Determine your healthy weight range based on scientific formulas.
Male
Female
Kilograms (kg)
Pounds (lbs)
Your Calculated Results:
Robinson Formula (1983)—
Miller Formula (1983)—
Devine Formula (1974)—
Hamwi Formula (1964)—
*Results are estimates based on adult heights over 5 feet (152.4 cm).
What is Ideal Body Weight (IBW)?
Ideal Body Weight (IBW) is a concept designed to provide a target weight for medical purposes, primarily for drug dosing and predicting clinical outcomes. While it doesn't account for muscle mass or body fat percentage, it remains a valuable benchmark for understanding healthy weight ranges for individuals of different heights and genders.
The Science Behind the Formulas
Our calculator uses the four most recognized scientific formulas in the medical community:
The Devine Formula: Created in 1974 by Dr. BJ Devine, it is the most widely used formula for medical dosing.
The Robinson Formula: An improvement on the Devine formula created in 1983 specifically designed for better accuracy in men.
The Miller Formula: Published in 1983, it adjusted previous calculations to provide a more conservative estimate.
The Hamwi Formula: One of the oldest methods (1964), often used by dietitians to determine baseline calorie needs.
Example Calculation
For a male who is 180 cm (approx 5'11") tall:
Height: 180 cm / 2.54 = 70.87 inches.
Inches over 5ft: 10.87 inches.
Devine Formula: 50 kg + (2.3 × 10.87) = 75 kg (165 lbs).
Limitations of These Formulas
It is important to note that these formulas are based strictly on height and gender. They do not distinguish between fat mass and lean muscle mass. For example, a professional athlete may weigh significantly more than their "Ideal Weight" but have a very low body fat percentage and excellent health markers. Always consult with a healthcare professional before making significant changes to your diet or fitness routine.
function calculateIdealWeight() {
var gender = document.getElementById("iw_gender").value;
var heightCm = parseFloat(document.getElementById("iw_height").value);
var unit = document.getElementById("iw_unit").value;
var resultsArea = document.getElementById("iw_results_area");
if (!heightCm || heightCm <= 0) {
alert("Please enter a valid height.");
return;
}
// Convert height to inches
var heightInches = heightCm / 2.54;
// Calculation is usually for height over 5 feet (60 inches)
var inchesOverFive = heightInches – 60;
// Handle cases under 5 feet gracefully (formula still applies linearly but targets become very low)
var robinson, miller, devine, hamwi;
if (gender === "male") {
robinson = 52 + (1.9 * inchesOverFive);
miller = 56.2 + (1.41 * inchesOverFive);
devine = 50 + (2.3 * inchesOverFive);
hamwi = 48 + (2.7 * inchesOverFive);
} else {
robinson = 49 + (1.7 * inchesOverFive);
miller = 53.1 + (1.36 * inchesOverFive);
devine = 45.5 + (2.3 * inchesOverFive);
hamwi = 45.5 + (2.2 * inchesOverFive);
}
// Display results
resultsArea.style.display = "block";
var formulas = {
"res_robinson": robinson,
"res_miller": miller,
"res_devine": devine,
"res_hamwi": hamwi
};
for (var id in formulas) {
var val = formulas[id];
if (unit === "lbs") {
val = val * 2.20462;
document.getElementById(id).innerText = val.toFixed(1) + " lbs";
} else {
document.getElementById(id).innerText = val.toFixed(1) + " kg";
}
}
}