Ideal Weight Calculator

What is an Ideal Weight Calculator?

An ideal weight calculator estimates the body weight that is typically associated with the lowest health risk for a given height and sex. The concept originated in life-insurance actuarial tables in the early 20th century and was later refined into several predictive formulas — Devine (1974), Robinson (1983), Miller (1983), and Hamwi (1964) are the most widely used. Each formula was designed for a specific clinical purpose: Devine, for instance, was originally developed to improve medication dosing in adults and is still embedded in many pharmacokinetic calculations today.

It is important to understand that "ideal" weight is a population-level approximation, not a personal prescription. Two people of the same height can be perfectly healthy at weights that differ by 10 kg because of differences in muscle mass, frame size, bone density, and fat distribution. For this reason, modern clinical practice treats ideal weight as a useful reference point rather than a target to be hit exactly, and pairs it with body mass index (BMI), waist circumference, and body composition measures for a more complete picture.

Still, having a reasonable benchmark has real value. It helps set realistic goals when planning weight loss or gain, provides a starting point for calorie targets, and gives clinicians a normalized reference for drug dosing, ventilator settings, and anesthesia.

How is it Calculated?

Common formulas for an adult with height above 152 cm (5 ft) — add or subtract per inch over 5 ft:

• Devine: Men 50 + 2.3 × (inches over 5 ft); Women 45.5 + 2.3 × (inches over 5 ft)
• Robinson: Men 52 + 1.9 × (inches over 5 ft); Women 49 + 1.7 × (inches over 5 ft)
• Miller: Men 56.2 + 1.41 × (inches over 5 ft); Women 53.1 + 1.36 × (inches over 5 ft)
• BMI-based range: Healthy weight = 18.5–24.9 × height(m)²

Worked example:A man 175 cm tall (about 5 ft 9 in, 9 inches over 5 ft). Devine = 50 + 2.3 × 9 = 70.7 kg. Robinson = 52 + 1.9 × 9 = 69.1 kg. Miller = 56.2 + 1.41 × 9 = 68.9 kg. Average ≈ 69.6 kg. The healthy BMI range for this height is roughly 56.6–76.3 kg — showing that a range, not a single number, is the more realistic goal.

Tips for Interpreting Your Result

• Use ideal weight as a ballpark, not a strict target — health exists across a range.
• Combine with waist circumference: above 102 cm (men) or 88 cm (women) raises cardiometabolic risk regardless of weight.
• Muscle is denser than fat; a strength-trained person may exceed ideal weight while having excellent health markers.
• Frame size adjusts the target: people with larger frames can be healthy 5–10% above the formula result.
• Focus on behaviors (nutrition quality, activity, sleep) rather than chasing a specific number on the scale.

Frequently Asked Questions