TDEE Calculator for All Ages

This TDEE calculator estimates the number of calories you burn each day. It uses your age, height, weight, sex, and activity level. The calculation uses the energy equations from the National Academies' Dietary Reference Intakes for Energy (2023), which were derived from Doubly Labeled Water (DLW) studies. Unlike BMR-based equations such as Harris-Benedict and Mifflin-St Jeor, they were derived from energy expenditure measured in people going about their normal lives rather than in controlled lab settings.

This calculator works for all ages including children, toddlers and infants. Once you know your number, you can use it to set calorie targets for weight loss, weight gain, or maintenance. For a deeper breakdown of your calorie needs by macronutrient, try our Macro Calculator.

What Is Your TDEE?

TDEE stands for Total Daily Energy Expenditure. It represents the total number of calories your body uses in a 24-hour period. This includes every metabolic process and physical movement. Your TDEE is the sum of several components: your Basal Metabolic Rate (BMR), the thermic effect of food (energy used to digest what you eat), non-exercise activity thermogenesis (NEAT), and the calories you burn through deliberate exercise.

Your body needs energy to keep essential functions running. These include breathing, blood circulation, nervous system activity, temperature regulation, and the continuous creation and replacement of body tissues. This energy comes from breaking down the chemical bonds in food through oxidation. The three primary macronutrients that supply this energy are carbohydrates and protein (about 4 calories per gram each), and fat (about 9 calories per gram). You can calculate the right balance for your goals with our Macro Calculator.

When you eat the same number of calories as you burn, your weight stays the same. This is called energy balance. Eating more than your TDEE creates a positive energy balance, so most of the excess is stored as body fat. Eating fewer calories than your TDEE creates a negative energy balance. This prompts your body to use stored fat as fuel, leading to weight loss. To estimate how much weight you can realistically lose, try our Calorie Deficit Calculator.

Knowing your TDEE is essential for building a meal plan that matches your energy needs. Whether you aim to build muscle, enhance endurance, lose fat, or maintain your current physique, your TDEE provides a baseline for planning.

Who the Calculator Covers

Your TDEE is how many calories you burn in a day. To keep your weight the same, eat about that many. Growing children and teens need a little more, so their results include a small allowance for growth. This total, TDEE plus growth, is their Estimated Energy Requirement (EER).

The 2023 update replaced the 2005 Institute of Medicine equations and, unlike them, uses one set of equations for people of all weights, including those with overweight or obesity. This calculator applies them to:

Adults 19 and older with a BMI (Body Mass Index) of 18.5 or more.
Children and teens aged 3 to 18 at or above the 5th BMI percentile.
Infants and toddlers from birth through age 2 (under 36 months), using their sex, length, and weight.

TDEE Formula Comparison

Most TDEE calculators rely on one of several BMR equations, all developed using indirect calorimetry, which measures energy expenditure in controlled lab settings. The most common are Mifflin-St Jeor, widely considered the best general-purpose adult formula; Harris-Benedict, originally published in 1919 and revised in 1984; Katch-McArdle, which factors in body fat percentage and works best for lean individuals; and Cunningham, which uses lean body mass and is commonly used for athletes.

This calculator takes a distinct approach. It applies the National Academies' 2023 equations derived from Doubly Labeled Water (DLW) studies. The DLW method is considered the gold standard for measuring total energy expenditure. Rather than confining subjects to a lab, DLW studies monitor energy use as participants follow their typical routines over one to three weeks, making the equations more representative of real-world calorie expenditure. The 2023 equations were built from a larger and more diverse DLW database than the 2005 ones, and they span a broader age range, including infants, toddlers, children, and adults, while the equations above target only adults.

How Many Calories Do I Burn per Day?

The number of calories you burn in a day depends on your body size, age, sex, and how active you are. As a general reference, the Dietary Guidelines for Americans estimate that most adults need somewhere between 1,600 and 3,000 calories per day, with women typically at the lower end:

Sedentary adults (desk job, minimal exercise) typically burn 1,600–2,000 calories per day for women and 2,000–2,600 for men.
Moderately active adults (some exercise 3–5 days per week) typically burn 1,800–2,200 calories per day for women and 2,200–2,800 for men.
Very active adults (intense training or physically demanding job) can burn roughly 2,400–3,000+ calories per day for women and 3,000–3,500+ for men. The Dietary Guidelines' ranges stop at an "active" level, so these figures are rough estimates.

These ranges are broad because individual metabolism varies significantly. Factors like muscle mass, hormonal balance, sleep quality, and even ambient temperature all influence how much energy your body uses. That is why a personalized calculation using your specific measurements, like the one this TDEE calculator provides, is far more useful than a generic range.

If your goal is weight loss, a good starting point is to eat 200–500 fewer calories than your TDEE. As you lose weight, your TDEE will also go down, so recalculate it regularly to keep your calorie intake below it. For a more precise target based on your timeline and goals, use our Calorie Deficit Calculator or Daily Calories and Macros Planner.

TDEE vs BMR: What's the Difference?

Your Basal Metabolic Rate (BMR) is the number of calories your body needs just to stay alive at complete rest, powering your heart, lungs, brain, and other organs. For most people, BMR accounts for 60–70% of total daily calorie burn.

Your TDEE builds on top of BMR by adding the energy you spend on daily movement, structured exercise, and digesting food. In practice, TDEE is always higher than BMR, and it's the number you should use when planning your calorie intake for weight loss, gain, or maintenance.

For example, someone with a BMR of 1,500 calories might have a TDEE of 2,100–2,400 calories depending on their activity level. If they want to lose weight, they would eat below their TDEE (not their BMR), aiming for roughly 1,700–2,000 calories per day. Very large deficits, such as eating below your BMR for extended periods, are generally not recommended, as they can lead to muscle loss, fatigue, and metabolic slowdown.

Frequently Asked Questions about TDEE

What is the difference between BMR and TDEE?

BMR (Basal Metabolic Rate) is the number of calories your body needs to perform basic functions at rest. TDEE includes BMR plus calories burned through daily activities, exercise, and the digestion of food (Thermic Effect of Food).

How do I use my TDEE to lose or gain weight?

To lose weight, eat fewer calories than your TDEE; to gain weight, eat more; to maintain your weight, eat about the same. Rapid weight loss from a large calorie deficit is generally not recommended, as it can lead to muscle loss, nutritional deficiencies, and metabolic slowdown. A moderate deficit of 200–500 calories below your TDEE is safer and easier to stick with.

How accurate is the calculator, and how can I make it more accurate?

The calculator uses the National Academies' 2023 equations, which were built from doubly labeled water measurements and cover people of every weight, including those with overweight or obesity. It does not calculate for adults with a BMI under 18.5 or children below the 5th BMI percentile, as the report does not show that the equations hold for them. Individual metabolism, muscle mass, and other factors can still make your actual needs higher or lower. To fine-tune it, track your calorie intake and body weight for 1–2 weeks and adjust your intake based on the results. Your TDEE also changes as your weight, muscle mass, age, and activity level change, so recalculate it from time to time to keep your calorie targets accurate.

Can children use this calculator?

Yes. For infants and toddlers under 36 months, it estimates daily calorie needs from sex, age, length, and weight. For children and teens aged 3 to 18, it uses age-appropriate equations plus a small allowance for growth, and it works for those at or above the 5th BMI percentile. A child's calorie needs and any weight goals should be set with their pediatrician.

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References

The TEE equations used in this calculator are from the National Academies of Sciences, Engineering, and Medicine's Dietary Reference Intakes for Energy (2023), published by The National Academies Press, which updated the 2005 Institute of Medicine equations using a larger doubly labeled water database. View
Research by C. Henry, published in Public Health Nutrition (2005), reviewed basal metabolic rate measurement methods and developed updated prediction equations based on a large dataset of human studies. View
A review by K.R. Westerterp, published in the European Journal of Applied Physiology (2017), explained the doubly labelled water method for measuring energy expenditure, considered the gold standard for validating estimation equations. View
The American Academy of Pediatrics' first comprehensive clinical practice guideline for evaluating and treating children and adolescents with obesity, by S.E. Hampl and colleagues, was published in Pediatrics (2023). View