The four formulas used here
No single formula defines ideal weight. Doctors use four main ones, each developed from different patient populations.
Devine (1974): Male = 50 + 2.3 × (height in inches − 60). Female = 45.5 + 2.3 × (height in inches − 60). Originally created to calculate drug dosages, not body ideals. Most widely used in clinical settings.
Robinson (1983): Male = 52 + 1.9 × (height in inches − 60). Female = 49 + 1.7 × (height in inches − 60). Slightly higher for men at taller heights.
Miller (1983): Male = 56.2 + 1.41 × (height in inches − 60). Female = 53.1 + 1.36 × (height in inches − 60). Gives higher estimates, especially for taller frames.
Hamwi (1964): Male = 48 + 2.7 × (height in inches − 60). Female = 45.5 + 2.2 × (height in inches − 60). The oldest formula, still used in clinical nutrition.
The range shown in the calculator is the spread across all four. A 170 cm Indian man, for example, gets an ideal weight range of roughly 60–66 kg depending on which formula you use.
Ideal weight vs healthy weight range
These are different things. Ideal weight formulas give a single point estimate (with some spread). Healthy weight range is based on BMI 18.5–24.9, which for a 170 cm person means 53.5–72 kg. The range is wider.
Most people fall somewhere between the two. The formulas above were built on Western populations in the 1960s–80s. Indian adults tend to have higher body fat at the same BMI compared to Caucasians — a well-established finding in Indian metabolic research. The WHO and ICMR suggest lower BMI cutoffs for Asians (overweight starts at 23, not 25). This calculator uses standard formulas but keep the Asian context in mind.
What actually matters more than the number
Waist circumference tells you more about metabolic risk than ideal weight. For Indian men, waist above 90 cm significantly raises risk of type 2 diabetes and cardiovascular disease. For Indian women, above 80 cm. A person at their “ideal weight” with central obesity is still at risk.
The BMI calculator gives a population-level health benchmark. The body fat calculator gets closer to actual body composition. Ideal weight formulas are starting points, not diagnoses.
Sources
- Devine BJ — “Gentamicin therapy,” Drug Intelligence and Clinical Pharmacy, 1974 — original ideal body weight formula for drug dosing
- Robinson JD et al. — “Determination of ideal body weight for drug dosage calculations,” American Journal of Hospital Pharmacy, 1983
- Misra A et al. — “Consensus statement for diagnosis of obesity, abdominal obesity and the metabolic syndrome for Asian Indians and recommendations for physical activity, medical and surgical management,” Journal of the Association of Physicians of India, 2009