Ideal Body Weight Calculator

Follow these steps to calculate your ideal body weight:

1. Select your biological gender (male or female). All four formulas use separate equations for men and women because average body composition differs between sexes, with men typically carrying more lean muscle mass at the same height.
2. Enter your height in inches. To convert feet and inches to total inches, multiply feet by 12 and add the remaining inches. For example, 5 feet 8 inches equals 68 inches (5 × 12 + 8 = 68). All formulas use inches above 60 (5 feet) as their reference point, so they are most accurate for heights above 5 feet.
3. Select your body frame size. Choose small, medium, or large based on your bone structure. The simplest test is to wrap your thumb and middle finger around your wrist at the narrowest point. If they overlap, you have a small frame. If they just touch, medium. If they do not touch, large. This adjustment modifies all formula results by minus 10 percent for small frames or plus 10 percent for large frames.

After submitting, you will see ideal weight estimates from all four formulas plus the healthy BMI weight range for your height. The spread between the highest and lowest formula estimates is typically 10 to 20 pounds, which reflects the inherent uncertainty in defining a single ideal weight. Consider the average of all four formulas as a reasonable midpoint and use the healthy BMI range as a broader guideline for setting realistic goals.

An ideal body weight calculator estimates the weight that is generally considered healthiest for a person based on their height, gender, and body frame size. Rather than relying on a single formula, this calculator uses four well-established medical formulas developed over several decades: Devine (1974), Robinson (1983), Miller (1983), and Hamwi (1964). By presenting results from all four, it provides a range of estimates that gives you a more complete picture than any single number could offer.

The concept of ideal body weight was originally developed for clinical purposes, particularly for calculating medication dosages and assessing nutritional status. The Devine formula became the most widely adopted in healthcare settings and is still used today for drug dosing in anesthesia, chemotherapy, and other medical applications. The Robinson and Miller formulas were later refinements that used different study populations, while the Hamwi formula was one of the earliest attempts to define ideal weight based on height.

It is important to understand the limitations of ideal weight formulas. They do not account for body composition, meaning a muscular athlete and a sedentary individual of the same height and gender would receive identical estimates despite having very different body fat percentages. Bone density, ethnic background, age, and genetic factors all influence what a healthy weight looks like for a specific person. Frame size provides a partial adjustment, with small-framed individuals typically weighing less and large-framed individuals weighing more than the baseline estimate. The healthy BMI weight range included in this calculator offers an additional evidence-based reference point, as it is derived from epidemiological data linking body mass index to health outcomes across large populations.

Rather than treating any single formula result as a definitive target, consider the range of estimates and the healthy BMI range together as a guide. Your optimal weight is ultimately one at which you feel healthy, energetic, and capable of maintaining through sustainable lifestyle habits.

Four formulas are used to calculate ideal body weight in kilograms, then converted to pounds and adjusted for frame size. All formulas use inches above 60 (5 feet) as the height variable:

Healthy BMI Range: The calculator also computes the weight range corresponding to a BMI of 18.5 to 24.9 using the formula: Weight (lbs) = BMI × height (m)² × 2.20462, where height in meters = height in inches × 0.0254. This range is derived from World Health Organization guidelines and represents the weight range associated with the lowest risk of weight-related health complications for most adults.

Example 1 — Average Height Male (5'10", 70 inches, medium frame): Inches over 60 = 10. Devine: 50 + 2.3(10) = 73.0 kg = 161 lbs. Robinson: 52 + 1.9(10) = 71.0 kg = 157 lbs. Miller: 56.2 + 1.41(10) = 70.3 kg = 155 lbs. Hamwi: 48 + 2.7(10) = 75.0 kg = 165 lbs. The range spans from 155 to 165 lbs with an average of approximately 159 lbs. The healthy BMI range for this height is 129 to 174 lbs. All four formula estimates fall comfortably within the healthy BMI range, confirming they are reasonable targets.

Example 2 — Shorter Female (5'3", 63 inches, small frame): Inches over 60 = 3. Devine: (45.5 + 2.3 × 3) × 0.9 = 47.1 kg = 104 lbs. Robinson: (49 + 1.7 × 3) × 0.9 = 48.7 kg = 107 lbs. Miller: (53.1 + 1.36 × 3) × 0.9 = 51.5 kg = 113 lbs. Hamwi: (45.5 + 2.2 × 3) × 0.9 = 46.9 kg = 103 lbs. The small frame adjustment reduces all estimates by 10 percent. The range is 103 to 113 lbs. The healthy BMI range for 5'3" is 107 to 141 lbs, so the lower formula estimates approach the lower boundary of healthy BMI.

Example 3 — Tall Male (6'2", 74 inches, large frame): Inches over 60 = 14. Devine: (50 + 2.3 × 14) × 1.1 = 90.4 kg = 199 lbs. Robinson: (52 + 1.9 × 14) × 1.1 = 86.5 kg = 191 lbs. Miller: (56.2 + 1.41 × 14) × 1.1 = 83.5 kg = 184 lbs. Hamwi: (48 + 2.7 × 14) × 1.1 = 94.4 kg = 208 lbs. The large frame adjustment increases all estimates by 10 percent. The range spans from 184 to 208 lbs, a 24-pound spread that reflects the greater variation among formulas at taller heights. The healthy BMI range for 6'2" is 144 to 194 lbs, meaning the Hamwi estimate exceeds the upper BMI boundary, illustrating why comparing multiple formulas provides useful context.