Calorie & TDEE Calculator
Mifflin-St Jeor · Most Accurate Formula
yrs
ft
in
lbs
cm
kg
Enter your details to see your daily calorie needs and TDEE.
Maintenance Calories (TDEE)
0
calories per day
Lose 1 lb/wk
0
−500 cal/day
Maintain
0
Current TDEE
Lean Bulk
0
+250 cal/day
Lose 2 lbs/wk
0
−1,000 cal/day
BMR (at complete rest)
0 cal/day
Calories by Activity Level
Suggested Macros (Maintenance)
Protein (30%)—
Carbohydrates (40%)—
Fat (30%)—
Protein target—
TDEE & Calorie Needs Explained
A moderately active 30-year-old man who is 5'9" and 160 lb burns about 2,598 calories a day, and a woman of the same age at 5'4" and 140 lb about 2,077. That is maintenance, or TDEE. The calculator estimates your BMR with the Mifflin-St Jeor equation, multiplies it by your activity level, and shows targets to lose, keep or gain weight.
Your BMR (Basal Metabolic Rate) is the calories your body burns at complete rest to sustain basic life functions. This calculator uses the Mifflin-St Jeor equation (1990), the most accurate formula validated by multiple clinical studies. Multiplied by your activity factor, it gives your TDEE: the total calories you actually burn each day.
To lose fat, eat below your TDEE. To build muscle, eat above it. The rate of change depends on the size of your deficit or surplus. A 500 calorie/day deficit produces approximately 1 pound of fat loss per week (3,500 cal = 1 lb fat). A 250-calorie surplus for a lean bulk minimizes fat gain while supporting muscle growth.
How Many Calories to Lose Weight
Create a deficit of 500 cal/day below TDEE to lose ~1 lb/week. A 250 cal deficit = 0.5 lb/week (more sustainable). Maximum safe deficit: 1,000 cal/day (2 lbs/week). Never go below 1,200 cal/day (women) or 1,500 cal/day (men) without medical supervision. Too large a deficit accelerates muscle loss and triggers metabolic adaptation.
How Many Calories to Gain Muscle
A lean bulk uses a 200-300 calorie surplus above TDEE combined with progressive resistance training and 1.6-2.2g protein per kg of body weight. Natural muscle gain rate: 0.5-2 lbs/month. Larger surpluses build muscle faster but add more fat. Beginners can often gain muscle at maintenance (body recomposition) due to higher training response.
Choosing the Right Activity Level
The most common mistake is overestimating activity level. "Moderately active" means 3-5 true workout sessions per week, not a general sense of busyness. If you have a desk job and exercise 3x/week, you are likely "lightly active" (1.375). Honest activity level selection is the single most impactful factor in TDEE accuracy. When in doubt, go one level lower.
Tracking Progress and Adjusting
TDEE formulas have a 10-15% individual error margin. Track weight for 3-4 weeks at a given calorie level. If not losing weight as expected, reduce by 100-200 calories. If losing faster than desired (muscle risk), increase by 100-200 calories. Weigh yourself under the same conditions each day (morning, after bathroom) and use a 7-day average to smooth water weight fluctuations.
Maintenance Calories by Size, Age and Activity
Calories a day to keep your current weight (TDEE), computed with Mifflin-St Jeor and the same five activity factors the calculator uses.
| Person | Age | Sedentary | Light | Moderate | Very active | Extra active |
|---|---|---|---|---|---|---|
| Woman, 5'4", 140 lb | 30 | 1,608 | 1,843 | 2,077 | 2,312 | 2,546 |
| Woman, 5'4", 140 lb | 50 | 1,488 | 1,705 | 1,922 | 2,139 | 2,356 |
| Woman, 5'6", 170 lb | 30 | 1,809 | 2,073 | 2,337 | 2,601 | 2,865 |
| Woman, 5'6", 170 lb | 50 | 1,689 | 1,936 | 2,182 | 2,429 | 2,675 |
| Man, 5'9", 160 lb | 30 | 2,011 | 2,305 | 2,598 | 2,891 | 3,185 |
| Man, 5'9", 160 lb | 50 | 1,891 | 2,167 | 2,443 | 2,719 | 2,995 |
| Man, 5'11", 200 lb | 30 | 2,267 | 2,598 | 2,928 | 3,259 | 3,590 |
| Man, 5'11", 200 lb | 50 | 2,147 | 2,460 | 2,773 | 3,087 | 3,400 |
Activity factors: sedentary 1.2, light 1.375, moderate 1.55, very active 1.725, extra active 1.9. Twenty extra years lowers BMR by 100 calories in this formula, so the gap grows with activity.
Worked Example: From BMR to a Goal
Take the calculator's default: a 30-year-old man, 5'9" (175.3 cm) and 160 lb (72.6 kg), moderately active.
- BMR = 10 × 72.6 + 6.25 × 175.3 − 5 × 30 + 5 = 1,676 calories.
- TDEE = 1,676 × 1.55 = 2,598 calories.
- Apply the goal adjustment from the table below.
| Goal | Daily change | Target for this man |
|---|---|---|
| Lose 0.5 lb a week | 250 fewer | 2,348 |
| Lose 1 lb a week | 500 fewer | 2,098 |
| Lose 2 lb a week | 1,000 fewer | 1,598 |
| Maintain | none | 2,598 |
| Lean bulk | 250 more | 2,848 |
A woman with the same age, height, weight and activity gets a BMR of 1,510 and a TDEE of 2,341, because the formula's sex constant differs by 166 calories. Her 2 lb a week target would be 1,341, which stays above the 1,200 floor.
How Accurate Is Your Number?
Mifflin-St Jeor predicts resting burn within 10% for most adults, but not all. For the man above, 10% is about 260 calories a day either way. Two things move the result more than the formula does:
- Activity level. Choosing "moderate" when "light" fits better adds 293 calories to his TDEE (2,598 versus 2,305), more than half of a 500 calorie deficit.
- Body composition. A very muscular person burns more than the formula predicts. If you know your body fat, the BMR calculator and lean body mass calculator help.
Treat the result as a starting point. Eat at the target for three to four weeks, compare the trend of your weight with what you expected, and adjust by 100 to 200 calories. For a detailed weight loss plan, use the calorie deficit calculator. These are estimates; a doctor or registered dietitian can help if you have a medical condition, are pregnant or are under 18.
Method and sources. BMR: Mifflin-St Jeor equation (Mifflin et al., American Journal of Clinical Nutrition, 1990): 10 × kg + 6.25 × cm − 5 × age, +5 for men, −161 for women. TDEE = BMR × activity factor. Every table value was computed with that formula. Accuracy: Frankenfield et al., Journal of the American Dietetic Association, 2005. Metabolic adaptation: Rosenbaum and Leibel, International Journal of Obesity, 2010. Calorie floors: 2013 AHA/ACC/TOS adult obesity guideline. Estimates only, not medical advice.
Calorie calculations are estimates with approximately 10-15% individual variation. Results may differ based on body composition, hormones, medications, and genetics. Consult a healthcare professional or registered dietitian before making significant dietary changes.
Calorie & TDEE Questions
TDEE (Total Daily Energy Expenditure) is the total calories your body burns in a day, including basal metabolism, digestion, and physical activity. It is calculated by multiplying BMR by an activity factor: sedentary (×1.2), lightly active (×1.375), moderately active (×1.55), very active (×1.725), or extra active (×1.9). TDEE is the foundation of any calorie-based nutrition plan. Eating at TDEE maintains weight; below TDEE creates a deficit for fat loss; above TDEE creates a surplus for muscle gain.
One pound of fat contains approximately 3,500 calories. To lose 1 lb/week, you need a 500 calorie daily deficit (500 × 7 = 3,500). To lose 0.5 lbs/week, a 250 calorie deficit. To lose 2 lbs/week, a 1,000 calorie deficit. Most experts recommend losing no more than 1-1.5 lbs/week for most people, as faster loss increases the risk of losing lean muscle. Never eat below 1,200 cal/day (women) or 1,500 cal/day (men) for extended periods without medical supervision.
The Mifflin-St Jeor equation (1990) is widely considered the most accurate for the general population. A landmark 2005 study in the Journal of the American Dietetic Association found it predicted resting metabolic rate within 10% in 82% of non-obese adults and 70% of adults with obesity, outperforming the older Harris-Benedict equation (which overestimates by about 5%). For highly muscular or athletic individuals with known body fat percentage, the Katch-McArdle formula (using lean body mass) may be more accurate. For obese individuals, Mifflin-St Jeor using actual body weight is generally more reliable than ideal weight-based adjustments.
The most common reasons: (1) Overestimating activity level, this is the most frequent error; a desk job with 3 gym sessions per week is lightly active, not moderately. (2) Inaccurate food tracking: studies consistently show people underestimate calorie intake by 20-40%, especially from cooking fats, sauces, and snacks. (3) Metabolic adaptation: after weeks of dieting, total daily burn can run about 10 to 15% below what your new weight predicts, mostly because you move less. (4) Water retention masking fat loss: weight can stay stable for weeks while fat is being lost due to water retention from stress, hormones, or sodium. Track for 4 weeks then adjust by 100-200 calories if progress stalls.
For a lean bulk: eat 200-300 calories above TDEE. This provides energy for muscle synthesis while minimizing fat gain. Combined with progressive resistance training and 1.6-2.2g protein per kg of body weight, this approach builds muscle at approximately 0.5-2 lbs per month for natural lifters. A more aggressive surplus of 500 cal/day builds faster but adds significantly more fat. Note: beginners ("newbie gains") and people returning after a break can often achieve body recomposition at maintenance calories or even a slight deficit, gaining muscle while losing fat simultaneously.
Yes: this is called metabolic adaptation or adaptive thermogenesis. When calories are restricted for months, total daily burn can fall about 10 to 15% more than weight loss alone explains; only part of that is a lower BMR. The body also reduces NEAT (non-exercise activity thermogenesis: fidgeting, posture, general movement) which can reduce calorie burn by another 100-300 calories/day. Strategies to minimize adaptation: avoid deficits greater than 25% of TDEE, take diet breaks (return to maintenance for 1-2 weeks every 4-6 weeks), maintain protein intake (1.8-2.4g/kg during aggressive deficits), and prioritize resistance training to preserve lean muscle mass.
Significantly. Lean muscle mass (not total body weight) is the primary driver of metabolic rate. Muscle burns approximately 3 times more calories at rest than fat tissue (roughly 6 cal/lb/day for muscle vs 2 cal/lb for fat). Two people of identical age, height, and weight but different body compositions can have BMRs that differ by 200-400 calories per day. This is why highly muscular individuals have higher calorie needs than the formula predicts from weight alone. For lean/athletic individuals, the Katch-McArdle formula (BMR = 370 + 21.6 × lean body mass in kg) is more accurate than height/weight-based formulas.
Macros (macronutrients) are protein, carbohydrates, and fat. Each provides calories: protein = 4 cal/g, carbohydrates = 4 cal/g, fat = 9 cal/g. A common starting point for body recomposition: protein 30% of calories (roughly 1.6g per kg of body weight), carbohydrates 40%, fat 30%. For fat loss, increasing protein to 35-40% of calories helps preserve lean mass and increases satiety. For endurance athletes, carbohydrates may increase to 50-60%. For low-carb approaches, fat increases to 50-60%. There is no single "correct" macro ratio: total calorie intake relative to TDEE matters most, but macros influence body composition and hunger within the same calorie budget.
Formula-based TDEE calculators have approximately 10-15% individual variation from actual measured values. Sources of inaccuracy: individual metabolic variation not captured by height/weight/age, body composition differences (muscular vs. overfat at same weight), hormonal differences (thyroid function, insulin sensitivity), chronic medication use, and particularly the subjective nature of activity level selection. For most people, the formula provides a reasonable starting point. The key is to treat the number as an initial estimate, track actual weight change for 3-4 weeks, and adjust by 100-200 calories up or down based on real results rather than assuming the formula is perfectly accurate for your individual metabolism.
It depends on how you set your TDEE. If you used a higher activity multiplier that already accounts for your exercise (e.g., "very active" for daily hard training), your TDEE already includes those calories and you should not eat them back. If you used "sedentary" and then exercise, you may eat back 50-75% of estimated exercise calories (not 100%, as exercise calorie estimates are notoriously inaccurate and tend to overestimate by 50-100%). The simplest approach for most people: use a moderate activity multiplier that reflects your average weekly activity, eat at that TDEE consistently, and don't try to adjust day-by-day based on individual workout sessions.
It depends on size, age and activity. A 30-year-old woman who is 5'4" and 140 lb needs about 1,608 calories if sedentary and 2,077 if moderately active to keep her weight. At age 50 those figures are 1,488 and 1,922. To lose about 1 lb a week, subtract 500, but stay at or above 1,200 calories a day unless a doctor advises otherwise.
A 30-year-old man who is 5'9" and 160 lb needs about 2,011 calories if sedentary and 2,598 if moderately active. A 5'11", 200 lb man of the same age needs about 2,267 to 2,928 across those activity levels. To lose about 1 lb a week, subtract 500, keeping intake at or above 1,500 calories a day.