Overview
TDEE, short for Total Daily Energy Expenditure, is the single most useful number in nutrition planning. It tells you how many calories your body burns across an entire day, accounting for everything from sleep to formal exercise to the walk to your desk. Every calorie target worth setting, whether for weight loss, muscle gain, or maintenance, comes from TDEE.
The catch is that you can't measure TDEE directly without lab equipment. Instead, it gets estimated in two steps: first computing your Basal Metabolic Rate (BMR) with a validated formula, then multiplying by an activity factor that reflects your lifestyle. This guide walks through that calculation, with the formulas, the activity multiplier table, a worked numerical example, and the mistakes that most often throw the result off.
Use the TDEE Calculator to run this automatically, or work through the steps below if you want to understand the method behind the number.
What You Need
- Your current weight in kilograms
- Your height in centimeters
- Your age in years
- An honest read on 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. Stay in bed, perfectly still, for 24 hours and you'd burn approximately your BMR in calories.
TDEE takes BMR and scales it up based on how active you actually are. Walking to the kitchen, commuting, exercising, doing chores, fidgeting: all of it burns calories on top of BMR. TDEE captures the whole picture.
The practical upshot: BMR alone never makes a good calorie target. A sedentary person eats around 20% above BMR just to hold steady. An active person eats 60-90% above it.
The BMR Calculator isolates that first step if you want to check the number on its own before moving forward.
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, which works fine for people within a normal body fat range. If your body fat runs well above average, Mifflin-St Jeor will overestimate BMR somewhat, since it treats all weight as metabolically equal when fat tissue actually burns fewer calories per kilogram than muscle. Katch-McArdle corrects for this using lean body mass, but it needs body composition data most people don't have handy.
Step 3: Choose Your Activity Multiplier
The activity multiplier, also called 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 plus daily training, or professional athletes |
Most people underestimate their own activity level, and that's the single most common source of error here. Someone who walks to work, takes stairs, and hits light gym sessions three days a week is lightly to moderately active, not sedentary. Pick too low a multiplier and you'll understate TDEE, which leaves you chasing a calorie target that's needlessly aggressive.
When you're unsure, lean toward the multiplier that feels slightly too high. You can recalibrate later based on real-world results, covered in Step 5.
Step 4: Calculate TDEE = BMR × Activity Multiplier
TDEE = BMR × Activity Multiplier
One multiplication turns your resting metabolic rate into a full 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 person burns roughly 2,700 kcal on an average moderately active day. To hold steady, they eat 2,700 kcal. To lose weight, they eat less. To build muscle, they eat more.
The TDEE Calculator runs this instantly. Enter your details and skip the manual arithmetic.
Step 5: Use TDEE to Set Calorie Goals
TDEE isn't a goal by itself. It's the baseline you build a calorie target from, depending on what you're after.
| 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 eating at your chosen target, check whether the weight trend matches what you expected. Weight holding steady when you expected loss means cut another 100-150 kcal. Losing faster than 1% bodyweight per week means add 100-150 kcal back.
Common Mistakes to Avoid
Underestimating activity level. This is the single most common TDEE error. People with desk jobs who exercise four times a week routinely pick "sedentary" over "moderately active," understating TDEE by 300-400 kcal. The result is a calorie target that feels impossible to stick to because it's artificially low. If your eating feels sustainable but the scale keeps dropping faster than expected, you probably underestimated your activity level.
Skipping the recalculation after real weight loss. TDEE falls as bodyweight falls. A 90 kg person who drops 15 kg cuts their TDEE by roughly 200-250 kcal. Keep using the TDEE calculated at 90 kg once you're down to 75 kg and your actual deficit ends up smaller than intended, which explains why progress often slows a month or two into a diet.
Using Harris-Benedict. This equation dates to 1919 and is known to overestimate BMR, particularly for heavier individuals. Modern research consistently finds Mifflin-St Jeor more accurate. Default to Mifflin-St Jeor, or use Katch-McArdle if you have reliable body composition data.
Ignoring NEAT. Non-Exercise Activity Thermogenesis, all the movement outside formal exercise, can make up 15-50% of TDEE. People who sit for long stretches carry noticeably lower NEAT than people who stand, walk, or move around often. Someone working at a standing desk who walks frequently ends up with a meaningfully higher TDEE than someone sitting for eight hours, even doing the identical structured workout. NEAT also drops during calorie restriction as the body conserves energy, a major driver of weight loss plateaus.
Trusting fitness tracker calorie estimates. Wearable devices overestimate calorie burn by 20-40% on average across research studies. If you're adding tracker-reported exercise calories to your TDEE, discount the device's number by 50-70% or you'll cancel out the deficit you intended.
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
Mifflin-St Jeor lands within roughly plus or minus 10% for about 80% of the general population in a normal weight range, and the Academy of Nutrition and Dietetics recommends it for clinical use. For the subset of people with known lean body mass, Katch-McArdle (BMR = 370 + (21.6 × lean_mass_kg)) improves on that accuracy by removing the confounding effect of varying body fat percentage.
Weigh your TDEE against your BMI Calculator result and your broader body composition goals to get the full picture of your energy needs.