BMR Calculator

Calculate your Basal Metabolic Rate (BMR) to discover the baseline calories your body burns at rest each day to sustain life.

Summary:A BMR calculator estimates the number of calories burned at complete rest to maintain vital organ function, serving as the foundational baseline for calculating total daily energy needs.

Body parameters

Calculated Energy Outputs

Basal Metabolic Rate (BMR)0 kcal/day
Active Burn (TDEE)0 kcal/day

Recommended Target Calorie Ranges

Weight Loss1200
Maintenance0
Weight Gain500

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How to Use BMR Calculator

Follow these steps to use the BMR Calculator: 1. Choose Metric (kg/cm) or Imperial (lbs/in) units. 2. Select Mifflin-St Jeor, Harris-Benedict, or Katch-McArdle formulas. 3. Input your weight, age, and activity multipliers. 4. Input body fat % to see LBM distribution and updated metabolic charts. Enter your measurements to calculate the estimate.

BMR Calculator Formula / How It Works

This calculator runs selected BMR formulas using weight, height, and age parameters. If body fat % is present in Katch mode, it derives LBM and uses it as the sole metabolic multiplier. TDEE is computed by applying activity multipliers (1.2 to 1.9).

Formula:Mifflin: Male BMR = 10w + 6.25h - 5a + 5, Female BMR = 10w + 6.25h - 5a - 161; Katch: BMR = 370 + 21.6 * LBM
Example Calculation:

For example, a 25-year-old male weighing 70kg at 175cm height has a BMR of approximately 1,630 kcal/day under Mifflin-St Jeor.

Frequently Asked Questions

BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest to maintain basic functions — breathing, circulation, cell production, and temperature regulation. This calculator estimates your BMR using either the Mifflin-St Jeor or Harris-Benedict equation.

BMR is the calories you burn doing nothing (at rest). TDEE (Total Daily Energy Expenditure) is BMR multiplied by your activity level — it represents the total calories you burn per day including exercise and movement. Multiply your BMR by an activity multiplier to get TDEE.

This calculator uses the Mifflin-St Jeor equation (published 1990), which is considered the most accurate for most adults: BMR = (10 × weight kg) + (6.25 × height cm) – (5 × age) + 5 (men) or –161 (women). It is within 10% of measured BMR for most people.

Multiply your BMR by an activity factor: 1.2 (sedentary), 1.375 (lightly active), 1.55 (moderately active), 1.725 (very active), or 1.9 (extremely active). The result is your TDEE — the calories needed to maintain your current weight. Eat less to lose weight; more to gain.

The Mifflin-St Jeor equation is accurate to within ±10% for most healthy adults. Accuracy decreases for very muscular individuals (tends to underestimate) or very obese individuals (tends to overestimate). For clinical accuracy, use indirect calorimetry measured by a healthcare professional.

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