Resting Metabolic Rate Test Calculator

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Resting Metabolic Rate (RMR) Calculator

Calculate your baseline daily calorie needs using the Mifflin-St Jeor Equation.

Male Female
Your Estimated Resting Metabolic Rate:
0
Calories / day

Understanding Your Resting Metabolic Rate (RMR)

Resting Metabolic Rate (RMR) is the total number of calories your body burns while at rest. This includes fundamental physiological functions such as breathing, blood circulation, cell production, and brain activity. While often used interchangeably with Basal Metabolic Rate (BMR), RMR typically accounts for slight movements and digestion, making it a more realistic baseline for daily life.

How the RMR Test Calculation Works

This calculator utilizes the Mifflin-St Jeor Equation, which is currently considered the gold standard in clinical settings for estimating metabolic rate without the use of expensive indirect calorimetry equipment. The formulas used are:

  • Men: RMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5
  • Women: RMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161

Practical Example

Consider a 35-year-old male who weighs 85 kg and stands 180 cm tall. His calculation would look like this:

(10 × 85) + (6.25 × 180) – (5 × 35) + 5 = 850 + 1125 – 175 + 5 = 1,805 Calories/day

This means even if he stayed in bed all day, his body would require approximately 1,805 calories to maintain its current weight and vital functions.

Factors That Influence Your RMR

Several variables can shift your metabolic rate higher or lower than the calculated estimate:

  • Muscle Mass: Muscle is more metabolically active than fat. People with higher lean body mass generally have higher RMRs.
  • Genetics: Some individuals naturally have a "faster" metabolism due to genetic predispositions.
  • Hormonal Health: Thyroid function plays a massive role in regulating how quickly your body uses energy.
  • Environmental Temperature: Being in very cold or very hot environments forces the body to work harder to maintain core temperature, increasing calorie burn.
function calculateRMR() { var gender = document.getElementById("rmrGender").value; var weight = parseFloat(document.getElementById("rmrWeight").value); var height = parseFloat(document.getElementById("rmrHeight").value); var age = parseFloat(document.getElementById("rmrAge").value); var resultDiv = document.getElementById("rmrResultContainer"); var valueDisplay = document.getElementById("rmrValue"); var descDisplay = document.getElementById("rmrDescription"); if (!weight || !height || !age || weight <= 0 || height <= 0 || age <= 0) { alert("Please enter valid positive numbers for weight, height, and age."); return; } var rmr = 0; if (gender === "male") { rmr = (10 * weight) + (6.25 * height) – (5 * age) + 5; } else { rmr = (10 * weight) + (6.25 * height) – (5 * age) – 161; } var finalRMR = Math.round(rmr); valueDisplay.innerHTML = finalRMR.toLocaleString(); var category = ""; if (gender === "male") { if (finalRMR < 1500) category = "Your RMR is on the lower end, typical for smaller frames or older age."; else if (finalRMR < 2000) category = "Your RMR is in the average range for most adult men."; else category = "You have a high metabolic baseline, likely due to size or significant muscle mass."; } else { if (finalRMR < 1200) category = "Your RMR is on the lower end, typical for smaller frames or older age."; else if (finalRMR < 1700) category = "Your RMR is in the average range for most adult women."; else category = "You have a high metabolic baseline, likely due to size or significant muscle mass."; } descDisplay.innerHTML = category + " This represents your 'break-even' point for energy before adding any physical activity."; resultDiv.style.display = "block"; resultDiv.scrollIntoView({ behavior: 'smooth', block: 'nearest' }); }

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