What is a TDEE calculator?
A TDEE calculator estimates your Total Daily Energy Expenditure — the number of calories you burn every day. It is the most important number in nutrition, because every goal (fat loss, muscle gain, maintenance) requires you to eat a specific amount relative to it.
TDEE has two components: your BMR (Basal Metabolic Rate — the calories your body burns at complete rest) multiplied by an activity factor. This calculator supports three BMR formulas, each with different accuracy profiles for different populations.
Which TDEE formula is most accurate?
This calculator offers three validated BMR equations. Here is how they compare:
| Formula | Accuracy | Best for | Requires |
|---|---|---|---|
| Mifflin-St Jeor | ~10% error | General population — recommended default | Age, height, weight, sex |
| Harris-Benedict | ~12–15% error | Historical reference, slightly less precise | Age, height, weight, sex |
| Katch-McArdle | ~8% error* | Athletes and lean individuals | Body fat percentage |
* Katch-McArdle accuracy assumes an accurate body fat % measurement. Use DEXA or a calibrated skinfold protocol for best results.
Mifflin-St Jeor:
Men: BMR = 10×W + 6.25×H − 5×A + 5
Women: BMR = 10×W + 6.25×H − 5×A − 161
Harris-Benedict (revised):
Men: BMR = 88.362 + 13.397×W + 4.799×H − 5.677×A
Women: BMR = 447.593 + 9.247×W + 3.098×H − 4.330×A
Katch-McArdle:
BMR = 370 + 21.6 × LBM (LBM = W × (1 − BF%))
W = weight (kg) · H = height (cm) · A = age (years) · LBM = lean body mass (kg)
Activity level guide — including daily steps
The activity multiplier is the largest source of TDEE estimation error. Most people overestimate their activity level. When in doubt, choose one level lower and adjust after tracking your weight for 2–3 weeks.
| Level | Multiplier | Daily steps | Typical profile |
|---|---|---|---|
| Sedentary | ×1.2 | < 5,000 | Desk job, drives everywhere, no structured exercise |
| Lightly active | ×1.375 | 5,000–7,500 | Light gym 1–3×/week or daily walking commute |
| Moderately active | ×1.55 | 7,500–10,000 | Gym 3–5×/week, moderately active job |
| Very active | ×1.725 | 10,000–12,500 | Hard training 6–7×/week, manual work |
| Extra active | ×1.9 | > 12,500 | Physical job + twice-daily training or elite athlete |
TDEE for weight loss — calorie deficit guide
A calorie deficit is the only mechanism for fat loss. The size of the deficit determines the rate:
- −250 kcal/day~0.25 kg/week · Sustainable, minimal muscle loss, best for lean individuals
- −500 kcal/day~0.5 kg/week · Recommended rate — balances speed with muscle preservation
- −750 kcal/day~0.75 kg/week · Aggressive — increase protein to 2.2g/kg to limit muscle loss
- −1,000 kcal/day~1 kg/week · Maximum recommended — requires monitoring and high protein intake
Frequently asked questions
What is a TDEE calculator?
A TDEE calculator estimates the total calories your body burns in a day — your Basal Metabolic Rate (calories burned at rest) multiplied by an activity factor. TDEE is the single most important number for any nutrition goal: eat below it to lose fat, above it to gain muscle, or match it to maintain weight.
Which TDEE formula is most accurate?
Mifflin-St Jeor (1990) is the most accurate for the general population and is recommended by the Academy of Nutrition and Dietetics. It outperforms Harris-Benedict in multiple validation studies, with an average error of ~10%. Katch-McArdle is more accurate if you know your body fat percentage, because it calculates BMR from lean mass directly, bypassing the gender offset.
What is the difference between BMR and TDEE?
BMR (Basal Metabolic Rate) is the calories your body burns at complete rest — just to sustain breathing, circulation, and organ function. TDEE adds the energy cost of all daily movement and exercise. TDEE is always higher than BMR. For most people, TDEE is 1.2–1.9× their BMR depending on activity level.
How accurate is a TDEE calculator?
TDEE calculators based on Mifflin-St Jeor are accurate to within 10–15% for most people. The main source of error is the activity multiplier — most people overestimate their activity level. Start with the conservative (lower) activity estimate, track your weight for 2–3 weeks, and adjust by ±100–200 kcal based on observed results.
How many calories should I eat to lose weight?
A deficit of 500 kcal/day below your TDEE produces roughly 0.5 kg (1 lb) of fat loss per week. A 250 kcal deficit gives slower, more sustainable results. Avoid exceeding a 1,000 kcal/day deficit — this risks muscle loss and metabolic adaptation. The safest approach is 0.5–1% of bodyweight loss per week.
How many calories do I need to build muscle?
A surplus of 200–300 kcal/day above TDEE is the sweet spot for lean muscle gain with minimal fat accumulation. Larger surpluses (500+ kcal) increase fat gain proportionally without meaningfully faster muscle growth, since muscle protein synthesis has a ceiling rate. Pair any surplus with progressive resistance training.
Does TDEE change over time?
Yes. As your weight, muscle mass, age, or activity level change, your TDEE shifts. Losing weight reduces TDEE (you weigh less, so you burn fewer calories). Building muscle increases it slightly. Recalculate every 4–8 weeks or whenever your weight changes by more than 3–5 kg.
How can I use daily steps to estimate activity level?
Steps are a reasonable proxy for activity level: under 5,000 steps/day is sedentary; 5,000–7,500 is lightly active; 7,500–10,000 is moderately active; 10,000–12,500 is very active; above 12,500 is extra active. These thresholds assume a typical desk job — add exercise sessions on top of your step count.
What macros should I eat at my TDEE?
A common balanced starting point is 30% protein, 40% carbohydrates, and 30% fat. For body composition goals, protein is the priority: aim for 1.6–2.2g per kg of bodyweight. Once protein is set, distribute remaining calories between carbs and fat based on preference and performance — there is no single optimal ratio.
Why does Katch-McArdle give a different result than Mifflin?
Katch-McArdle calculates BMR from lean body mass (LBM) rather than total body weight, age, and sex. This means it ignores the gender offset and focuses purely on metabolically active tissue. A muscular person with low body fat will get a higher BMR from Katch-McArdle than from Mifflin-St Jeor, because their LBM is high relative to total weight.