How to Find Your Ideal Weight
There is no single "ideal" weight — it varies based on height, sex, frame size, age and body composition. The formulas below give ranges rather than exact numbers, which is more realistic. Two people of the same height can have very different ideal weights depending on their muscle mass and frame.
The BMI Range Method
The most widely used method is to find the weight range corresponding to a healthy BMI (18.5–24.9). For a person 175cm tall: lower bound = 18.5 × 1.75² = 56.6 kg; upper bound = 24.9 × 1.75² = 76.2 kg. This gives a healthy range of 56.6–76.2 kg.
Devine and Robinson Formulas
The Devine formula (1974) was originally developed for calculating drug dosages in clinical settings: Men: 50 + 2.3 × (height in inches − 60); Women: 45.5 + 2.3 × (height in inches − 60). The Robinson (1983) and Miller (1983) formulas are refinements with slightly different constants. These are now considered less appropriate for general weight goals than the BMI range.
Frequently Asked Questions
What is my ideal weight?
Ideal weight depends on height, frame size, age and sex. Common formulas (Devine, Hamwi, Robinson) suggest a range rather than a single number. A 5'10" (178 cm) man's ideal weight range is roughly 65–80 kg depending on the formula. BMI 18.5–24.9 is another common healthy range guide.
Which ideal weight formula is most accurate?
No single formula is universally accurate — all are estimates. The BMI-based range is the most widely used. Devine and Hamwi formulas were developed for clinical drug dosing and are less appropriate for everyday weight goals. Body fat percentage combined with height is the most accurate individual measure.
Does frame size affect ideal weight?
Yes. People with larger bone structure and frame size naturally weigh more. A simple frame size test: wrap your thumb and middle finger around your wrist. If they don't meet, you have a large frame; if they just touch, medium; if they overlap, small. Most ideal weight formulas give a range of 10% either side for this reason.
Is BMI the best way to check healthy weight?
BMI is a useful screening tool but has limitations — it doesn't distinguish fat from muscle, doesn't account for fat distribution, and has different health risk thresholds for different ethnicities. For a more accurate picture, combine BMI with waist circumference and body fat percentage.
What is a healthy BMI range?
The standard healthy BMI range is 18.5–24.9 for most adults. Underweight is below 18.5, overweight is 25–29.9, obese is 30+. For people of South Asian, East Asian or Southeast Asian descent, health organisations recommend lower thresholds — healthy range is approximately 18.5–22.9 due to higher health risks at lower BMI values.