Use this Harris Benedict Calculator to estimate your basal metabolic rate (BMR) and total daily energy expenditure (TDEE). Enter your sex, age, height, weight, and activity level to calculate estimated resting calories and activity-adjusted daily calorie needs.

The calculator uses the original Harris–Benedict BMR equation, then multiplies the BMR estimate by an activity factor to estimate maintenance calories. This can be useful as a starting point for general adult calorie planning, maintenance tracking, fat-loss planning, weight-gain planning, and comparing how activity level changes daily energy needs.

Important note: This calculator gives an estimate only. It is not a medical test, metabolic diagnosis, nutrition prescription, weight-loss plan, weight-gain plan, or eating disorder treatment tool. If you are under 18, pregnant, breastfeeding, underweight, losing weight unintentionally, recovering from illness, managing diabetes, kidney disease, thyroid disease, heart disease, digestive conditions, chronic illness, or have an eating disorder history, consult a qualified healthcare professional or registered dietitian before relying on calculator-based calorie targets.

What This Harris Benedict Calculator Calculates

This calculator estimates BMR and TDEE from basic body measurements and activity level.

Input or Result	What It Means	Use Note
Sex	Selects the Harris–Benedict equation constants.	Male and female formulas use different coefficients.
Age	Your age in full years.	The BMR estimate decreases as age increases in the formula.
Height	Your body height.	Converted to centimeters before calculation if needed.
Weight	Your body weight.	Converted to kilograms before calculation if needed.
Activity level	The PAL or activity multiplier used to estimate TDEE.	Higher activity factors produce higher maintenance calorie estimates.
BMR	Estimated basal metabolic rate.	Resting calorie estimate before activity is added.
TDEE	Estimated total daily energy expenditure.	Activity-adjusted estimate of maintenance calories.
Step-by-step derivation	Shows how your numbers are placed into the equation.	Useful for checking the formula and understanding the result.

What BMR and TDEE Mean

BMR, or basal metabolic rate, estimates the calories your body uses at rest to support essential functions such as breathing, circulation, temperature regulation, cell maintenance, and organ function.

TDEE, or total daily energy expenditure, estimates your total calorie use across a full day after activity is included. TDEE is usually more practical for daily calorie planning because it includes resting energy use plus movement and exercise.

Term	Full Name	What It Means	Common Use
BMR	Basal metabolic rate	Estimated calories used at rest under controlled conditions.	Baseline resting calorie estimate.
RMR	Resting metabolic rate	Resting calorie use under less strict conditions than BMR.	Often used similarly to BMR in practical planning.
TDEE	Total daily energy expenditure	Total estimated daily calories after activity is included.	Maintenance calorie planning.
Maintenance calories	Calories needed to maintain body weight	Usually estimated from TDEE.	Starting point for weight-loss or weight-gain targets.

Original Harris–Benedict Equation

This calculator uses the original Harris–Benedict equation format for BMR.

Sex	Formula	Units Required
Male	BMR = 66.5 + (13.75 × weight in kg) + (5.003 × height in cm) − (6.755 × age in years)	Weight in kg, height in cm, age in years.
Female	BMR = 655.1 + (9.563 × weight in kg) + (1.850 × height in cm) − (4.676 × age in years)	Weight in kg, height in cm, age in years.

After estimating BMR, the calculator estimates TDEE with:

TDEE = BMR × activity factor

Formula Summary

Result or Variable	Formula or Meaning	Important Note
Male BMR	66.5 + 13.75W + 5.003H − 6.755A	W = kg, H = cm, A = age in years.
Female BMR	655.1 + 9.563W + 1.850H − 4.676A	W = kg, H = cm, A = age in years.
TDEE	BMR × activity factor	Activity-adjusted maintenance calorie estimate.
W	Body weight	Converted to kilograms if needed.
H	Height	Converted to centimeters if needed.
A	Age	Entered in full years.
Activity factor	PAL-style multiplier	Selected from the activity level dropdown.

Activity Multiplier Guide

The activity multiplier adjusts BMR upward to estimate daily calorie needs. Choose the level that best describes your average weekly routine, not only your hardest workout day.

Activity Level	Common Multiplier	Typical Description	Common Caution
Sedentary	1.2	Little or no structured exercise; mostly sitting.	May underestimate needs if daily steps or job movement are high.
Light	1.375	Light exercise or regular easy movement 1–3 times per week.	May not fit people with active jobs.
Moderate	1.55	Moderate exercise 3–5 times per week.	Workout intensity and total daily movement can vary widely.
Very active	1.725	Hard exercise 6–7 times per week or an active routine.	May still be too low or too high depending on training volume.
Extra active / physical job	1.9	Very hard training, physical work, or high daily movement.	Real needs should be checked against body-weight trends.
Professional athlete	2.3	Very high training volume and recovery demands.	Individual sports nutrition planning is usually better than a simple multiplier.

Activity level is one of the biggest sources of error in TDEE estimates. Two people with the same BMR can have very different daily calorie needs because of steps, standing time, job movement, workouts, training intensity, and recovery needs.

Height and Weight Unit Conversions

The Harris–Benedict equation uses height in centimeters and weight in kilograms. If you enter feet, inches, or pounds, the calculator converts them internally before applying the formula.

Conversion	Formula	Example
Pounds to kilograms	kg = lb × 0.45359237	180 lb ≈ 81.65 kg
Kilograms to pounds	lb = kg ÷ 0.45359237	80 kg ≈ 176.37 lb
Feet and inches to total inches	inches = feet × 12 + inches	5 ft 10 in = 70 in
Inches to centimeters	cm = inches × 2.54	70 in = 177.8 cm
Centimeters to inches	inches = cm ÷ 2.54	180 cm ≈ 70.87 in

How the Harris Benedict Calculator Works

Step	What Happens	Why It Matters
Step 1	You enter sex, age, height, and weight.	These values are required by the Harris–Benedict formula.
Step 2	The calculator normalizes height and weight.	Height is stored in cm and weight is stored in kg for the formula.
Step 3	The calculator estimates BMR.	This gives estimated resting calorie use.
Step 4	The calculator applies the selected activity factor.	This estimates TDEE or maintenance calories.
Step 5	The calculator shows a step-by-step derivation.	This helps you understand and verify the calculation.

How to Use This Harris Benedict Calculator

1. Select your sex as used by the calculator’s equation.
2. Enter your age in full years.
3. Select your average daily activity level.
4. Enter your height and choose the correct height unit.
5. Enter your weight and choose the correct weight unit.
6. Click Calculate.
7. Review your estimated BMR.
8. Review your estimated TDEE or maintenance calories.
9. Use the result as a starting estimate, then adjust based on real-world trends.

Worked Example: Male Harris–Benedict BMR

Suppose a 30-year-old male enters:

• Weight: 80 kg
• Height: 180 cm
• Age: 30 years

Step	Calculation	Result
Use male formula	BMR = 66.5 + 13.75W + 5.003H − 6.755A	Male Harris–Benedict equation.
Substitute values	BMR = 66.5 + 13.75 × 80 + 5.003 × 180 − 6.755 × 30	Inputs placed into formula.
Weight part	13.75 × 80	1100
Height part	5.003 × 180	900.54
Age part	6.755 × 30	202.65
Final BMR	66.5 + 1100 + 900.54 − 202.65	1864.39 kcal/day

Result: This person’s estimated BMR is about 1864 kcal/day.

Worked Example: Estimate TDEE from BMR

Now suppose the same person selects a moderate activity factor of 1.55.

Step	Calculation	Result
BMR from previous example	1864.39 kcal/day	Estimated resting calories.
Activity factor	1.55	Moderately active.
TDEE formula	TDEE = BMR × activity factor	Activity-adjusted calories.
Substitute values	1864.39 × 1.55	2889.8 kcal/day

Result: This person’s estimated maintenance intake is about 2890 calories/day.

Worked Example: Female Harris–Benedict Estimate

Suppose a 35-year-old female enters:

• Weight: 65 kg
• Height: 165 cm
• Age: 35 years
• Activity factor: 1.375

Step	Calculation	Result
Use female formula	BMR = 655.1 + 9.563W + 1.850H − 4.676A	Female Harris–Benedict equation.
Substitute values	BMR = 655.1 + 9.563 × 65 + 1.850 × 165 − 4.676 × 35	Inputs placed into formula.
Weight part	9.563 × 65	621.595
Height part	1.850 × 165	305.25
Age part	4.676 × 35	163.66
Estimate BMR	655.1 + 621.595 + 305.25 − 163.66	1418.29 kcal/day
Estimate TDEE	1418.29 × 1.375	About 1950 kcal/day

Result: The estimated BMR is about 1418 kcal/day, and the estimated maintenance intake is about 1950 calories/day.

Worked Example: Compare Activity Levels

Using the same BMR estimate of 1864.39 kcal/day, the estimated TDEE changes significantly based on activity level.

Activity Level	Multiplier	Estimated TDEE
Sedentary	1.2	2237 kcal/day
Lightly active	1.375	2564 kcal/day
Moderately active	1.55	2890 kcal/day
Very active	1.725	3216 kcal/day
Extra active	1.9	3542 kcal/day
Professional athlete	2.3	4288 kcal/day

This example shows why selecting a realistic activity level is important. Overestimating activity can make the TDEE result too high, while underestimating activity can make it too low.

How to Interpret the Result

The calculator gives estimated calorie needs, not a guaranteed exact value. The result is best treated as a starting point for planning.

Result	Meaning	How to Use It
BMR	Estimated resting calorie use.	Helps show your baseline energy estimate before activity is included.
TDEE	Estimated total daily calorie use.	Starting point for maintenance-calorie planning.
Activity factor	The multiplier used to estimate TDEE.	Check whether the selected activity level matches your real routine.
Higher TDEE	Usually reflects higher BMR, higher activity, or both.	May be appropriate for active users or larger bodies.
Lower TDEE	Usually reflects lower BMR, lower activity, or both.	May be appropriate for smaller or less active users.
Unexpected result	May come from unit selection, activity level, or formula assumptions.	Check inputs and compare against multi-week body-weight trends.

If your body weight rises over several weeks while eating around the displayed TDEE, your real maintenance calories may be lower than the estimate. If your body weight drops over several weeks, your real maintenance calories may be higher than the estimate.

How to Adjust the Estimate Over Time

Because the result is only an estimate, you may need to adjust it after observing your real-world trend.

Observed Trend	Possible Meaning	General Adjustment Idea
Weight stays mostly stable.	Intake may be near maintenance.	Continue monitoring if maintenance is the goal.
Weight slowly decreases.	Intake may be below maintenance.	Increase calories if maintaining or gaining is the goal.
Weight slowly increases.	Intake may be above maintenance.	Reduce calories if maintaining or losing is the goal.
Weight changes sharply in a few days.	May reflect water, glycogen, sodium, digestion, or tracking inconsistency.	Look at multi-week averages, not one-day changes.
Energy or training performance drops.	Calories, carbohydrates, recovery, or health status may need review.	Adjust carefully and consider professional guidance when needed.

Body weight naturally fluctuates. For most planning, a multi-week trend is more useful than a single weigh-in.

Why the Estimate May Differ From Real Calorie Needs

The Harris–Benedict equation estimates average energy needs based on a small set of inputs. Real calorie needs can differ because of factors the equation does not fully measure.

Factor	Why It Matters	Planning Note
Body composition	Muscle mass and fat mass can affect energy needs beyond weight alone.	People with the same weight may burn different calories.
Non-exercise activity	Steps, standing, fidgeting, chores, and job movement can vary widely.	Daily movement can change TDEE substantially.
Exercise intensity	The same activity label can represent very different training loads.	Use real progress to verify the estimate.
Metabolic adaptation	Dieting history and weight changes can influence energy expenditure.	Past weight loss or prolonged dieting may affect real needs.
Health conditions	Some medical conditions can affect weight, appetite, or metabolism.	Use professional guidance when symptoms or diagnoses are involved.
Medications	Some medications can affect appetite, fluid balance, or body weight.	Ask a healthcare professional if medication changes affect weight.
Tracking accuracy	Food labels, portions, wearable devices, and exercise estimates can be imprecise.	Use consistent tracking methods and trend data.

Harris Benedict vs Mifflin–St Jeor

The Harris–Benedict and Mifflin–St Jeor equations are both used to estimate resting calorie needs, but they are different formulas and can give different results for the same person.

Equation	What It Estimates	Common Use	Important Note
Harris–Benedict	BMR estimate from sex, age, height, and weight.	Traditional calorie-needs calculations.	Used by this calculator.
Mifflin–St Jeor	Resting calorie estimate from sex, age, height, and weight.	Common modern BMR/RMR calculator method.	May produce a different estimate.
Activity-adjusted version	TDEE estimate from BMR/RMR × activity factor.	Maintenance calorie planning.	The activity factor is often the largest source of difference.
Indirect calorimetry	Measured resting energy expenditure.	Clinical or laboratory measurement.	More individualized than prediction equations.

Different equations can give different estimates. That does not mean one calculator is automatically wrong; it means predictive equations should be treated as starting estimates.

Maintenance, Fat Loss, and Weight Gain

The TDEE result is usually interpreted as an estimated maintenance-calorie level. Weight-change targets are created by adjusting calories above or below maintenance.

Goal	Calorie Relationship	Expected Trend Over Time	Important Note
Maintain weight	Calories near estimated TDEE.	Weight stays relatively stable.	Use multi-week trends to confirm.
Lose weight	Calories below estimated TDEE.	Weight tends to decrease over time.	A safe deficit depends on health, body size, and context.
Gain weight	Calories above estimated TDEE.	Weight tends to increase over time.	Muscle gain also depends on training, protein, and recovery.
Improve performance	Calories may need to support training and recovery.	Performance, energy, and recovery should be monitored.	A sports dietitian or coach may be useful.

Calorie targets should still consider nutrition quality, protein, fiber, micronutrients, hunger, training performance, medical context, and sustainability.

Who Should Be Careful With Calorie Targets?

Some people should not rely on calculator-generated calorie targets without professional support.

Situation	Why Extra Care Is Needed
Children and teenagers	Growth and development require age-specific nutrition guidance.
Pregnancy or breastfeeding	Energy needs and weight targets are different and should be individualized.
Current or past eating disorder	Calorie targets may require specialized clinical support.
Diabetes or blood-sugar management	Calorie and carbohydrate changes may affect glucose management.
Kidney, liver, thyroid, heart, or gastrointestinal conditions	Medical nutrition needs can differ from calculator estimates.
Medication-managed conditions	Some medications affect appetite, weight, fluid balance, or metabolism.
Unexplained weight loss or rapid weight gain	Medical causes should be evaluated.
Competitive athletes	Training load, recovery, performance, and body composition goals require more detail.
Clinician-prescribed nutrition plan	Calculator estimates should not override individualized medical guidance.

When This Calculator Is Useful

Use Case	How the Calculator Helps
Estimating BMR	Calculates resting calorie needs from age, sex, height, and weight.
Estimating TDEE	Applies an activity factor to estimate maintenance calories.
Comparing activity levels	Shows how daily calorie needs change with different multipliers.
Planning a starting calorie target	Provides a baseline before adjusting for fat loss or weight gain.
Cross-checking food-tracking apps	Gives an independent estimate to compare with app targets.
Nutrition education	Explains the difference between BMR, RMR, TDEE, and maintenance calories.
Preparing questions for a professional	Helps users discuss calorie estimates with a doctor, dietitian, trainer, or coach.

When You May Need More Than This Calculator

A simple Harris Benedict Calculator may not be enough when medical, performance, or clinical nutrition needs are involved.

Situation	Why More Guidance May Be Needed
Medical weight-loss plans	Calorie targets may need clinical supervision and monitoring.
Eating disorder recovery	Specialized support is important for safety and treatment.
Pregnancy or breastfeeding nutrition	Energy needs depend on stage and individual health.
Diabetes or blood-sugar management	Meal planning may need medical or dietitian guidance.
Kidney disease, heart disease, thyroid disease, or chronic illness	Energy and nutrient needs may differ from general estimates.
Sports performance nutrition	Training volume, recovery, and competition goals require more detail.
Bodybuilding contest preparation	Calorie targets may need precise monitoring and professional oversight.
Very low calorie intake	Low-energy intake should be medically supervised when risk is present.
Rapid or unexplained weight change	Medical evaluation may be necessary.
Clinical nutrition or prescribed diets	Calculator outputs should not replace professional instructions.

Common Mistakes to Avoid

Mistake	Why It Causes Problems
Choosing an activity level that is too high.	This can overestimate maintenance calories.
Choosing an activity level that is too low.	This can underestimate daily calorie needs.
Treating BMR as maintenance calories.	BMR is before activity is added.
Using one day of scale weight as proof.	Water, sodium, glycogen, and digestion can change weight quickly.
Assuming the equation is exact.	Harris–Benedict is predictive, not a direct metabolic measurement.
Ignoring food-tracking error.	Portion sizes, labels, oils, drinks, and snacks can be inaccurate or missed.
Cutting calories too aggressively.	Extreme restriction can increase health, hunger, and adherence risks.
Ignoring medical context.	Health conditions and medications can affect calorie needs.
Forgetting diet quality.	Calories matter, but protein, fiber, micronutrients, and food quality also matter.
Using adult formulas for children.	Children and teenagers have growth-related energy needs.

Important Assumptions and Limitations

• This calculator estimates BMR using the original Harris–Benedict equation.
• It applies a broad activity multiplier to estimate TDEE.
• The result is an estimate, not a measured metabolic rate.
• Activity multipliers may not match your actual daily energy expenditure.
• The calculator is intended for general adult planning, not pediatric nutrition.
• The calculator does not diagnose metabolic conditions, obesity, malnutrition, or eating disorders.
• It does not account for pregnancy, breastfeeding, chronic illness, medications, athletic periodization, injury recovery, or clinical nutrition needs.
• It does not account for exact body composition, metabolic adaptation, step count, job movement, food tracking error, or wearable-device error.
• It does not determine a safe calorie deficit or calorie surplus for every user.
• It does not replace individualized guidance from a doctor, registered dietitian, or qualified healthcare professional.

Practical Uses of a Harris Benedict Calculator

• Estimate BMR from age, sex, height, and weight.
• Estimate TDEE from BMR and activity level.
• Find a starting point for maintenance calories.
• Compare how activity level changes daily calorie needs.
• Plan a starting point for fat loss or weight gain.
• Cross-check daily calorie targets in food-tracking apps.
• Understand how body size and age affect calorie estimates.
• Compare Harris–Benedict with Mifflin–St Jeor estimates.
• Review whether selected calorie targets match real weight trends.
• Discuss nutrition goals with a clinician, dietitian, trainer, or coach.

Frequently Asked Questions

What is the Harris Benedict equation?

The Harris–Benedict equation is a predictive formula used to estimate basal metabolic rate from sex, age, height, and weight.

What does this Harris Benedict Calculator estimate?

It estimates BMR and then multiplies that estimate by an activity factor to calculate estimated TDEE or maintenance calories.

What is BMR?

BMR means basal metabolic rate. It estimates the calories your body uses at rest for basic functions such as breathing, circulation, temperature regulation, and organ function.

What is TDEE?

TDEE means total daily energy expenditure. It estimates your total daily calorie use after activity, movement, and exercise are included.

Is BMR the same as maintenance calories?

No. BMR is resting calorie use. Maintenance calories usually refer to TDEE, which includes activity and daily movement.

How is TDEE calculated from BMR?

TDEE is estimated by multiplying BMR by an activity factor. The formula is TDEE = BMR × activity factor.

Which activity level should I choose?

Choose the activity level that best reflects your average weekly routine, including daily movement, job activity, and exercise. Do not choose only based on your hardest workout day.

How accurate is the Harris Benedict Calculator?

It gives a starting estimate, not an exact measurement. Real calorie needs can differ because of body composition, activity, health, medications, tracking accuracy, and individual metabolism.

Why is my Harris Benedict result different from Mifflin–St Jeor?

Different equations use different coefficients and assumptions. It is normal for Harris–Benedict and Mifflin–St Jeor estimates to differ.

Can I use this calculator for weight loss?

You can use the TDEE result as a planning starting point, but calorie deficits should be chosen carefully. Medical conditions, eating disorder history, pregnancy, breastfeeding, and other health factors require professional guidance.

Can I use this calculator for weight gain?

You can use the TDEE result as a starting point for a calorie surplus, but weight gain quality depends on resistance training, protein intake, sleep, recovery, and individual response.

Should I follow the result exactly?

No. Treat the result as an estimate. Monitor multi-week body-weight trends, energy, hunger, training performance, and health context, then adjust carefully when needed.

Does TDEE include exercise?

Yes. TDEE is intended to estimate total daily calories after activity is included. The accuracy depends heavily on whether the selected activity level matches your real routine.

Can this calculator measure my metabolism?

No. It predicts calorie needs from a formula. Measuring resting energy expenditure usually requires clinical or laboratory testing such as indirect calorimetry.

Can this calculator replace a dietitian or doctor?

No. It provides educational estimates only. A healthcare professional or registered dietitian can account for health conditions, medications, symptoms, goals, lab results, and individual needs.

Report an Issue

If you notice an incorrect result, unclear explanation, broken input field, or formatting problem with this Harris Benedict Calculator, please contact us through the Contact Us page. Include the sex, age, activity level, height, height unit, weight, weight unit, and result shown so our editorial team can review the issue.

References

1. Cornell University — Basal Energy Expenditure: Harris–Benedict Equation
2. StatPearls / NCBI Bookshelf — Total Daily Energy Expenditure
3. Endotext / NCBI Bookshelf — Energy Expenditure and Estimating Resting Metabolic Rate
4. National Academies / NCBI Bookshelf — Dietary Reference Intakes for Energy
5. Mifflin et al. — A New Predictive Equation for Resting Energy Expenditure in Healthy Individuals
6. CDC — About Body Mass Index

Related Calculators

• Maintenance Calorie Calculator
• BMR Calculator (Mifflin–St Jeor)
• Calorie Calculator
• Calorie Deficit Calculator
• Weight Gain Calculator
• BMI Calculator
• Protein Calculator
• Macro Calculator
• Calories Burned Calculator

Harris Benedict Calculator Disclaimer

This Harris Benedict Calculator provides educational estimates of basal metabolic rate (BMR) and total daily energy expenditure (TDEE) using the original Harris–Benedict equation and an activity multiplier. Results depend on the sex, age, height, weight, activity level, unit selections, formula assumptions, and rounding choices entered by the user.

Activity multipliers are broad estimates and may not accurately reflect your real daily movement, job demands, exercise intensity, step count, muscle mass, metabolic adaptation, medical history, medication effects, illness, pregnancy, breastfeeding, or recovery needs. The result is a planning starting point, not a measured metabolic rate or personalized nutrition prescription.

This calculator is intended for general adult calorie planning only. It should not replace advice from a doctor, registered dietitian, or qualified healthcare professional, especially for users under 18, pregnancy, breastfeeding, eating disorders, diabetes, kidney disease, thyroid disease, chronic illness, medication-managed conditions, athletic performance nutrition, unexplained weight change, or medically supervised weight management.