Ideal Weight Calculator

What is ideal body weight?

Ideal body weight (IBW) is an estimate of the optimal weight for a given height, originally developed to calculate medication dosages in clinical settings. The most commonly cited formulas — Devine, Robinson, Miller, and Hamwi — were all published between 1974 and 1983 and are still referenced in pharmacology and medicine today.

These are estimates, not targets. Actual healthy weight depends on muscle mass, bone density, body composition, age, and individual health factors.

BMI-based healthy range

The World Health Organization defines a healthy BMI as 18.5–24.9. Converting this to a weight range for your height gives a practical target zone used by most doctors and nutritionists. This range is wider than individual formula estimates and reflects the natural diversity in healthy body weights.

Beyond the number

Weight is one metric among many. Waist circumference, body fat percentage, blood markers, fitness level, and energy are equally important. Focus on sustainable habits — consistent exercise, adequate protein, quality sleep — rather than hitting a specific number on the scale.

The four formulas compared

The Devine formula (1974) is the most commonly referenced in clinical pharmacology and is used to calculate medication doses. TheRobinson formula (1983) gives slightly lower estimates, especially for women. The Miller formula (1983) gives the lowest estimates overall. The Hamwi formula (1964) is the oldest and gives higher values than the others. The average of the four formulas is often more reliable than any single one — which is why this calculator shows all four together.

Ideal weight for Indians — population considerations

The ideal weight formulas were developed on Western populations in the 1960s–1980s. Research on South Asian body composition shows that Indians tend to have higher body fat percentages at the same BMI and weight compared to Caucasians. This means the formula-derived ideal weights may be slightly high for Indian adults when used for health risk assessment. For weight management goals, the BMI-based range (especially the lower end, targeting BMI 20–22) is a more appropriate benchmark for most Indians than the formula averages.

How to use your ideal weight target

Use the BMI-based range as a realistic weight goal bracket rather than targeting a single number. If you are currently above the range, focus on a sustainable rate of loss (0.5–1 kg per week) rather than crash dieting. If you are below the range (underweight), a structured strength training programme combined with a caloric surplus will help you gain lean mass and reach a healthier weight. Consult a doctor or registered dietitian before starting any significant weight change programme.

Frequently asked questions

What is the Devine formula?

The Devine formula (1974) is the most widely used in clinical and medical settings. For men: IBW = 50 kg + 2.3 kg per inch over 5 feet. For women: IBW = 45.5 kg + 2.3 kg per inch over 5 feet. It w created for drug dosage calculations.

Which ideal weight formula is most accurate?

No single formula is universally accurate. All four formulas (Devine, Robinson, Miller, Hamwi) were developed for clinical drug dosing, not fitness goals. The BMI-based range (18.5–24.9) is generally more appropriate for general health assessment.

Why do different formul different results?

Each formula w from different study populations and time periods. The differences are usually small (2–5 kg) and represent the natural variation in ideal weight estimates across research studies.

What is the BMI healthy weight range?

BMI (Body Mass Index) between 18.5 and 24.9 is considered the healthy range. The BMI-based weight range shown here is calculated as: weight = BMI × height² (in metres). This gives a range rather than a single target.

Are these formul for children or athletes?

No. These formul developed for adult populations. For children, paediatric growth charts are more appropriate. For athletes with high muscle mass, BMI and these formul underestimate healthy weight — body composition analysis is more useful.