat it as a starting point: track your weight for 2–3 weeks and fine-tune your intake from the trend.
Does TDEE change over time?
Yes. As you lose or gain weight your BMR shifts, and activity changes too. Recalculate every few kilograms and whenever your routine changes.