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Ideal Weight Calculator

Calculate ideal body weight using Devine, Robinson, Miller, and Hamwi formulas.

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.

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 was originally 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 formulas give different results?
Each formula was derived 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 formulas suitable for children or athletes?
No. These formulas were developed for adult populations. For children, paediatric growth charts are more appropriate. For athletes with high muscle mass, BMI and these formulas may underestimate healthy weight — body composition analysis is more useful.

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