TDEE Calculator

What is TDEE

What is TDEE?

TDEE (Total Daily Energy Expenditure) is the total number of calories your body burns in a 24-hour period. It includes everything from breathing and digesting food to walking and exercising.

Knowing your TDEE is the foundation of any diet plan: eat less than your TDEE to lose weight, eat more to gain weight, or match it to maintain your current weight. Unlike BMR, TDEE accounts for your real-world activity level.

Components

The 3 Components of TDEE

BMR — Basal Metabolic Rate (~60-70%)

The largest component of your TDEE. BMR is the energy your body needs just to stay alive — powering your brain, heart, lungs, and other organs. Even if you stayed in bed all day, you'd still burn this many calories.

TEF — Thermic Effect of Food (~10%)

The energy required to digest, absorb, and process the food you eat. Protein has the highest thermic effect (20-30%), followed by carbs (5-10%) and fat (0-3%). This is why high-protein diets can slightly boost your metabolism.

Physical Activity (~20-30%)

This includes both intentional exercise (EAT — Exercise Activity Thermogenesis) and non-exercise activity (NEAT — walking, fidgeting, standing). NEAT can vary by up to 2,000 calories/day between individuals and is often the most modifiable component.

How It Works

How the TDEE Calculator Works

This calculator uses the Mifflin-St Jeor equation (1990) to estimate your Basal Metabolic Rate (BMR) — the calories your body needs at complete rest. It then multiplies your BMR by an activity factor to calculate your TDEE.

The Mifflin-St Jeor equation was found to be the most accurate predictive equation for healthy individuals in a systematic review of 18 studies by Frankenfield et al., published in the Journal of the American Dietetic Association (2005). It predicts resting metabolic rate within 10% of measured values in more subjects than any other equation.

Formula	Equation	Accuracy
Mifflin-St Jeor (default)	10×W + 6.25×H - 5×A ± s	Most accurate (ADA)
Harris-Benedict (revised)	13.4×W + 4.8×H - 5.7×A + 88.4 (M)	Tends to overestimate
Katch-McArdle	370 + 21.6×LBM	Best for athletes (needs body fat %)

Level	Description	Multiplier
Sedentary	Little or no exercise, desk job	×1.2
Lightly Active	Light exercise 1-3 days/week	×1.375
Moderately Active	Moderate exercise 3-5 days/week	×1.55
Very Active	Hard exercise 6-7 days/week	×1.725
Extra Active	Very intense exercise, physical job	×1.9

Formulas Explained

BMR Formulas: How They Work

This calculator supports three scientifically validated formulas for estimating your Basal Metabolic Rate (BMR). Each has different strengths and is better suited for different body types.

1. Mifflin-St Jeor (1990) — Recommended

Developed in 1990 by Mifflin and St Jeor, this is the most widely recommended equation. A 2005 systematic review by Frankenfield et al. in the Journal of the American Dietetic Association found it to be the most accurate for healthy adults, predicting BMR within ±10% in more subjects than any other formula.

Men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5

Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161

Best for: Most healthy adults. This is the default formula used by dietitians and nutrition professionals worldwide.

2. Harris-Benedict (1984, Revised)

Originally developed in 1919 by Harris and Benedict, this was the gold standard for decades. The 1984 revision by Roza and Shizgal improved accuracy, but studies show it still tends to overestimate BMR by 5-15%, especially in obese individuals.

Men: BMR = 88.362 + 13.397 × weight(kg) + 4.799 × height(cm) − 5.677 × age

Women: BMR = 447.593 + 9.247 × weight(kg) + 3.098 × height(cm) − 4.33 × age

Best for: Historical comparison. If you've been tracking with Harris-Benedict, you may want to continue for consistency, but know it likely overestimates your BMR.

3. Katch-McArdle

Unlike the other formulas, Katch-McArdle uses lean body mass (LBM) instead of total weight, making it gender-neutral. This makes it particularly accurate for athletes and people who know their body fat percentage.

BMR = 370 + 21.6 × lean body mass (kg)

LBM = weight(kg) × (1 − body fat % / 100)

Best for: Athletes, bodybuilders, and anyone who knows their body fat percentage. If you have above-average muscle mass, this formula will be more accurate than Mifflin-St Jeor.

All three formulas estimate BMR only — the calories your body burns at rest. To get your TDEE, the calculator multiplies your BMR by an activity factor. The activity multiplier is the same regardless of which BMR formula you choose.

TDEE vs BMR

TDEE vs BMR — What's the Difference?

Many people confuse TDEE and BMR. Here's the key difference:

	BMR	TDEE
Measures	Calories at complete rest	Total daily calories burned
Includes activity?	No	Yes
Use for dieting?	No — too low for planning	Yes — base your diet on this
Typical value	1,400–1,800 kcal	1,800–3,000 kcal

Bottom line: Always use TDEE (not BMR) to plan your calorie intake. Eating at your BMR would mean a severe calorie deficit that's unsustainable and potentially unhealthy.

The Science

Why Tracking Calories Works

Research consistently shows that people who track what they eat are significantly more successful at losing weight:

Study	Finding	Source
Kaiser Permanente (2008)	People who kept daily food records lost 2× more weight	Am J Prev Med
Harvey et al. (2019)	Only 15 min/day of food logging needed for results	Obesity
Berry et al. (2021)	Digital self-monitoring = -2.87 kg significant weight loss	Obesity Reviews
Huntriss et al. (2024)	50% of active users achieved 5%+ weight loss	Obesity Sci & Pract
AI-Assisted Tracking (2024)	64% maintain changes vs 23% manual tracking	JMIR

"Those who kept daily food records lost twice as much weight as those who kept no records."
— Jack Hollis, Ph.D., Kaiser Permanente

FAQ

Frequently Asked Questions

What is TDEE and why does it matter?

TDEE (Total Daily Energy Expenditure) is the total number of calories your body burns per day, including all activity. It matters because it determines whether you lose, maintain, or gain weight. Eat below your TDEE to lose weight, above it to gain weight.

How is TDEE calculated?

TDEE is calculated by first estimating your BMR (Basal Metabolic Rate) using the Mifflin-St Jeor equation, then multiplying it by an activity factor (1.2 for sedentary up to 1.9 for very active). The Mifflin-St Jeor equation was validated as the most accurate by the Academy of Nutrition and Dietetics.

What is the difference between TDEE and BMR?

BMR is the calories your body burns at complete rest — just to keep you alive. TDEE is your BMR plus all additional energy burned through daily activity and exercise. TDEE is always higher than BMR and is the number you should use for diet planning.

How accurate is the TDEE calculator?

The Mifflin-St Jeor equation predicts BMR within ±10% for most healthy adults. However, TDEE estimation also depends on correctly assessing your activity level. Use the result as a starting point and adjust based on your actual weight changes over 2-3 weeks.

Should I eat at my TDEE or below it?

It depends on your goal. To maintain weight, eat at your TDEE. To lose weight, eat 300-500 kcal below your TDEE (moderate deficit). To gain muscle, eat 250-500 kcal above your TDEE with adequate protein and strength training.

Why is my TDEE different from other calculators?

Different calculators use different formulas. We use Mifflin-St Jeor (1990), which is the most accurate according to a 2005 meta-analysis. Some calculators use the older Harris-Benedict equation, which tends to overestimate. Activity multipliers also vary between calculators.

How often should I recalculate my TDEE?

Recalculate your TDEE whenever your weight changes by 5+ kg, your activity level changes significantly, or every 2-3 months during a weight loss journey. As you lose weight, your TDEE decreases — this is why weight loss plateaus happen.

Can I increase my TDEE?

Yes. The most effective ways are: (1) increase physical activity, especially strength training which builds muscle and raises BMR, (2) increase NEAT — walk more, take stairs, stand at your desk, (3) eat adequate protein, which has a higher thermic effect. Building muscle is the best long-term strategy.

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