Ideal Weight Calculator

What Is Ideal Body Weight?

Ideal Body Weight (IBW) is an estimated weight range considered optimal for your height and gender, associated with the lowest risk of weight-related health complications. It is widely used in medicine to calculate medication dosages, assess nutritional needs, and provide a benchmark for weight management goals.

It is important to understand from the outset that no formula can define a universally perfect weight. Individual variations in bone density, muscle mass, body proportions, and genetic factors mean that two people of the same height and gender can be equally healthy at different weights. IBW formulas provide a useful starting point — not a strict target.

The Four Major IBW Formulas

Our calculator computes your ideal weight using all four major clinical formulas and displays a range, giving you a more nuanced picture than any single formula alone.

1. Devine Formula (1974)

The most commonly cited formula in clinical medicine:

• Men: IBW = 50 + 2.3 × (Height in inches − 60)
• Women: IBW = 45.5 + 2.3 × (Height in inches − 60)

2. Hamwi Formula (1964)

The oldest of the four formulas, developed for clinical use:

• Men: IBW = 48 + 2.7 × (Height in inches − 60)
• Women: IBW = 45.5 + 2.2 × (Height in inches − 60)

3. Robinson Formula (1983)

Developed to improve accuracy over the Devine formula:

• Men: IBW = 52 + 1.9 × (Height in inches − 60)
• Women: IBW = 49 + 1.7 × (Height in inches − 60)

4. Miller Formula (1983)

Tends to produce lower estimates than the others:

• Men: IBW = 56.2 + 1.41 × (Height in inches − 60)
• Women: IBW = 53.1 + 1.36 × (Height in inches − 60)

All four formulas require height to be above 60 inches (5 feet). For individuals under 5 feet, these formulas are not clinically validated, and paediatric growth charts should be used instead.

Why Different Formulas Give Different Results

Each formula was derived from a different clinical population and study methodology. The Devine formula was developed for pharmacokinetic dosing calculations and has been widely adopted even outside its original context. The Hamwi formula was designed for clinical nutrition assessments. Robinson and Miller attempted to refine Devine based on updated population data.

The variation between formulas is typically 3–8 kg for most heights, which is why our calculator presents a range rather than a single number.

IBW in the Indian Context

Indian adults generally have a lower average height and different body composition profiles compared to Western populations on which these formulas were originally derived. Research has shown that South Asians tend to accumulate more visceral (abdominal) fat at lower BMI and weight levels, increasing metabolic risk earlier than the Western-derived formulas might suggest.

For Indian adults, some healthcare professionals recommend targeting the lower end of the IBW range as a precautionary approach to metabolic health. Always consult a registered dietitian or physician for personalised guidance.

Moving Beyond a Single Number

For the most comprehensive understanding of your weight and health status, use these tools together:

1. BMI Calculator — Classifies your weight relative to height in broad categories.
2. Ideal Weight Calculator (this tool) — Gives a clinical target weight range.
3. Body Fat Calculator — Tells you what proportion of your weight is fat vs. lean mass.
4. Calorie Calculator — Helps you create a sustainable plan to reach or maintain your ideal weight through nutrition.

Together, these four tools give you a multi-dimensional view of your body composition and a practical roadmap for improving it.