Calculate your TDEE and BMR using the Mifflin-St Jeor equation — the most accurate formula recommended by the Academy of Nutrition and Dietetics. Get precise calorie targets for weight loss, maintenance, and muscle gain based on your activity level.
✓Formula: Mifflin MD & St Jeor ST, Am J Clin Nutr 1990;51(2):241–7 — April 2026
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ft
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in
kg
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cm
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yrs
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When in doubt, choose one level lower than you think
Your TDEE (Maintenance Calories)
--
calories per day to maintain your current weight
Your BMR
--
calories at rest
TDEE
--
maintenance
Weight Loss
--
−500 cal/day
Lean Bulk
--
+300 cal/day
🔥
Fat Loss
--
~1 lb/week loss (500 cal deficit)
⚖️
Maintenance
--
Hold current weight (eat at TDEE)
💪
Lean Bulk
--
Slow muscle gain (300 cal surplus)
📊 All Activity Level Estimates for Your Stats
Sedentary (x1.2)--
Lightly Active (x1.375)--
Moderately Active (x1.55)--
Very Active (x1.725)--
Extra Active (x1.9)--
⚠️ Important: TDEE calculations are estimates with an accuracy of ±10–15%. Actual calorie needs vary due to individual metabolic differences, genetics, medical conditions, and medications. Do not use this calculator as a substitute for advice from a registered dietitian or healthcare provider. Never eat below your BMR without medical supervision.
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Formula Sources & References
✓TDEE and BMR formulas verified against peer-reviewed publications. This calculator uses the Mifflin-St Jeor equation, recommended by the Academy of Nutrition and Dietetics as the most accurate for healthy adults.
Original peer-reviewed publication introducing the Mifflin-St Jeor equation. Validated against measured resting energy expenditure in healthy adults. This is the primary source for the BMR formulas used in this calculator.
Systematic review of predictive BMR equations. Confirmed the Mifflin-St Jeor equation is more likely than Harris-Benedict and other equations to predict resting metabolic rate within 10% of measured values. Source for accuracy claims and formula selection rationale.
Clinical reference confirming activity multipliers: Sedentary ×1.2, Lightly active ×1.375, Moderately active ×1.55, Active ×1.725, Extra active ×1.9. Used to verify multiplier values used in this TDEE calculator.
TDEE Explained: How to Calculate Total Daily Energy Expenditure
TDEE — Total Daily Energy Expenditure — is the most important number in any nutrition plan. It tells you exactly how many calories your body burns in a day, accounting for everything from breathing to exercise. Without knowing your TDEE, you're guessing at how much to eat — and guessing rarely leads to consistent results whether your goal is fat loss, muscle building, or simply maintaining your current body composition.
The calculation starts with your Basal Metabolic Rate (BMR) — the calories your body burns just to stay alive at rest. BMR accounts for roughly 60–70% of your total daily calorie burn. Add the calories from physical activity and the thermic effect of food, and you get your TDEE.
✓Mifflin-St Jeor equation verified — Am J Clin Nutr 1990 & J Am Diet Assoc 2005 — April 2026
What Is BMR and Why Does It Matter?
Your Basal Metabolic Rate is the energy your body expends in a state of complete rest — the minimum number of calories required to keep your heart beating, lungs breathing, kidneys filtering, and cells functioning. BMR is determined primarily by your body size (weight and height), age, and biological sex. Larger bodies, younger people, and males generally have higher BMRs.
BMR is important because it sets the floor for your calorie intake. Eating consistently below your BMR forces your body into a state of extreme caloric restriction, leading to muscle loss, hormonal disruption, reduced metabolic rate, and nutritional deficiencies. Even when losing weight aggressively, your calorie intake should remain above BMR — ideally no lower than 1,200 kcal/day for women or 1,500 kcal/day for men.
TDEE Activity Multiplier Reference Table
After calculating BMR, multiply by the appropriate activity factor to get your TDEE. Most people underestimate their activity level. If you're unsure, choose the lower option — it's easier to add calories than explain why you're not losing weight on a "moderate" calorie deficit.
Activity Level
Multiplier
Description
Example
Sedentary
×1.2
Little or no exercise
Desk job, no gym
Lightly Active
×1.375
Light exercise 1–3 days/week
Occasional walks, yoga 2×/week
Moderately Active
×1.55
Moderate exercise 3–5 days/week
Gym 4×/week, average pace
Very Active
×1.725
Hard exercise 6–7 days/week
Daily gym sessions, sports
Extra Active
×1.9
Physical job + hard daily exercise
Construction worker who trains daily, pro athletes
How to Use Your TDEE for Weight Loss, Maintenance, and Muscle Gain
Once you know your TDEE, you have a precise baseline for every nutrition goal:
Weight loss: Create a calorie deficit of 300–500 calories below TDEE. A 500 kcal/day deficit produces approximately 1 lb of fat loss per week (since 3,500 kcal = ~1 lb of body fat). This is sustainable and preserves muscle mass.
Maintenance: Eat at TDEE. Track for 2–3 weeks and adjust by ±100–200 kcal if weight trends unexpectedly up or down.
Lean bulk (muscle gain): Eat 200–300 calories above TDEE. This "lean surplus" provides enough energy to support muscle protein synthesis without excessive fat gain. Larger surpluses build fat faster than muscle.
💡 Key Insight — TDEE Is an Estimate, Not a Law: The Mifflin-St Jeor equation predicts BMR within ±10% for most healthy adults. That means your calculated TDEE may be 150–300 calories off in either direction. Treat it as a starting point, not a fixed rule. Track your weight for 2–3 weeks, then adjust your calorie target by 100–200 kcal if results don't match the expected trend. Real-world tracking beats theoretical precision every time.
TDEE vs BMR: Key Differences and When to Use Each
BMR and TDEE are often confused. Here's the critical distinction: BMR is what you burn at rest. TDEE is what you burn living your actual life. You should almost never design a diet around BMR alone. The only context where BMR matters directly is setting an absolute floor — you should not eat below BMR long-term. For all practical dietary planning, use TDEE as your reference point.
⚠️ Common Mistake: 80% of people overestimate their activity level when calculating TDEE. If you work a desk job but exercise 4 times per week, you are likely "moderately active" at best — not "very active." Overestimating activity leads to a TDEE that is 200–400 calories too high, turning what you think is a deficit into maintenance or even a surplus. When in doubt, go one activity level lower than you think.
Frequently Asked Questions
TDEE stands for Total Daily Energy Expenditure — the total number of calories your body burns in a typical day including all activities. It is calculated by first estimating Basal Metabolic Rate (BMR) using the Mifflin-St Jeor equation, then multiplying by an activity factor between 1.2 (sedentary) and 1.9 (extremely active). TDEE = BMR × Activity Multiplier.
The Mifflin-St Jeor equation is the most widely recommended formula for estimating BMR. For men: BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) + 5. For women: BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) − 161. Published in the American Journal of Clinical Nutrition in 1990, it is validated to predict BMR within 10% of measured values for most healthy adults.
BMR (Basal Metabolic Rate) is the calories your body burns at complete rest to maintain vital functions. TDEE (Total Daily Energy Expenditure) includes BMR plus calories burned through physical activity and digestion. TDEE is always higher than BMR and is the number used for setting calorie goals for weight loss, maintenance, or muscle gain.
Eat 300–500 calories below your TDEE to lose fat. A 500 kcal/day deficit produces approximately 1 lb of fat loss per week (3,500 kcal = ~1 lb body fat). Never eat below BMR long-term — minimum 1,200 kcal/day for women, 1,500 kcal/day for men. Larger deficits cause muscle loss and metabolic adaptation without proportionally faster fat loss.
Sedentary = ×1.2. Lightly active (exercise 1–3 days/week) = ×1.375. Moderately active (exercise 3–5 days/week) = ×1.55. Very active (hard exercise 6–7 days/week) = ×1.725. Extra active (physical job + daily training) = ×1.9. When unsure, choose one level lower — studies show 80% of people overestimate their activity level.
The Mifflin-St Jeor equation predicts resting metabolic rate within ±10% for most healthy adults. Activity multipliers add additional variability. Treat your calculated TDEE as a starting estimate. Track your weight for 2–3 weeks, then adjust calories by 100–200 if results don't match expectations. Individual metabolic variation means real results must guide refinement.
Yes. Eating consistently at your TDEE is the foundation of weight maintenance. Consistently eating above TDEE leads to weight gain; below TDEE leads to weight loss. Use your calculated TDEE as a starting point, track real-world results for 2–3 weeks, and adjust based on actual weight trends rather than theory alone.
For lean muscle building, eat 200–300 calories above your TDEE (a "lean bulk" surplus). This provides energy for muscle protein synthesis while limiting excess fat gain. Pair with adequate protein (1.6–2.2 g/kg bodyweight/day) and progressive resistance training. Eating too far above TDEE accelerates fat gain without proportionally increasing muscle growth.
Yes. As you lose weight, your BMR decreases because there is less body mass to maintain. TDEE also decreases proportionally. Recalculate your TDEE every 10–15 lbs of weight change to update your calorie target. Plateaus during weight loss often occur because TDEE has decreased but calorie intake hasn't been adjusted down to maintain the deficit.
Common reasons: underestimating calorie intake (not weighing food), overestimating activity level (use a lower multiplier), water retention masking fat loss (normal 2–5 lb fluctuations), metabolic adaptation from prolonged restriction, medical conditions (thyroid, PCOS), or medications. Track accurately for 3 weeks before adjusting. Weight loss is not linear — weekly averages matter more than daily numbers.
Never eat below your BMR long-term. General minimums: 1,200 kcal/day for women, 1,500 kcal/day for men. Very low calorie diets slow metabolism, cause muscle loss, disrupt hormones, and create nutritional deficiencies. A sustainable deficit is 300–500 calories below TDEE. If TDEE is very low, consult a registered dietitian for personalized guidance.
Yes. TDEE decreases with age primarily because BMR declines as lean muscle mass decreases. After age 30, BMR drops approximately 1–2% per decade. A 50-year-old and a 30-year-old with identical stats and activity will have different TDEEs. Strength training is the most effective intervention to slow BMR decline with age by preserving muscle mass.