TDEE Calculator for All Age Groups

Use this calculator to determine your Total Daily Energy Expenditure (TDEE) and Estimated Energy Requirement (EER). It's accurate for all age groups, including infants and toddlers. The calculator uses formulas developed by the Institute of Medicine of the National Academies and published in their Dietary Reference Intakes (DRI) report.

What is TDEE?

TDEE is your body's total daily expenditure of energy to power its essential body functions to keep you alive and perform physical activities.

Your body constantly burns calories to support its autonomic systems, such as breathing, the nervous system, circulation, body temperature regulation, and performing physical activities. Energy is also required to transport, synthesize and replace molecules that make up body tissue. The body releases chemical bonds in food through oxidization to get its energy.

Fat, protein, and carbohydrates are the macronutrients that provide you with energy from foods. Carbohydrates and protein release about 4 kcal of energy per gram through oxidation, whereas fat releases about 9.4 kcal per gram.

Your Body's Energy Expenditure Components

BMR (Basal Metabolic Rate)

Basal metabolic rate (BMR) is your body's energy expenditure rate when digestion of food and physical activity has minimal influence on your metabolism. It reflects the minimum energy needed to sustain metabolic processes that keep you alive. An accurate BMR measurement requires a specific setting, such as an overnight fast where the subject hasn't eaten for 12 to 14 hours, resting awake and motionless while lying on their back in a thermoneutral environment. To be more meaningful, BMR is usually extrapolated over 24 hours, referred to as basal energy expenditure (BEE), and expressed as kcal per day.

The tools needed to measure BMR are not always readily accessible. However, BMR and BEE can be estimated using prediction equations based on body parameters such as weight, height, gender, and age. BMR is related to body size and is most closely correlated with lean body mass, which is total body weight minus the weight of its fat mass. Studies show that lean body mass accounts for about 73 percent of your BMR, with fat mass accounting for only an additional 2 percent. Thus, lean body mass is the single best predictor of RMR.

TEF (Thermic Effect of Food)

TEF is the energy required to digest, absorb, transport, metabolize, and store ingested nutrients. It accounts for a percentage of the body's total energy expenditure and depends on the amount and composition of the consumed food. Fats require the least energy to be processed, carbs are next in line, and protein requires the most. Consuming an average mixture of macros will elicit an additional energy expenditure equivalent to about 10 percent of the energy content of the food consumed.

TEPA (Thermic Effect of Physical Activity)

The most variable component of TDEE is energy expenditure from physical activity. It varies significantly among individuals. The Thermic Effect of Physical Activity typically accounts for 15 to 30% of daily calorie burn. It can rise to as much as one-half or more in active individuals, heavy laborers, and athletes. TEPA includes the energy expended through structured exercises and non-exercise activity thermogenesis (NEAT). NEAT refers to the energy burned through typical daily living activities such as performing household tasks, walking to the bus, light activities while sitting, driving, shopping and fidgeting.

Weight Loss and Weight Gain

TDEE is the sum of basal energy expenditure (BEE), the expenditure due to food's thermic effect (TEF), and physical activity's thermic effect (TEPA). With infants and children, TDEE also includes energy expenditures due to new tissue growth.

Your body will maintain its current weight if the number of calories you consume equals the number of calories you expend (your TDEE). Consume more than your TDEE amount, and you will gain weight because the surplus calories get stored as fat in fat tissues. Consume less than the TDEE amount, and you will lose weight because your body will break down stored fat to get the extra energy it needs.

Calculating TDEE and EER

Many TDEE calculators are available that can estimate your TDEE. They typically calculate your BMR value from a BMR prediction formula and then multiply it by a factor corresponding to your level of physical activity to arrive at a TDEE value. BMR prediction equations often estimate an individual's BMR based on height, weight, gender, and age. The Harris-Benedict equation, the Mifflin St-Jeor equation, and the Katch-McArdle formula are some of the more popular ones.

This calculator instead uses the most recent predictive formulas developed by the Institute of Medicine of the National Academies. The formulas were derived from energy expenditure data obtained by Doubly Labelled Water (DWL) studies. DLW is a superior TDEE measurement method because it's applied to individuals under free-living conditions. It has become the gold standard methodology in determining TDEE. The method involves administering two stable isotopic forms of water to a subject and then measuring their disappearance rates from body fluid (urine or blood) over a 1 to 3-week period. The differences in their disappearance rate reflect the amount of carbon dioxide production. From the disappearance rate and with knowledge of the diet composition, TDEE can be accurately determined.

Direct measurement of TDEE by the DLW method represents a distinct advantage over previous TDEE evaluation methods. The development of the DRI formulas for predicting TDEE and EER was based on an analysis of TDEE measurements made on individuals obtained by the DLW method. Measurements were made on 767 adults ages 19 and over, 844 children ages 3 through 18, and 320 infants and children up to 2 years of age.

Dietary Reference Intakes define EER as the calorie intake required to maintain long-term good health. Overweight or obese individuals have a greater weight than what is consistent with long-term good health, so EER values are not intended for them. The EER prediction formulas apply to:

1. Adults with a BMI (Body Mass Index) from 18.5 to 25.
2. Children ages 3 through 18 within the 5th to 85th percentile for BMI.
3. Infants and very young children, 0 through 2 years of age, within the 3rd to 97th percentile for BMI.

Overweight individuals who desire to lose weight can refer to their TDEE value, estimated by this calculator using the DRI formulas, as a baseline in planning an appropriate weight loss goal. To achieve a desirable lower steady-state body weight, overweight individuals must intake fewer calories than their current TDEE. Consuming 200 fewer calories daily than their TDEE would be a good starting point. TDEE decreases with weight loss, so TDEE should be checked regularly throughout the weight loss journey to ensure calorie intakes remain below TDEE.

The calculator applies different DRI formulas depending on the subject's age, gender, and weight status. The formulas accept age in years, weight in kilograms (kg), and height in meters (m).

The following EER (Estimated Energy Requirements) formulas apply to subjects in a normal weight range, infants and toddlers.

The following TDEE (Total Daily Energy Expenditure) formulas apply to overweight subjects.

The PA (physical activity) categories are defined as follows:

• Sedentary: Typical daily living activities such as household tasks, walking to the bus, light activities while sitting, driving, shopping.
• Low Active: Typical daily living activities plus 30 to 60 minutes of moderate activities such as walking or cycling leisurely, golfing without a cart etc.
• Active: Typical daily living activities plus at least 60 minutes of daily moderate activity. cycling (leisurely), golf (without cart), swimming (slow), walking 3-4mph, etc.
• Very Active: Typical daily living activities plus at least 60 minutes of daily moderate activity plus an additional 60 minutes of vigorous activity or 120 minutes of moderate activity

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