.rmr-calculator-container {
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
max-width: 800px;
margin: 20px auto;
padding: 0;
border: 1px solid #e0e0e0;
border-radius: 8px;
background-color: #ffffff;
box-shadow: 0 4px 6px rgba(0,0,0,0.05);
}
.rmr-calc-header {
background-color: #2c3e50;
color: white;
padding: 20px;
border-top-left-radius: 8px;
border-top-right-radius: 8px;
text-align: center;
}
.rmr-calc-header h2 {
margin: 0;
font-size: 1.5rem;
}
.rmr-calc-body {
padding: 30px;
}
.rmr-form-group {
margin-bottom: 20px;
}
.rmr-form-group label {
display: block;
font-weight: 600;
margin-bottom: 8px;
color: #333;
}
.rmr-input-row {
display: flex;
gap: 15px;
flex-wrap: wrap;
}
.rmr-col-half {
flex: 1;
min-width: 200px;
}
.rmr-input-field {
width: 100%;
padding: 12px;
border: 1px solid #ddd;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box;
}
.rmr-radio-group {
display: flex;
gap: 20px;
margin-bottom: 15px;
}
.rmr-radio-label {
font-weight: normal !important;
cursor: pointer;
display: flex;
align-items: center;
gap: 5px;
}
.rmr-btn {
width: 100%;
background-color: #27ae60;
color: white;
border: none;
padding: 15px;
font-size: 18px;
font-weight: bold;
border-radius: 4px;
cursor: pointer;
transition: background-color 0.2s;
}
.rmr-btn:hover {
background-color: #219150;
}
.rmr-result-box {
margin-top: 30px;
background-color: #f8f9fa;
border: 1px solid #e9ecef;
border-radius: 8px;
padding: 20px;
text-align: center;
display: none;
}
.rmr-result-value {
font-size: 2.5rem;
color: #2c3e50;
font-weight: 800;
margin: 10px 0;
}
.rmr-result-label {
font-size: 1rem;
color: #666;
text-transform: uppercase;
letter-spacing: 1px;
}
.rmr-article {
max-width: 800px;
margin: 40px auto;
padding: 20px;
font-family: inherit;
line-height: 1.6;
color: #333;
}
.rmr-article h2 {
color: #2c3e50;
border-bottom: 2px solid #27ae60;
padding-bottom: 10px;
margin-top: 40px;
}
.rmr-article h3 {
color: #2c3e50;
margin-top: 30px;
}
.rmr-article p {
margin-bottom: 15px;
}
.rmr-article ul {
margin-bottom: 20px;
padding-left: 20px;
}
.rmr-article li {
margin-bottom: 10px;
}
/* Utility classes for toggling Metric/Imperial */
.imperial-inputs, .metric-inputs {
display: none;
}
.active-unit {
display: block;
}
function toggleRMRUnits() {
var radios = document.getElementsByName('unitSystem');
var selected = 'imperial';
for (var i = 0; i < radios.length; i++) {
if (radios[i].checked) {
selected = radios[i].value;
break;
}
}
var impDiv = document.getElementById('imperialInputs');
var metDiv = document.getElementById('metricInputs');
if (selected === 'imperial') {
impDiv.style.display = 'block';
metDiv.style.display = 'none';
} else {
impDiv.style.display = 'none';
metDiv.style.display = 'block';
}
}
function calculateRMR() {
// Inputs
var gender = document.getElementById('rmrGender').value;
var age = parseFloat(document.getElementById('rmrAge').value);
var weightKg = 0;
var heightCm = 0;
// Determine Unit System
var radios = document.getElementsByName('unitSystem');
var unit = 'imperial';
for (var i = 0; i < radios.length; i++) {
if (radios[i].checked) {
unit = radios[i].value;
break;
}
}
// Get Weight/Height and Convert if necessary
if (unit === 'imperial') {
var weightLbs = parseFloat(document.getElementById('rmrWeightLbs').value);
var heightFt = parseFloat(document.getElementById('rmrHeightFt').value);
var heightIn = parseFloat(document.getElementById('rmrHeightIn').value);
if (isNaN(weightLbs) || isNaN(heightFt) || isNaN(heightIn) || isNaN(age)) {
alert("Please enter valid numbers for all fields.");
return;
}
// Conversions: 1 lb = 0.453592 kg, 1 ft = 30.48 cm, 1 in = 2.54 cm
weightKg = weightLbs * 0.453592;
heightCm = (heightFt * 30.48) + (heightIn * 2.54);
} else {
var wKg = parseFloat(document.getElementById('rmrWeightKg').value);
var hCm = parseFloat(document.getElementById('rmrHeightCm').value);
if (isNaN(wKg) || isNaN(hCm) || isNaN(age)) {
alert("Please enter valid numbers for all fields.");
return;
}
weightKg = wKg;
heightCm = hCm;
}
// Mifflin-St Jeor Equation
// Men: (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5
// Women: (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161
var rmr = 0;
if (gender === 'male') {
rmr = (10 * weightKg) + (6.25 * heightCm) – (5 * age) + 5;
} else {
rmr = (10 * weightKg) + (6.25 * heightCm) – (5 * age) – 161;
}
// Round the result
rmr = Math.round(rmr);
// Display
var resultBox = document.getElementById('rmrResult');
var resultVal = document.getElementById('rmrValue');
resultVal.innerHTML = rmr.toLocaleString();
resultBox.style.display = 'block';
}
Understanding Your Resting Metabolic Rate (RMR)
When embarking on a health or fitness journey, understanding your caloric needs is a fundamental step. The "What Is My Resting Metabolic Rate Calculator" above is designed to estimate the number of calories your body requires to perform basic life-sustaining functions while at rest.
What is RMR?
Resting Metabolic Rate (RMR) represents the energy expenditure of your body when you are not performing any physical activities. Even when you are sleeping or sitting quietly on the couch, your body is hard at work breathing, circulating blood, controlling body temperature, and growing or repairing cells.
RMR accounts for approximately 60% to 75% of the total calories you burn in a day. Knowing this number provides a baseline for structuring a diet plan, whether your goal is weight loss, muscle gain, or maintenance.
RMR vs. BMR: What's the Difference?
You may often hear RMR used interchangeably with BMR (Basal Metabolic Rate), but there is a subtle scientific difference:
- Basal Metabolic Rate (BMR): The absolute minimum number of calories needed for basic functions in a dark room after 8 hours of sleep and a 12-hour fast. It is a theoretical minimum.
- Resting Metabolic Rate (RMR): A slightly more practical measurement taken under less strict conditions (e.g., sitting at rest during the day, not necessarily fasted). RMR is typically about 10% higher than BMR due to the energy cost of digestion and subtle movements.
For most practical nutrition planning, RMR is the more useful and realistic metric to use.
How is RMR Calculated?
Our calculator uses the Mifflin-St Jeor Equation, which is widely considered by the Academy of Nutrition and Dietetics to be the most accurate predictive equation for estimating RMR in healthy individuals.
The formula varies by gender:
- Men: (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5
- Women: (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161
Factors That Influence Your RMR
Several variables can cause your metabolic rate to vary:
- Muscle Mass: Muscle tissue burns more calories at rest than fat tissue. This is why resistance training often leads to a higher RMR over time.
- Age: As we age, metabolic rate tends to decrease, largely due to a loss of muscle mass and hormonal changes.
- Body Size: Larger individuals have more mass to support and generally have a higher RMR.
- Genetics: Some people naturally have a faster or slower metabolism due to their genetic makeup.
How to Use This Number for Weight Loss
Your RMR is just the starting point. To determine your Total Daily Energy Expenditure (TDEE), you must account for your physical activity level. If you eat exactly your RMR in calories, you will likely lose weight because you are not accounting for the energy burned during movement, work, and exercise.
To maintain weight, most people need to consume their RMR multiplied by an activity factor (ranging from 1.2 for sedentary individuals to 1.9 for extremely active athletes). To lose weight, a common strategy is to create a caloric deficit from your TDEE, not necessarily to eat below your RMR.