What TDEE actually means
Total daily energy expenditure (TDEE) is the total calories your body burns in a 24-hour period. It has four components: basal metabolic rate (BMR), the thermic effect of food, the calories burned during deliberate exercise, and non-exercise activity thermogenesis (NEAT) — fidgeting, pacing, standing, taking the stairs. BMR is roughly 60–70% of TDEE for most people, and it's the only component this calculator predicts directly. Everything else is accounted for through the activity multiplier.
The formula this calculator uses
We use the Mifflin-St Jeor equation, which was published in 1990 and has been the clinical gold standard ever since. It consistently outperforms older formulas (Harris-Benedict, Katch-McArdle for most people) in validation studies. The equation is:
- Men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
- Women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
TDEE = BMR × activity multiplier. The multipliers range from 1.2 (truly sedentary) to 1.9 (two-a-day training or hard manual labor). Most office workers who exercise 3–5 times a week land at 1.55.
How to pick the right activity multiplier
This is the most-often-mis-set input. People underestimate sedentary and overestimate active. Some honest anchors:
- Sedentary (1.2): desk job, no intentional exercise, maybe 3,000 steps a day. Retired and homebound fits here too.
- Light (1.375): desk job plus 1–3 real workouts a week (not walks).
- Moderate (1.55): desk job plus 3–5 workouts, or an on-your-feet job with minimal gym time.
- High (1.725): 6–7 intense workouts or an active job (nursing, warehouse) plus 3+ workouts.
- Athlete (1.9): two-a-day training, manual labor plus evening sport, or competitive endurance prep.
Cutting, maintaining, bulking
Once you have TDEE, subtract or add calories to drive a specific outcome:
- Sustainable cut: TDEE − 500 kcal/day for roughly 1 lb (0.45 kg) of fat loss per week.
- Slow cut: TDEE − 250 kcal/day. Slower progress but easier adherence and better muscle retention.
- Aggressive cut: TDEE − 750 kcal/day. Reserve for short windows; risk of muscle loss and adherence failure rises fast below this.
- Maintain: eat at TDEE. Use this phase between cuts and bulks, or indefinitely if your body composition is already where you want it.
- Lean bulk: TDEE + 200–300 kcal/day. Produces about 0.25–0.5 lb of weight gain per week, most of which can be muscle if training is adequate.
The 3,500-calorie-per-pound rule (and why it lies)
You'll see this rule everywhere: a pound of fat is 3,500 calories, so a 500 kcal daily deficit burns a pound a week. The math is clean but the biology is messier. Your TDEE drops as you lose weight (you're moving a smaller body). NEAT also drops — when calories go down, people subconsciously fidget less, walk less, take fewer stairs. Both effects mean a 500 kcal deficit in week 1 is not a 500 kcal deficit in week 12.
The practical consequence: track weight trend over 2–4 weeks, and if it stalls, drop another 100–200 kcal, add steps, or both. Don't trust a single TDEE estimate to stay accurate forever.
Pair TDEE with the right macros and protein
TDEE sets the calories. What fills those calories determines whether you retain muscle, feel satiated, and can stick with the plan. Head to the macro calculator to split your TDEE into protein, carbs, and fat for your goal, and to the protein intake calculator to verify your protein floor. If you're using cardio to create part of your deficit, the walking calories calculatorshows how much you're actually earning per mile.
Common TDEE mistakes
Over-reporting exercise
Cardio machines lie. Fitness trackers make generous guesses. Double-check by comparing your TDEE prediction to real weight change over two weeks — if you're eating at predicted maintenance and steadily losing, your real TDEE is lower (or your intake tracking is more generous than you think).
Setting calories by BMR instead of TDEE
A classic crash-diet mistake. Your body does not need exactly BMR calories; BMR is what you'd burn lying in bed for 24 hours. Eating at BMR when your real TDEE is 2,400 is a 700+ kcal deficit — way too aggressive, and almost guaranteed to produce muscle loss and binge episodes.
Ignoring the relationship between sleep and appetite
Sleep deprivation raises ghrelin (hunger) and lowers leptin (satiety). Sleeping under 7 hours makes a given calorie target feel 200–400 kcal harder to hit. The sleep calculator is a surprisingly important sidecar to any TDEE-based plan.
FAQ
Is Mifflin-St Jeor accurate for me?
For most adults of average body composition, it's within ~10% of measured metabolic rate. For very lean, very muscular, or very obese individuals, the Katch-McArdle formula (based on lean body mass) can be more accurate. This calculator uses Mifflin-St Jeor because it doesn't require you to know your body fat percentage.
Why did my TDEE drop after losing 20 lb?
Smaller body, lower BMR. Add ~22 kcal/day per kg of body weight lost. A 9 kg (20 lb) loss typically lowers TDEE by ~200 kcal.
Should I eat more on workout days?
Optional. Calorie cycling (higher on training days, lower on rest days) works fine, but so does eating the same every day. Pick whichever you'll stick with.
How often should I recalculate?
After every 5–8 lb of weight change. You'll also want to recalculate if you meaningfully change your training volume or activity level.