Calculate Resting Calorie Rate

This calculator estimates your Resting Metabolic Rate (RMR), also often referred to as Basal Metabolic Rate (BMR). This is the amount of energy (in calories) your body needs to function while at complete rest during a 24-hour period.

Calculate Your RMR

Male Female

kg lbs

cm inches

(If using inches, enter total inches. E.g., 5ft 10in = 70 inches)

Your Estimated Resting Metabolic Rate:

Calories / Day

function calculateRMR() { var gender = document.getElementById("rmrGender").value; var age = parseFloat(document.getElementById("rmrAge").value); var weightInput = parseFloat(document.getElementById("rmrWeight").value); var weightUnit = document.getElementById("rmrWeightUnit").value; var heightInput = parseFloat(document.getElementById("rmrHeight").value); var heightUnit = document.getElementById("rmrHeightUnit").value; var resultContainer = document.getElementById("rmrResultContainer"); var resultValue = document.getElementById("rmrResultValue"); if (isNaN(age) || age <= 0 || isNaN(weightInput) || weightInput <= 0 || isNaN(heightInput) || heightInput <= 0) { resultValue.innerHTML = "Please enter valid positive numbers for age, weight, and height."; resultValue.style.color = "red"; resultValue.style.fontSize = "18px"; resultContainer.style.display = "block"; return; } var weightKg = weightInput; if (weightUnit === "lbs") { weightKg = weightInput * 0.453592; } var heightCm = heightInput; if (heightUnit === "inches") { heightCm = heightInput * 2.54; } var rmr = 0; // Mifflin-St Jeor Equation if (gender === "male") { rmr = (10 * weightKg) + (6.25 * heightCm) – (5 * age) + 5; } else { rmr = (10 * weightKg) + (6.25 * heightCm) – (5 * age) – 161; } resultValue.innerHTML = Math.round(rmr).toLocaleString(); resultValue.style.color = "#e74c3c"; resultValue.style.fontSize = "36px"; resultContainer.style.display = "block"; }

Understanding Your Resting Metabolic Rate (RMR)

Your Resting Metabolic Rate (RMR) is a foundational concept in understanding human metabolism and energy balance. It represents the minimum number of calories your body requires to perform basic life-sustaining functions such as breathing, circulating blood, controlling body temperature, cell growth, and brain and nerve function.

Think of it as the "cost of keeping the lights on" in your body. Even if you slept all day without moving a muscle, your body would still burn this base amount of energy.

How is RMR Calculated?

This calculator uses the Mifflin-St Jeor Equation, which is widely considered one of the most accurate formulas for estimating BMR/RMR in healthy individuals. The formula takes into account four primary factors that influence metabolism:

• Gender: Men typically have a higher RMR than women due to usually having more lean muscle mass.
• Weight: Heavier individuals generally have a higher RMR because they have more tissue to support.
• Height: Taller individuals often have a larger skin surface area and more bone structure, leading to a slightly higher BMR.
• Age: As aging occurs, metabolic rate generally decreases, primarily due to a loss of lean muscle tissue over time.

RMR vs. Total Daily Energy Expenditure (TDEE)

It is crucial to understand that your RMR is NOT your total daily calorie needs. RMR only accounts for roughly 60-75% of the calories you burn in a day.

To find the total calories you burn (your Total Daily Energy Expenditure or TDEE), you need to account for two other factors:

1. Physical Activity: Calories burned through exercise and non-exercise movement (like walking to the car or fidgeting).
2. Thermic Effect of Food (TEF): The energy your body uses to digest, absorb, and store food.

How to Use This Number

Knowing your RMR is the starting point for any weight management plan.

Example: Let's say a 35-year-old woman weighs 65kg and is 165cm tall. The calculator estimates her RMR is approximately 1,366 calories per day.

• Warning: It is generally recommended never to eat below your RMR without medical supervision. Eating consistently below this level can signal starvation mode to your body, potentially slowing down your metabolism and leading to nutrient deficiencies.
• For Weight Maintenance: To maintain weight, she would multiply her RMR by an activity factor (e.g., x1.55 for moderately active) to find her TDEE, and eat that amount.
• For Weight Loss: A safe calorie deficit is usually calculated from the TDEE, not the RMR.