Calculate your medically recommended body weight using industry-standard formulas.
Male
Female
Biological sex affects body composition calculations.
Enter your height in centimeters. (e.g., 5ft 9in is approx 175 cm)
Please enter a valid height between 50 and 300 cm.
Estimated Ideal Weight (Devine Formula)
— kg
Based on the 1974 Devine Formula, widely used in medical dosage calculations.
Comparison of Different Ideal Weight Formulas
Method
Estimated Weight
Description
Healthy BMI Range (WHO):—
What is an Ideal Weight Calculator?
An ideal weight calculator is a specialized health tool designed to estimate the optimal body weight for an individual based on specific physiological factors such as height, gender, and sometimes body frame size. Unlike a generic scale, this calculator uses medically established algorithms to provide a target weight range associated with maximum longevity and minimal risk of chronic diseases.
This tool is essential for anyone looking to set realistic fitness goals, medical professionals calculating medication dosages, or individuals monitoring their health status. While the concept of "ideal weight" varies between individuals due to muscle mass and bone density, these formulas provide a clinically accepted baseline.
Common misconceptions include believing there is a single "perfect" number. In reality, a healthy weight is a range. The ideal weight calculator aggregates data from multiple renowned formulas (Devine, Robinson, Miller, and Hamwi) to give you a comprehensive perspective rather than a single data point.
Ideal Weight Calculator Formulas and Mathematical Explanation
The calculation of ideal body weight (IBW) relies on empirical equations developed by researchers over the last century. Most of these formulas are based on a base weight for a specific height (usually 5 feet) and add a set amount of weight for every inch over that height.
Variables Used
Key Variables in Weight Calculations
Variable
Meaning
Unit
Typical Range
H
Height
Inches (calculated from cm)
60 – 80 inches
Base
Base Weight at 5ft
Kilograms (kg)
45 – 56 kg
Rate
Weight added per inch over 5ft
kg per inch
1.4 – 2.7 kg
The Formulas
Here is the mathematical breakdown of the four primary formulas used in this ideal weight calculator:
1. Devine Formula (1974)
Originally designed for calculating drug dosages, this is the most widely used formula in medicine.
Men: 50 kg + 2.3 kg × (Height in inches – 60)
Women: 45.5 kg + 2.3 kg × (Height in inches – 60)
2. Robinson Formula (1983)
A modification of the Devine formula to improve accuracy for modern anthropometric data.
Men: 52 kg + 1.9 kg × (Height in inches – 60)
Women: 49 kg + 1.7 kg × (Height in inches – 60)
3. Miller Formula (1983)
Often produces lower estimates for weight, considered by some to be more aligned with "lean" body mass.
Men: 56.2 kg + 1.41 kg × (Height in inches – 60)
Women: 53.1 kg + 1.36 kg × (Height in inches – 60)
Practical Examples (Real-World Use Cases)
To better understand how the ideal weight calculator functions, let's look at two distinct examples.
Example 1: The Average Male
Profile: John is a 30-year-old male, 180 cm (approx 5ft 11in) tall.
Input Height: 180 cm (~70.9 inches)
Inches over 60: 10.9 inches
Calculation (Devine): 50 + (2.3 × 10.9) = 75.07 kg
Calculation (Robinson): 52 + (1.9 × 10.9) = 72.71 kg
Interpretation: John's ideal weight falls roughly between 72 kg and 75 kg. If he weighs 90 kg, he might consider a weight loss plan. If he is a bodybuilder, the extra weight might be muscle, making BMI less relevant.
Example 2: The Petite Female
Profile: Sarah is a 25-year-old female, 158 cm (approx 5ft 2in) tall.
Input Height: 158 cm (~62.2 inches)
Inches over 60: 2.2 inches
Calculation (Devine): 45.5 + (2.3 × 2.2) = 50.56 kg
Calculation (Hamwi): 45.5 + (2.2 × 2.2) = 50.34 kg
Interpretation: Sarah's results are very consistent across formulas, suggesting a target weight of approximately 50.5 kg. This precision helps her set a specific health goal.
How to Use This Ideal Weight Calculator
Select Gender: Choose Male or Female. This is critical as men generally have higher bone density and muscle mass, affecting the base calculation.
Enter Height: Input your height in centimeters. If you know your height in feet/inches, convert it first (1 inch = 2.54 cm).
Review the Primary Result: The large highlighted number uses the Devine formula, which is the medical standard.
Compare Methods: Look at the comparison table to see the range provided by Robinson, Miller, and Hamwi formulas.
Check BMI Range: The result section also displays the World Health Organization's "Normal" BMI weight range for your height.
Key Factors That Affect Ideal Weight Results
While an ideal weight calculator provides a solid baseline, several real-world factors influence what your specific "best" weight should be:
Muscle Mass vs. Fat: Muscle tissue is denser than fat. Athletes may weigh significantly more than their "ideal" calculator result while having low body fat and excellent health.
Body Frame Size: The Hamwi formula attempts to account for this by suggesting a ±10% adjustment for small or large frames. A person with a broad skeletal structure naturally weighs more.
Age: As we age, muscle mass tends to decrease and metabolism slows. Some research suggests slightly higher weight ranges in older adults may be protective.
Bone Density: Genetic variances in bone density contribute to total mass without reflecting obesity or health risks.
Pregnancy and Nursing: These formulas do NOT apply to pregnant or nursing women, where weight gain is necessary and physiological.
Health History: Individuals recovering from illness or with specific metabolic conditions may have different healthy weight targets determined by a doctor.
Frequently Asked Questions (FAQ)
Why are there so many different formulas?
Different formulas were developed in different decades and based on different population data. The Devine formula (1974) is standard for medical dosing, while the Robinson formula (1983) updated the data for newer population averages.
Which ideal weight result should I trust?
For most people, the Devine formula is the safest benchmark. However, looking at the range provided by all formulas gives a better picture than relying on a single number.
Does this calculator apply to children?
No. Children and adolescents require specialized growth charts (CDC or WHO percentiles) because their bodies are still developing. This ideal weight calculator is for adults (18+).
I am an athlete. Is this accurate for me?
Likely not. These formulas generally assume a sedentary to moderately active population. Athletes with high muscle mass will often be classified as "overweight" by these formulas despite being healthy.
What if my height is under 5 feet?
Most IBW formulas are based on a height of 5 feet plus increments. For heights under 5 feet, the calculator extrapolates backward, but results may be less reliable. BMI is often a better metric for shorter stature.
Is Ideal Body Weight the same as BMI?
No. BMI (Body Mass Index) is a ratio of weight to height. IBW calculates a specific weight in kilograms. However, a healthy IBW usually falls within the normal BMI range (18.5–24.9).
Can I use this for weight loss goals?
Yes, it is an excellent tool for setting long-term goals. However, always consult a healthcare provider before starting a drastic weight loss regimen.
Why is gender required?
Men and women have different essential body fat percentages and hormonal profiles, leading to different healthy weight distributions.
Related Tools and Internal Resources
Enhance your health and financial planning with our other dedicated tools:
// Global variable to hold the chart instance if we were using a library,
// but since we use raw canvas, we redraw completely.
var canvas = document.getElementById('weightChart');
var ctx = canvas.getContext('2d');
// Initialization
window.onload = function() {
// Set a default height to prompt user interaction or show empty state
// We leave inputs empty by default as per good UX for calculators requiring specific user data
// But we can trigger a calc if defaults existed.
resizeCanvas();
};
window.onresize = function() {
resizeCanvas();
if(document.getElementById('heightCm').value) {
calculateIdealWeight();
}
};
function resizeCanvas() {
var container = canvas.parentElement;
canvas.width = container.clientWidth;
canvas.height = container.clientHeight;
}
function calculateIdealWeight() {
var gender = document.getElementById('gender').value;
var heightCm = parseFloat(document.getElementById('heightCm').value);
var heightError = document.getElementById('heightError');
var resultsSection = document.getElementById('resultsSection');
// Validation
if (!heightCm || isNaN(heightCm) || heightCm 300) {
if (document.getElementById('heightCm').value !== "") {
heightError.style.display = "block";
}
resultsSection.style.display = "none";
return;
}
heightError.style.display = "none";
resultsSection.style.display = "block";
// Conversion
var heightInches = heightCm / 2.54;
var heightOver60 = heightInches – 60;
// Ensure we handle heights under 5ft (negative heightOver60) purely mathematically as per formulas,
// though clinically less accurate.
// 1. Devine Formula
var devine = 0;
if (gender === 'male') {
devine = 50 + (2.3 * heightOver60);
} else {
devine = 45.5 + (2.3 * heightOver60);
}
// 2. Robinson Formula
var robinson = 0;
if (gender === 'male') {
robinson = 52 + (1.9 * heightOver60);
} else {
robinson = 49 + (1.7 * heightOver60);
}
// 3. Miller Formula
var miller = 0;
if (gender === 'male') {
miller = 56.2 + (1.41 * heightOver60);
} else {
miller = 53.1 + (1.36 * heightOver60);
}
// 4. Hamwi Formula
var hamwi = 0;
if (gender === 'male') {
hamwi = 48 + (2.7 * heightOver60);
} else {
hamwi = 45.5 + (2.2 * heightOver60);
}
// BMI Range (18.5 – 25)
var heightM = heightCm / 100;
var minBMIWeight = 18.5 * (heightM * heightM);
var maxBMIWeight = 25 * (heightM * heightM);
// Update DOM
document.getElementById('mainResult').innerText = devine.toFixed(1) + " kg";
// Update BMI Text
document.getElementById('bmiRangeResult').innerText = minBMIWeight.toFixed(1) + " kg – " + maxBMIWeight.toFixed(1) + " kg";
// Update Table
var tbody = document.getElementById('comparisonTableBody');
tbody.innerHTML = "";
var formulas = [
{ name: "Devine", val: devine, desc: "Standard medical formula" },
{ name: "Robinson", val: robinson, desc: "Modified for modern averages" },
{ name: "Miller", val: miller, desc: "Often lower, estimates lean mass" },
{ name: "Hamwi", val: hamwi, desc: "Adjusts heavily for frame size" }
];
for (var i = 0; i < formulas.length; i++) {
var row = "
";
row += "
" + formulas[i].name + "
";
row += "
" + formulas[i].val.toFixed(1) + " kg
";
row += "
" + formulas[i].desc + "
";
row += "
";
tbody.innerHTML += row;
}
// Draw Chart
drawChart([devine, robinson, miller, hamwi], ["Devine", "Robinson", "Miller", "Hamwi"]);
}
function drawChart(dataValues, labels) {
var width = canvas.width;
var height = canvas.height;
var padding = 40;
var bottomMargin = 40;
var chartHeight = height – bottomMargin – padding;
var chartWidth = width – (padding * 2);
// Clear canvas
ctx.clearRect(0, 0, width, height);
// Find max value for scaling
var maxVal = 0;
for(var i=0; i maxVal) maxVal = dataValues[i];
}
maxVal = maxVal * 1.2; // Add headroom
// Draw bars
var barWidth = (chartWidth / dataValues.length) – 20;
var startX = padding;
for(var i=0; i<dataValues.length; i++) {
var val = dataValues[i];
var barHeight = (val / maxVal) * chartHeight;
var x = startX + (i * (barWidth + 20));
var y = height – bottomMargin – barHeight;
// Draw Bar
ctx.fillStyle = "#004a99";
ctx.fillRect(x, y, barWidth, barHeight);
// Draw Value on top
ctx.fillStyle = "#000";
ctx.font = "bold 14px Arial";
ctx.textAlign = "center";
ctx.fillText(val.toFixed(1) + "kg", x + (barWidth/2), y – 10);
// Draw Label below
ctx.fillStyle = "#555";
ctx.font = "12px Arial";
ctx.fillText(labels[i], x + (barWidth/2), height – 10);
}
}
function resetCalculator() {
document.getElementById('gender').value = "male";
document.getElementById('heightCm').value = "";
document.getElementById('resultsSection').style.display = "none";
document.getElementById('heightError').style.display = "none";
// Clear chart
ctx.clearRect(0, 0, canvas.width, canvas.height);
}
function copyResults() {
var gender = document.getElementById('gender').value;
var height = document.getElementById('heightCm').value;
var result = document.getElementById('mainResult').innerText;
var bmiRange = document.getElementById('bmiRangeResult').innerText;
if(!height) return;
var text = "Ideal Weight Calculator Results:\n";
text += "Gender: " + gender + "\n";
text += "Height: " + height + " cm\n";
text += "Devine Formula (Primary): " + result + "\n";
text += "Healthy BMI Range: " + bmiRange + "\n";
text += "Generated by Ideal Weight Calculator";
var tempInput = document.createElement("textarea");
tempInput.value = text;
document.body.appendChild(tempInput);
tempInput.select();
document.execCommand("copy");
document.body.removeChild(tempInput);
var btn = document.querySelector('button.success');
var originalText = btn.innerText;
btn.innerText = "Copied!";
setTimeout(function(){ btn.innerText = originalText; }, 2000);
}