“How much should I weigh?” is one of the most common health questions — and the honest answer is “a range, not a single number.” This guide explains the classic ideal-weight formulas, the healthy BMI range, and, just as importantly, why ideal weight is only a rough guide. For instant numbers, use our free Ideal Weight Calculator.

What “Ideal Weight” Really Means

Ideal body weight (IBW) is an estimate of a typical healthy weight for a given height and sex. Interestingly, the most-used formulas were originally created to help doctors calculate medication doses — not to set fitness goals. That history matters: IBW is a clinical shorthand, useful as a reference point, but never the whole story of a healthy body.

The Healthy Weight Range (BMI)

For most people, the most practical guide is the healthy BMI range: the band of weights that fall within a normal BMI (18.5–24.9) for your height. It’s a range on purpose, because two people of the same height can both be healthy at different weights. For example, at 5’9″ (175 cm) the healthy range is roughly 56–76 kg (124–168 lb). The classic IBW formulas usually land somewhere inside it.

The Four Ideal-Weight Formulas

Each starts from a base weight at 5 feet (60 inches) and adds a set amount per inch above that, in kilograms:

• Devine (1974): Men 50 + 2.3/in · Women 45.5 + 2.3/in — the most cited.
• Robinson (1983): Men 52 + 1.9/in · Women 49 + 1.7/in — refined from insurance tables.
• Miller (1983): Men 56.2 + 1.41/in · Women 53.1 + 1.36/in — usually the highest.
• Hamwi (1964): Men 48 + 2.7/in · Women 45.5 + 2.2/in — popular with dietitians; adjusts ±10% for frame.

They typically agree within a few kilograms, which is why showing all four (plus the BMI range) gives a more honest picture than any single figure.

Ideal Weight by Height (Devine, Medium Frame)

• 5’0″ (152 cm): men ~50 kg / 110 lb · women ~45.5 kg / 100 lb
• 5’4″ (163 cm): men ~59 kg / 130 lb · women ~55 kg / 121 lb
• 5’8″ (173 cm): men ~68 kg / 150 lb · women ~64 kg / 141 lb
• 6’0″ (183 cm): men ~78 kg / 172 lb · women ~73 kg / 161 lb
• 6’4″ (193 cm): men ~87 kg / 192 lb · women ~82 kg / 181 lb

Why Ideal Weight Is Only a Guide

The formulas use only height and sex, so they ignore a lot: muscle mass, bone density, body frame, age, and ethnicity. A muscular, athletic person can weigh well above their “ideal” figure and be in excellent health, because muscle is denser than fat. Likewise, the same weight can look and feel very different on two people. So a number from any formula is best treated as context, not a verdict — and certainly not something to fixate on. If you’re considering changing your weight, a doctor or registered dietitian can give advice tailored to your whole health picture, which is far more useful than a height-only estimate.

Ideal Weight vs BMI vs Body Fat

These three tools complement each other. Ideal weight gives a target figure from height and sex. BMI places your current weight into a category for your height. Body fat percentage measures composition — how much of your body is fat versus lean tissue — and is often the most informative of the three. Looking at all of them together beats relying on any single number.