Total Daily Energy Expenditure Estimate

Total daily energy expenditure describes energy used over a day. This calculator produces an illustrative estimate, rather than measuring that expenditure. It first estimates resting energy expenditure (REE) with the Mifflin–St Jeor equation, then multiplies it by a factor selected by you. Original resting-energy equation

The equation and the multiplier have different evidence status. The published equation was derived from a study of healthy adults; the five activity multipliers on this website are explicitly labeled site-selected model assumptions. They are not official exercise categories, verified measurements of your activity or prescriptions for what you should eat.

What Is TDEE and How Is It Calculated?

The calculator has two steps: estimate REE from weight, height, age and the sex term in the published equation; then calculate REE × selected factor. It does not separately measure resting metabolism, digestion, household movement or exercise. Its result card should therefore be read as a model output with stated assumptions.

The original study measured REE using indirect calorimetry in 498 healthy adults aged 19–78, including normal-weight adults and adults with obesity. It developed a prediction equation from those observations. It did not establish these website activity factors or a universal error margin for every person using an online calculator. Study abstract

For example, if estimated REE is 1,600 kcal/day and the selected factor is 1.55, multiplication gives 2,480 kcal/day. This is a worked arithmetic example, not a claim that a particular exercise schedule burns exactly 880 extra calories or that eating 2,480 kcal will maintain someone's weight.

The result is rounded to a whole kcal/day. That formatting does not make the underlying estimate accurate to one calorie. A source-based estimate and a direct measurement remain different even when their displays look equally precise.

How to Use This Calculator Accurately

Choose metric or imperial units before entering measurements. Metric inputs use kilograms and centimeters; imperial inputs use pounds and inches. Changing the unit setting clears weight and height so that a previous number is not silently interpreted in another unit. Enter height in inches as one number, not feet with a decimal: 5 feet 10 inches is 70 inches, not 5.10.

Enter a whole-number age from 19 through 78, the age range of the original study. The two sex options select the published equation's coefficients; they do not assess an individual's hormonal treatment, body composition or health circumstances. A formula choice is not a medical assessment. Equation population and terms

The activity selector offers these factors:

Every row is a calculation using the same hypothetical REE. These factors are not mapped to a validated number of exercise days, occupational duties or an athlete classification. Selecting a higher factor necessarily increases the output, but the form cannot confirm that your real expenditure increased by that amount.

If comparing two scenarios, keep a note of the factor and inputs used. A result without its assumption can be misleading: the same measurements produce several different outputs solely because the selected factor changed. Check the entries first when a result looks unexpected, rather than interpreting an input error as a metabolic finding.

The Mifflin-St Jeor Equation: Why This Formula

The simplified published equations are:

Male equation: REE = 10 × weight in kg + 6.25 × height in cm − 5 × age in years + 5.

Female equation: REE = 10 × weight in kg + 6.25 × height in cm − 5 × age in years − 161.

The male constant is positive five. The age term is subtracted in both equations. Keeping the signs and units correct matters more than presenting the answer with many decimal places. Mifflin and colleagues, original abstract

Why Mifflin over Harris-Benedict?

This page uses Mifflin–St Jeor so that its calculation can be traced to a specific published equation and study population. That choice does not establish that it is the best formula for every person or that its error disappears after multiplying by an activity factor. The website does not compare your result with measured expenditure.

Worked example: for the male equation with 80 kg, 180 cm and age 30, the terms are 800 + 1,125 − 150 + 5 = 1,780 kcal/day. At factor 1.55, the second step is 1,780 × 1.55 = 2,759 kcal/day. With the same measurements, the female equation gives 1,614 kcal/day for resting energy; multiplying by 1.55 gives 2,501.7, displayed as 2,502 kcal/day. These figures illustrate the code's arithmetic; they are not a diet plan for an 80 kg adult.

For imperial entries, the calculation converts pounds to kilograms and inches to centimeters before applying the same equation. Compare like units when checking your own calculation: inserting 180 inches into a formula expecting 180 centimeters produces a different number because the measurement itself is different.

Using Your TDEE for Weight Loss, Gain, and Maintenance

An expenditure estimate is useful for understanding the distinction between intake and expenditure, but it does not decide whether weight loss, gain or maintenance is appropriate for you. This tool assigns neither a calorie deficit nor a surplus and produces no goal date.

If comparing an intake value with an estimate, label both quantities. For example, an assumed expenditure of 2,400 kcal/day minus an entered intake of 2,100 kcal/day equals a 300 kcal/day numerical difference. If the expenditure is wrong, the difference is wrong even though subtraction is correct. The example does not recommend 2,100 kcal/day or establish that the person will lose a particular amount of weight.

Do not treat estimated REE or “BMR” as a universal minimum calorie intake or a dividing line between safe and unsafe eating. A resting-energy prediction does not test nutritional adequacy or select a personal dietary prescription. The current U.S. dietary guidelines state that calorie needs depend on age, sex, body size and activity; individual planning must also account for the person's circumstances. Dietary Guidelines 2025–2030, appropriate amount for you

The Macro Calculator converts a calorie total and percentages chosen by the user into grams. The Calorie Deficit Calculator subtracts two user-entered values. Neither makes this TDEE estimate an independently confirmed intake target.

NIDDK offers a separate Body Weight Planner based on a dynamic model, with a different purpose and specified exclusions. Its model is not implemented on this page. Do not transfer claims about that planner's research or features to this simpler multiplication tool. NIDDK planner information

Why Your TDEE Calculator Result Is Just a Starting Point

There are several distinct sources of uncertainty: the entered measurements, the resting-energy prediction, and the selected activity assumption. The calculator checks numerical input rules; it cannot check whether the measurements describe you correctly or whether the multiplier represents your daily activities.

A useful sensitivity check is to change only one assumption. With a hypothetical REE of 1,780 kcal/day, factors 1.375 and 1.55 produce approximately 2,448 and 2,759 kcal/day. The 311 kcal difference is created by the model choice. It is not proof that your real daily needs fall between those figures or that the endpoints form a confidence interval.

Recording food intake and weight may provide information for a care discussion, but a two-week period with nearly unchanged weight does not certify this formula's accuracy. This page provides no validated rule that a difference within 0.2 kg confirms maintenance calories, nor a mandatory instruction to adjust intake by 100–200 kcal.

NIDDK's dynamic-model research accounts for changes over time in energy expenditure and body composition. A fixed calorie difference therefore should not be turned into a guaranteed straight-line weight trajectory. Research behind the NIDDK planner

Keep scenario records separate from observations. “The tool estimated 2,759 kcal using factor 1.55” accurately describes a calculation. “My measured expenditure is 2,759 kcal” would require a measurement this page has not performed. This distinction matters when comparing results with a nutrition professional or another tool.

When to Work with a Professional Instead

Use an appropriate clinical or nutrition service when you need a personal intake plan, interpretation of unexpected weight change, or advice about a medical condition. The form has no fields for diagnosis, medication, pregnancy, lactation or eating-disorder history, and cannot incorporate those circumstances by inference.

NIDDK explicitly limits its Body Weight Planner to adults aged 18 and older and excludes pregnancy and breastfeeding. Those exclusions illustrate why a general adult energy tool should not be repurposed into pregnancy or lactation advice. This site's narrower 19–78 input range follows its own source equation; it does not establish suitability for every adult within those ages. NIDDK scope

If you already have a care plan, keep the prescribed targets and the online estimate clearly labeled rather than replacing one with the other. Ask what the estimate is intended to help with, which assumptions are relevant, and whether a direct measurement or different method is needed.

The original study's use of indirect calorimetry does not mean this website performs that procedure. It also does not justify a promise that a clinical measurement removes all uncertainty. Discuss the purpose and limitations of any measurement with the service performing it.

Frequently Asked Questions

What is a normal TDEE?

This page does not assign a universal normal range. It produces an estimate from the measurements and multiplier selected. Age, sex, body size and activity matter to energy needs, but an online output does not determine a personal target. U.S. dietary guidance

How accurate are TDEE calculators?

This tool has no universal ±10–15% accuracy guarantee. It combines a published resting-energy equation with an unvalidated site activity assumption. Correct arithmetic does not verify the result against your measured expenditure. Original equation

How often should I recalculate?

Recalculate when you want to compare a changed input or assumption. No evidence-based four- or six-week schedule is claimed for this website. A calculation is separate from the follow-up schedule in a personal care plan.

Does TDEE change with age?

The published equation contains an age term: holding its other inputs fixed, increasing age by one year decreases estimated REE by 5 kcal/day. This is a property of the model, not a measured annual change in an individual. Equation

What's the difference between TDEE and BMR?

TDEE refers to total daily expenditure; resting energy is only the first step in this site's model. This calculator specifically estimates REE and multiplies it by a factor. It does not measure BMR under standardized basal conditions or determine an intake floor.

Our TDEE guide is a separate article. When reading a related article, keep its stated method and sources distinct from the particular calculation described here.

Sources & Medical References

1. Mifflin MD and colleagues: original resting-energy equation, 1990 — formula, units, population and measurement method.
2. NIDDK: About the Body Weight Planner — the separate planner's purpose and population exclusions.
3. NIDDK: research behind its dynamic Body Weight Planner — why modeled weight change is not simple fixed-rate subtraction.
4. U.S. Dietary Guidelines for Americans 2025–2030 — calorie requirements depend on age, sex, body size and activity.

The five activity factors and the worked scenarios above are labeled website assumptions or derived arithmetic, not recommendations attributed to these authorities.