BMR (Harris–Benedict) + TDEE Calculator

Estimate basal metabolic rate and daily calorie needs using the Harris–Benedict equation and an activity multiplier.

Inputs
Sex
Required for Harris–Benedict constants.
Height
Uses source-value unit switching to avoid drift.
Results
Basal metabolic rate (BMR)
Estimated kcal/day at rest
Total daily energy expenditure (TDEE)
Estimated maintenance kcal/day
Activity factor used
Selected PAL multiplier
Normalized height
Stored internally in centimeters
Normalized weight
Stored internally in kilograms
Equation used
Original Harris–Benedict constants
Quick summary
Enter your details and click Calculate.
Step-by-step derivation
Provide inputs to see the working with your numbers.
BMR is estimated with the original Harris–Benedict equation. TDEE is then estimated by multiplying BMR by your selected activity factor.
This calculator is for general education only and does not replace medical or nutrition advice.

Use this Harris Benedict Calculator to estimate basal metabolic rate (BMR) and activity-adjusted daily calorie needs (TDEE).

Harris–Benedict Method

The calculator uses the original Harris–Benedict equations:

Male: BMR = 66.5 + (13.75 × weight in kg) + (5.003 × height in cm) − (6.755 × age)

Female: BMR = 655.1 + (9.563 × weight in kg) + (1.850 × height in cm) − (4.676 × age)

Daily calorie needs are then estimated with:

TDEE = BMR × activity factor

Example

For a 30-year-old male weighing 80 kg and measuring 180 cm:

BMR = 66.5 + (13.75 × 80) + (5.003 × 180) − (6.755 × 30)

BMR ≈ 1,864 calories/day

Using a moderate activity factor of 1.55:

TDEE ≈ 1,864 × 1.55 = 2,890 calories/day

This gives an estimated maintenance intake of approximately 2,890 calories per day.

Important Limitations

The Harris–Benedict equation predicts energy needs from age, sex, height, and weight. It does not directly measure metabolism or body composition, so actual calorie needs can differ.

Use the result as a starting estimate and adjust according to real body-weight trends, activity, and health circumstances.

Source

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