TDEE Calculator for All Ages

What is Total Daily Energy Expenditure?

Total Daily Energy Expenditure (TDEE) is the number of calories your body burns in a full day from all sources combined: basal metabolism, digestion, non-exercise movement, and structured exercise. Eat at that total and body weight stays stable over weeks.

NIH nutrition references describe resting energy as the largest share of daily burn for most people, with activity and food processing adding the rest.

TDEE sits above resting metabolic rate (RMR) or basal metabolic rate (BMR) because even sedentary adults burn additional calories walking, standing, fidgeting, and processing food. Athletes and physically active workers can have TDEE values 50 to 100 percent higher than their resting rate depending on training volume. Someone who is completely bedridden is the usual exception.

Weight loss, gain, and recomposition plans start from daily expenditure. This calculator uses the Mifflin-St Jeor equation for resting energy and applies standard activity multipliers to estimate full daily burn.

TDEE is an estimate of energy flow, not a measurement of how many calories a person may safely eat. Pregnancy, lactation, growth, fever, recovery from surgery, and some medications change energy needs in ways this adult calculator does not model. A clinician may use indirect calorimetry or condition-specific equations when a wrong estimate would affect treatment.

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How the Mifflin-St Jeor equation works

The Mifflin-St Jeor equation (1990) predicts resting energy expenditure (REE) from weight, height, age, and sex. For men: REE = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5. For women: the same formula minus 161.

In the original validation study of 498 healthy adults, Mifflin-St Jeor predicted measured REE within 10% for more individuals than the older Harris-Benedict or Owen equations. Frankenfield and colleagues later reviewed individual-level data and reported that Mifflin-St Jeor placed more predictions within 10% of indirect calorimetry than Harris-Benedict, with smaller overall error.

The Academy of Nutrition and Dietetics Evidence Analysis Library gives a strong rating to Mifflin-St Jeor using actual body weight when measured resting metabolic rate is unavailable.

This calculator computes BMR with Mifflin-St Jeor, then multiplies by an activity factor. Sedentary (little or no exercise) uses 1.2; lightly active 1.375; moderately active 1.55; very active 1.725; extra active 1.9. Choose the level that matches your typical week.

Worked example: a 35-year-old man who weighs 80 kg and is 180 cm tall has an estimated resting expenditure of 10 × 80 + 6.25 × 180 − 5 × 35 + 5 = 1,755 kcal/day. Selecting moderate activity gives 1,755 × 1.55 = 2,720 kcal/day after rounding. The multiplier contributes more uncertainty than the arithmetic, so 2,720 should be treated as the center of a range.

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Components of daily energy expenditure

Basal or resting metabolism accounts for roughly 60 to 75% of TDEE in sedentary people and a smaller share in highly active individuals. It covers calories for breathing, circulation, brain function, cell repair, and thermoregulation.

The thermic effect of food (TEF) is energy spent digesting, absorbing, and storing nutrients, typically 8 to 10% of total intake. Protein has the highest TEF, then carbohydrates, then fat.

Non-exercise activity thermogenesis (NEAT) includes all movement outside formal workouts: typing, cooking, pacing, and fidgeting. NEAT varies enormously between individuals and can differ by hundreds of calories per day at the same body weight.

Exercise activity thermogenesis (EAT) covers structured workouts. Even daily gym sessions usually contribute a modest fraction of TDEE compared with resting metabolism and NEAT. Most TDEE estimates use activity multipliers instead of precise exercise logs.

These components interact. A hard training block may raise exercise expenditure while fatigue lowers spontaneous movement later in the day. Dieting can also reduce body mass, food intake, and NEAT at the same time. Adding a watch estimate to a TDEE value that already includes exercise counts part of the same activity twice.

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How to use your TDEE result

Start with the displayed maintenance value. Cut 10% to 20% for fat loss. Add about 5% to 10% for gain, paired with progressive resistance training. Percentage changes scale to body size better than one fixed calorie shift for every adult.

For the example TDEE of 2,720 kcal/day, a 15% deficit is 408 kcal, giving a starting intake near 2,310 kcal/day. A 7% surplus is 190 kcal, giving about 2,910 kcal/day. Keep the target unchanged for at least two full weeks unless hunger, dizziness, glucose control, or another clinical concern requires earlier review.

Seven days at 2,310 kcal equal 16,170 kcal. Count oils, drinks, sauces, and weekend meals; those omissions often exceed the 100 to 200 kcal adjustment used to refine an estimate.

A calculator cannot set a universal minimum intake. Small adults, large adults, athletes, and people with medical conditions have different nutrient and energy needs. Seek a registered dietitian or physician for rapid loss, a history of an eating disorder, pregnancy, lactation, diabetes medication, unexplained weight change, or symptoms of under-fueling.

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Accuracy and how to fine-tune your TDEE

Predictive equations estimate average expenditure for people with your demographics. Individual variation from genetics, thyroid function, medications, sleep, stress, and prior dieting history can shift actual needs by 10 to 20% or more.

The most useful field check is empirical tracking. Log intake for 14 to 28 days and weigh under consistent morning conditions. Compare seven-day average weights, not isolated readings. If mean intake is 2,400 kcal and weight remains stable across a sufficiently long window, observed TDEE is close to 2,400 kcal despite a calculator result of 2,700.

If body weight falls 0.25 kg per week while average intake is 2,400 kcal, the simple static estimate is 2,400 + (0.25 × 7,700 ÷ 7) = about 2,675 kcal/day. Use several weeks and revise in steps of 100 to 200 kcal. Water and tissue composition make one week unreliable.

Metabolic adaptation during prolonged restriction can lower expenditure beyond the change expected from a smaller body. Reduced food intake also lowers the thermic effect of food, and fatigue may reduce NEAT. A plateau should trigger an audit of intake, movement, sleep, medications, and the weight trend before another calorie cut.

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Choosing an activity level without double counting

Activity labels mix exercise and daily movement. A lifter who sits the rest of the week may fit light activity. A postal carrier who never enters a gym may fit very active because occupational walking dominates the week.

Use steps and training time as supporting evidence, not conversion rules. Record a normal week of steps, exercise duration, and job demands. Select the lower plausible category when two labels seem equally defensible, then let the weight trend correct the estimate. Changing categories can move the result by several hundred calories.

Do not add exercise calories to an intake target derived from an activity multiplier unless the workout is outside the routine represented by that multiplier. For an unusual endurance event, a separate fueling plan may be appropriate, but consumer wearable calorie values can carry substantial individual error.

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Population limits of TDEE equations

Mifflin-St Jeor was developed in 498 adults aged 19 to 78, including normal-weight and obese participants. That breadth does not establish equal accuracy in every racial or ethnic group, elite athletes, adults with very low body fat, or people with major fluid shifts. Validation reviews report useful average performance but wide individual errors.

The sex-specific constants reflect the groups used to derive the equation. They do not measure hormone concentrations, organ mass, or body composition. People using gender-affirming hormone therapy should treat either output as an uncertain starting point and validate it against intake and weight data with clinical support when needed.

Children need pediatric equations. Pregnancy and lactation add energy for tissue growth and milk production. Critical illness, burns, cancer treatment, thyroid disease, and severe malnutrition can alter expenditure enough that a general calculator is unsuitable for clinical feeding decisions.

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Measurement options and safety checks

Indirect calorimetry measures oxygen consumption and carbon dioxide production to estimate resting expenditure. Doubly labeled water measures free-living total expenditure over days but is mainly a research method. Neither turns future intake into a fixed prescription because activity and body weight continue to change.

Stop self-directed restriction and seek care for fainting, persistent dizziness, chest pain, loss of menstrual periods, repeated bingeing, severe fatigue, or rapid unexplained weight loss. A calculated deficit should not override symptoms or a treatment plan. People taking insulin, sulfonylureas, blood pressure drugs, or diuretics may need dose review as intake and weight change.

For ordinary planning, consistent home measurements beat false precision. Use the same scale, similar clothing, and morning weigh-ins after using the bathroom. Pair weight with waist measurements, training performance, hunger, and recovery. The calculator gives a hypothesis; repeated observations determine whether it fits.

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How it works

BMR via Mifflin-St Jeor (1990): men = 10×weight + 6.25×height − 5×age + 5; women = same − 161. TDEE = BMR × activity factor.

Frequently asked questions

• How accurate is the TDEE calculator?Mifflin-St Jeor estimates BMR within 10% for most adults. Track weight for 2 weeks and adjust calories by 100 to 200 if needed.
• TDEE vs BMR: what is the difference?BMR is calories burned at complete rest. TDEE includes all daily activity and exercise on top of BMR.

Related calculators

References

1. Mifflin et al.. A new predictive equation for resting energy expenditure in healthy individuals
2. Hall et al.. Quantification of the effect of energy imbalance on bodyweight
3. Frankenfield et al.. Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults
4. NIH/National Academies. Energy - Recommended Dietary Allowances
5. Levine et al.. Non-exercise activity thermogenesis
6. CDC. Losing Weight
7. USDA/HHS. Dietary Guidelines for Americans
8. Trexler et al.. Metabolic adaptation to weight loss
9. Academy of Nutrition and Dietetics. Academy of Nutrition and Dietetics: Assess Energy Needs
10. NHLBI. Aim for a Healthy Weight: Guide to Behavior Change
11. Shcherbina et al.. Accuracy in wrist-worn, sensor-based measurements of heart rate and energy expenditure
12. National Academies. Dietary Reference Intakes for Energy