Ideal weight calculator
Ideal body weight (IBW) formulas estimate a reference weight from height and sex — commonly used in medicine for drug dosing and nutritional screening.
How to calculate ideal weight
1. Enter your height and sex (formulas differ for men and women).
2. Read IBW from Devine, Robinson, and Miller — note the small spread between them.
3. Compare with the BMI 18.5–24.9 weight band for your height.
4. Use the range as context for goals; athletes with high muscle may sit above IBW while healthy.
Ideal weight examples
Man, 178 cm (5 ft 10 in)
Devine IBW ≈ 73.0 kg; Robinson ≈ 72.6 kg; Miller ≈ 72.1 kg. BMI 18.5–24.9 spans roughly 59–79 kg — IBW sits near the middle-upper part of that band.
Woman, 165 cm (5 ft 5 in)
Devine IBW ≈ 61.5 kg; Robinson ≈ 59.9 kg; Miller ≈ 59.1 kg. BMI healthy range ≈ 50–68 kg — all three IBW estimates fall comfortably inside.
IBW vs your current weight
At 82 kg and 178 cm, you may be above IBW but still in a healthy BMI (≈25.9, borderline overweight). IBW is one clinical shortcut; body composition and waist health matter too.
When to use this tool
• When you compare clinical IBW formulas for nursing, pharmacy, or exam prep.
• When you want a height-based reference alongside BMI boundaries.
• When you discuss realistic targets with a coach or clinician using standard IBW tables.
IBW vs BMI — two different tools
BMI = weight ÷ height² and categorizes underweight, normal, overweight, and obese in populations. IBW formulas were designed to pick one target weight for dosing antibiotics, ventilation settings, or fluid rules — not to define aesthetics. A BMI of 22 and an IBW of 68 kg might align for a given height, but BMI accepts a range while IBW gives a point. Neither measures visceral fat, lipids, or fitness.
Frequently asked questions
What is the Devine formula?
For men: 50 + 2.3 kg per inch over 5 ft. For women: 45.5 + 2.3 kg per inch over 5 ft. It dates from 1974 and remains common in drug dosing charts.
How do Robinson and Miller differ?
They use different base weights and inches-per-kg slopes. Robinson often runs slightly lower for women; Miller slightly lower for men. All three are approximations.
Is ideal weight the same as healthy weight?
Not exactly. BMI ranges describe population health bands; IBW formulas target a single number for clinical convenience. Healthy people can sit above or below IBW.
Why does IBW ignore muscle mass?
Formulas use only height and sex. A lifter at 85 kg may be lean; IBW does not distinguish muscle from fat.
Which formula should I follow?
Medical contexts often cite Devine. For personal goals, treat the trio as a narrow band (~1–2 kg spread) inside the wider BMI range.