Overview
TDEE — Total Daily Energy Expenditure — is the single most useful number in nutrition planning. It tells you exactly how many calories your body burns across an entire day, accounting for everything from sleep to formal exercise to walking to your desk. Every meaningful calorie target (for weight loss, muscle gain, or maintenance) is derived from TDEE.
The challenge is that TDEE cannot be measured directly without laboratory equipment. Instead, it is estimated using a two-step calculation: first computing your Basal Metabolic Rate (BMR) with a validated formula, then multiplying by an activity factor that represents your lifestyle. This guide walks through that calculation precisely, with the formulas, the activity multiplier table, a worked numerical example, and the most common mistakes that cause inaccurate results.
Use the TDEE Calculator to run this calculation automatically, or follow the steps below to understand the method and build confidence in the number you are using.
What You Need
- Your current weight in kilograms
- Your height in centimetres
- Your age in years
- An honest assessment of your typical weekly activity level
Step 1: Understand the Difference Between BMR and TDEE
BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest — doing nothing except keeping your heart beating, lungs breathing, and cells repairing. If you stayed in bed, perfectly still, for 24 hours, you would burn approximately your BMR in calories.
TDEE takes BMR and scales it up based on how active you actually are. All movement — walking to the kitchen, commuting, exercising, household tasks, fidgeting — burns calories on top of your BMR. TDEE captures all of it.
The practical consequence: BMR alone is never the right number for a calorie target. A sedentary person eats 20% above BMR just to maintain their weight. An active person eats 60–90% above BMR.
The BMR Calculator isolates the BMR step if you want to check that number separately before proceeding.
Step 2: Calculate BMR with Mifflin-St Jeor
The Mifflin-St Jeor equation is the most accurate BMR formula for the general population, validated across multiple large studies and preferred over the older Harris-Benedict equation (which overestimates BMR by 5–15% in most adults).
Men:
BMR = (10 × weight_kg) + (6.25 × height_cm) − (5 × age) + 5
Women:
BMR = (10 × weight_kg) + (6.25 × height_cm) − (5 × age) − 161
The formula uses total bodyweight. This works well for people within a normal body fat range. If you are significantly above average body fat, Mifflin-St Jeor will overestimate BMR somewhat, because it treats all weight as metabolically equivalent when fat tissue burns fewer calories per kilogram than muscle. The Katch-McArdle formula corrects for this using lean body mass, but it requires body composition data most people do not have.
Step 3: Choose Your Activity Multiplier
The activity multiplier (also called the PAL — Physical Activity Level) converts BMR into TDEE by accounting for everything you do during the day.
| Activity Level | Multiplier | Who It Applies To |
|---|---|---|
| Sedentary | 1.2 | Desk job, no intentional exercise, mostly sitting |
| Lightly active | 1.375 | Light exercise 1–3 days per week |
| Moderately active | 1.55 | Moderate exercise 3–5 days per week |
| Very active | 1.725 | Hard exercise 6–7 days per week |
| Extra active | 1.9 | Physical job + daily training, or professional athletes |
The most important practical note: most people underestimate their activity level. Someone who walks to work, takes stairs, and does light gym sessions 3 days per week is lightly to moderately active, not sedentary. Choosing too low a multiplier produces an underestimated TDEE, which leads to an unnecessarily aggressive calorie target.
When uncertain, start with the multiplier that feels slightly too high. You can recalibrate based on real-world results (covered in Step 5).
Step 4: Calculate TDEE = BMR × Activity Multiplier
TDEE = BMR × Activity Multiplier
This single multiplication converts your resting metabolic rate into a complete picture of daily energy expenditure.
Worked example — 25-year-old male, 75 kg, 178 cm, moderately active:
- BMR = (10 × 75) + (6.25 × 178) − (5 × 25) + 5
- BMR = 750 + 1,112 − 125 + 5
- BMR = 1,742 kcal
- TDEE = 1,742 × 1.55
- TDEE = 2,700 kcal/day
This means the person burns approximately 2,700 kcal on an average moderately active day. To maintain weight, they eat 2,700 kcal. To lose weight, they eat less. To gain muscle, they eat more.
The TDEE Calculator performs this calculation instantly — enter your details and get the result without manual arithmetic.
Step 5: Use TDEE to Set Calorie Goals
TDEE is not a goal in itself — it is the baseline from which you set a calorie target based on what you want to achieve.
| Goal | Calorie Target | Expected Rate |
|---|---|---|
| Weight loss | TDEE − 300 to 500 kcal | 0.25–0.45 kg/week |
| Aggressive weight loss | TDEE − 700 to 1,000 kcal | 0.65–0.9 kg/week (use cautiously) |
| Maintenance | TDEE | Stable weight |
| Lean muscle gain | TDEE + 200 to 400 kcal | Slow, quality muscle gain |
For our example (TDEE 2,700 kcal):
- Maintenance: 2,700 kcal
- Weight loss (−500): 2,200 kcal
- Lean bulk (+300): 3,000 kcal
After 2–3 weeks of eating at the chosen target, check whether your weight trend matches expectations. If weight is stable when you expected to lose, reduce by 100–150 kcal. If you are losing faster than 1% bodyweight per week, increase by 100–150 kcal.
Common Mistakes to Avoid
Underestimating activity level. This is the single most common TDEE error. People with desk jobs who exercise 4 times per week routinely choose "sedentary" instead of "moderately active," understating their TDEE by 300–400 kcal. The result is a calorie target that feels impossible to maintain because it is artificially low. If your eating feels sustainable but weight is still dropping faster than expected, you likely underestimated your activity level.
Not recalculating after significant weight loss. TDEE falls as bodyweight falls. A 90 kg person losing 15 kg reduces their TDEE by roughly 200–250 kcal. Continuing to use the TDEE calculated at 90 kg when you weigh 75 kg means your actual deficit is smaller than intended — explaining why progress often slows after the first month or two of dieting.
Using Harris-Benedict. The Harris-Benedict equation was developed in 1919 and is known to overestimate BMR, particularly for heavier individuals. Modern research consistently finds Mifflin-St Jeor to be more accurate. Use Mifflin-St Jeor as the default, or Katch-McArdle if you have reliable body composition data.
Ignoring NEAT. Non-Exercise Activity Thermogenesis — all the movement that is not formal exercise — can account for 15–50% of TDEE. People who sit for long periods have significantly lower NEAT than people who stand, walk, or move frequently. A person who works at a standing desk and walks frequently has a meaningfully higher TDEE than someone who sits for 8 hours, even if both do the same structured workout. NEAT also declines during calorie restriction as the body conserves energy, which is a major contributor to weight loss plateaus.
Trusting fitness tracker calorie estimates. Wearable devices overestimate calorie burn by an average of 20–40% in research studies. If you use a fitness tracker to add exercise calories to your TDEE, apply a 50–70% discount to the device's estimate to avoid cancelling out your intended deficit.
Formula & Methodology
Mifflin-St Jeor BMR formulas:
- 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: TDEE = BMR × Activity Multiplier
Worked example — 25-year-old male, 75 kg, 178 cm, moderately active:
- BMR = 750 + 1,112 − 125 + 5 = 1,742 kcal
- TDEE = 1,742 × 1.55 = 2,700 kcal
The Mifflin-St Jeor equation is accurate within ±10% for approximately 80% of the general population in a normal weight range. It is the formula recommended by the Academy of Nutrition and Dietetics for clinical use. For the specific subset of people with known lean body mass, Katch-McArdle (BMR = 370 + (21.6 × lean_mass_kg)) provides improved accuracy because it removes the confounding effect of varying body fat percentage.
Contextualise your TDEE against your BMI Calculator result and body composition goals to get a full picture of your energy needs relative to your current health status.