.rmr-calculator-container {
font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
max-width: 600px;
margin: 20px auto;
padding: 25px;
background-color: #f9fbfd;
border: 1px solid #e1e4e8;
border-radius: 8px;
box-shadow: 0 4px 6px rgba(0,0,0,0.05);
}
.rmr-calculator-container h3 {
text-align: center;
color: #2c3e50;
margin-top: 0;
}
.rmr-form-group {
margin-bottom: 15px;
}
.rmr-form-group label {
display: block;
margin-bottom: 5px;
font-weight: 600;
color: #34495e;
}
.rmr-input-row {
display: flex;
gap: 10px;
}
.rmr-form-control {
width: 100%;
padding: 10px;
border: 1px solid #ced4da;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box;
}
.rmr-radio-group {
display: flex;
gap: 20px;
margin-bottom: 15px;
justify-content: center;
}
.rmr-radio-label {
font-weight: normal;
cursor: pointer;
}
.rmr-btn {
width: 100%;
padding: 12px;
background-color: #3498db;
color: white;
border: none;
border-radius: 4px;
font-size: 18px;
font-weight: bold;
cursor: pointer;
transition: background-color 0.3s;
}
.rmr-btn:hover {
background-color: #2980b9;
}
.rmr-result {
margin-top: 25px;
padding: 20px;
background-color: #ffffff;
border-left: 5px solid #2ecc71;
border-radius: 4px;
display: none;
box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}
.rmr-result h4 {
margin: 0 0 10px 0;
color: #2c3e50;
}
.rmr-value {
font-size: 28px;
font-weight: bold;
color: #27ae60;
}
.rmr-subtext {
font-size: 14px;
color: #7f8c8d;
margin-top: 5px;
}
.unit-toggle {
display: flex;
justify-content: center;
margin-bottom: 20px;
background: #e9ecef;
padding: 5px;
border-radius: 20px;
width: fit-content;
margin-left: auto;
margin-right: auto;
}
.unit-btn {
padding: 8px 20px;
border: none;
background: transparent;
cursor: pointer;
border-radius: 15px;
font-weight: 600;
color: #6c757d;
}
.unit-btn.active {
background: white;
color: #3498db;
box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}
.hidden {
display: none;
}
.content-article {
max-width: 800px;
margin: 40px auto;
font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
line-height: 1.6;
color: #333;
}
.content-article h2 {
color: #2c3e50;
border-bottom: 2px solid #ecf0f1;
padding-bottom: 10px;
margin-top: 30px;
}
.content-article ul {
background: #f8f9fa;
padding: 20px 40px;
border-radius: 5px;
}
.content-article table {
width: 100%;
border-collapse: collapse;
margin: 20px 0;
}
.content-article th, .content-article td {
border: 1px solid #ddd;
padding: 12px;
text-align: left;
}
.content-article th {
background-color: #f2f2f2;
}
var currentUnit = 'imperial';
function setUnits(unit) {
currentUnit = unit;
var imperialDiv = document.getElementById('imperialInputs');
var metricDiv = document.getElementById('metricInputs');
var btnImp = document.getElementById('btnImperial');
var btnMet = document.getElementById('btnMetric');
if (unit === 'imperial') {
imperialDiv.style.display = 'block';
metricDiv.style.display = 'none';
btnImp.classList.add('active');
btnMet.classList.remove('active');
} else {
imperialDiv.style.display = 'none';
metricDiv.style.display = 'block';
btnImp.classList.remove('active');
btnMet.classList.add('active');
}
// Hide previous result when switching units to avoid confusion
document.getElementById('result').style.display = 'none';
}
function calculateRMR() {
var age = parseFloat(document.getElementById('age').value);
var gender = document.querySelector('input[name="gender"]:checked').value;
var weightKg = 0;
var heightCm = 0;
// Validation
if (!age || age < 0) {
alert("Please enter a valid age.");
return;
}
if (currentUnit === 'imperial') {
var weightLbs = parseFloat(document.getElementById('weightLbs').value);
var heightFt = parseFloat(document.getElementById('heightFt').value);
var heightIn = parseFloat(document.getElementById('heightIn').value);
// Default inches to 0 if empty but feet provided
if (!heightIn && heightFt) heightIn = 0;
if (!weightLbs || !heightFt) {
alert("Please enter valid weight and height values.");
return;
}
// Conversion to Metric for Formula
weightKg = weightLbs * 0.453592;
heightCm = (heightFt * 30.48) + (heightIn * 2.54);
} else {
weightKg = parseFloat(document.getElementById('weightKg').value);
heightCm = parseFloat(document.getElementById('heightCm').value);
if (!weightKg || !heightCm) {
alert("Please enter valid weight and height values.");
return;
}
}
// Mifflin-St Jeor Formula
// 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;
var baseCalculation = (10 * weightKg) + (6.25 * heightCm) – (5 * age);
if (gender === 'male') {
rmr = baseCalculation + 5;
} else {
rmr = baseCalculation – 161;
}
rmr = Math.round(rmr);
// Display Results
var resultDiv = document.getElementById('result');
var rmrValueDiv = document.getElementById('rmrValue');
rmrValueDiv.innerText = rmr.toLocaleString() + " Calories/day";
// Calculate TDEE Multipliers
document.getElementById('tdeeSedentary').innerText = Math.round(rmr * 1.2).toLocaleString();
document.getElementById('tdeeLight').innerText = Math.round(rmr * 1.375).toLocaleString();
document.getElementById('tdeeMod').innerText = Math.round(rmr * 1.55).toLocaleString();
document.getElementById('tdeeActive').innerText = Math.round(rmr * 1.725).toLocaleString();
resultDiv.style.display = 'block';
}
How to Calculate Resting Metabolic Rate Formula
Understanding your body's energy requirements is the cornerstone of any successful health, fitness, or weight management plan. One of the most critical metrics in this equation is your Resting Metabolic Rate (RMR).
While often used interchangeably with Basal Metabolic Rate (BMR), RMR provides a slightly more practical estimate of the calories your body burns while at rest. This guide explains how to calculate the resting metabolic rate formula, the variables involved, and how to use this number to achieve your goals.
What is Resting Metabolic Rate (RMR)?
Resting Metabolic Rate (RMR) represents the number of calories your body requires to perform basic life-sustaining functions such as breathing, circulating blood, and maintaining organ function while you are at complete rest. It does not include calories burned from digestion (thermic effect of food) or physical activity.
For most people, RMR accounts for approximately 60% to 75% of total daily energy expenditure (TDEE). Knowing this number helps you establish a baseline for how many calories you should consume to lose, gain, or maintain weight.
The Mifflin-St Jeor Formula
While there are several formulas to estimate metabolic rates, the Mifflin-St Jeor equation is widely considered the most accurate for healthy individuals. Developed in 1990, it is the standard used by the calculator above and most clinical dietitians.
The Formula Breakdown
The calculation requires four specific data points: your gender, weight (in kilograms), height (in centimeters), and age (in years).
For Men:
RMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5
For Women:
RMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161
Calculation Example
Let's look at a practical example to understand how the math works manually. Consider a 35-year-old female who weighs 68 kg (150 lbs) and is 165 cm (5'5″) tall.
- Step 1 (Weight): 10 × 68 = 680
- Step 2 (Height): 6.25 × 165 = 1,031.25
- Step 3 (Age): 5 × 35 = 175
- Step 4 (Combine): 680 + 1,031.25 – 175 = 1,536.25
- Step 5 (Gender Adjustment): 1,536.25 – 161 = 1,375.25 Calories/day
This result means that if this individual stayed in bed all day without moving, her body would still burn approximately 1,375 calories just to keep her alive.
RMR vs. BMR: What is the Difference?
You will often see RMR and BMR referenced together. While the math is very similar, the conditions under which they are measured differ slightly:
| Metric |
Conditions |
Accuracy Definition |
| BMR (Basal) |
Measured in a darkened room upon waking after 8 hours of sleep and 12 hours of fasting. |
Highly restrictive, theoretical minimum energy expenditure. |
| RMR (Resting) |
Measured while resting in a seated or supine position, usually 3-4 hours after a light meal. |
More practical, usually about 10% higher than BMR due to digestion and recent movement. |
For the purpose of setting up a diet plan, the calculator provided above uses the parameters for BMR/RMR interchangeably as the difference is negligible for non-clinical applications.
Factors Influencing Your RMR
Your metabolic rate is not a static number. Several factors can influence whether your RMR is higher or lower than the average estimation:
- Muscle Mass: Muscle tissue burns more calories at rest than fat tissue. This is why resistance training is recommended for increasing metabolism.
- Age: As we age, metabolic rate typically slows down, often due to a loss of muscle mass and hormonal changes.
- Genetics: Some individuals naturally have a faster or slower metabolism based on their genetic makeup.
- Hormones: Thyroid imbalances (hypothyroidism or hyperthyroidism) can significantly alter RMR.
- Body Surface Area: Taller and heavier individuals generally have a higher RMR because there is more body tissue to maintain.
From RMR to TDEE
Your RMR is only part of the story. To calculate how many calories you actually burn in a day (Total Daily Energy Expenditure or TDEE), you must multiply your RMR by an activity factor:
- Sedentary (Little to no exercise): RMR × 1.2
- Lightly Active (Exercise 1-3 days/week): RMR × 1.375
- Moderately Active (Exercise 3-5 days/week): RMR × 1.55
- Very Active (Hard exercise 6-7 days/week): RMR × 1.725
Use the calculator at the top of this page to automatically see these estimations based on your RMR result.