Ideal Weight Calculator
See your healthy weight range across five peer-reviewed formulas, side-by-side.
Enter your height to see your ideal weight
Five peer-reviewed formulas, side-by-side — plus the BMI-based healthy range for your height.
How to use this calculator
- 1
Pick your units
Imperial (ft / in) or metric (cm). The form swaps over instantly.
- 2
Enter your sex and height
These two inputs are all the formulas need. None of the legacy equations use age, weight, or body composition.
- 3
Read your results
Your BMI-based healthy weight range sits at the top — that's usually the most useful answer. Below it, the four legacy formulas (Devine, Robinson, Miller, Hamwi) each give a single point estimate. The visual scale shows where each one falls relative to the BMI band.
What is “ideal” weight?
“Ideal body weight” is a clinical term that originated in pharmacy and medicine — most of the well-known formulas were created to help dose medication for patients of different sizes, not to prescribe a target weight for health. The name stuck, and they got adopted into general fitness and nutrition contexts where they don't always fit cleanly.
The honest framing is: ideal weight formulas give you a reference point— a rough centre of gravity for what an average adult of your height tends to weigh when healthy. They don't account for body composition (muscle vs fat), frame size, fitness, age-related changes, or any individual variability. Two people who weigh exactly their “ideal” weight can have wildly different body compositions and very different health.
For most practical purposes, the BMI-based healthy weight range (18.5–24.9) is more useful than any single “ideal” number, because it's a range rather than a single target. We show both so you can see how the legacy formulas compare to the modern WHO range.
How is ideal weight calculated?
All four legacy point-estimate formulas share the same template: a base weight at 5 ft (60 inches) tall, plus a fixed amount of weight for each additional inch of height. They differ only in the base value and the per-inch coefficient.
Devine (1974)
The most widely used formula in clinical practice, originally developed for gentamicin dosing. Still the standard reference for drug-dosing calculations.
Men: IBW = 50 kg + 2.3 × (height_in − 60)
Women: IBW = 45.5 kg + 2.3 × (height_in − 60)
Robinson (1983)
A revision of Devine, also published in a pharmacy journal. Uses slightly lower per-inch coefficients, producing more conservative estimates at taller heights.
Men: IBW = 52 kg + 1.9 × (height_in − 60)
Women: IBW = 49 kg + 1.7 × (height_in − 60)
Miller (1983)
A second 1983 revision with even lower per-inch coefficients. Tends to give the lowest estimates of the four for tall adults.
Men: IBW = 56.2 kg + 1.41 × (height_in − 60)
Women: IBW = 53.1 kg + 1.36 × (height_in − 60)
Hamwi (1964)
The original simple rule, still taught in nursing schools. Uses the highest per-inch coefficient of the four, so it tends to give the highest estimates at taller heights.
Men: IBW = 48 kg + 2.7 × (height_in − 60)
Women: IBW = 45.5 kg + 2.2 × (height_in − 60)
BMI-based healthy weight range
Derived from the WHO healthy BMI range (18.5–24.9) applied to your height. Returns a span (min–max) rather than a single number, which is typically more practical than picking one point estimate.
Min = 18.5 × height_m²
Max = 24.9 × height_m²
In practice
Use the BMI-based range as your primary reference. The four legacy point estimates are there for context — to show that even “ideal” weight is itself an approximation that varies depending on which formula you ask. None of them substitute for a body composition check (body fat %, waist-to-hip ratio) when that level of detail matters.
Frequently asked questions
Sources & references
Original papers and clinical references for each formula.
- Devine BJ (1974). Gentamicin therapy. Drug Intelligence and Clinical Pharmacy 8:650–655. The original ideal-body-weight formula; widely used clinically for drug dosing. Pre-PubMed era — no online open-access link available.
- Robinson JD, Lupkiewicz SM, Palenik L, Lopez LM, Ariet M (1983). Determination of ideal body weight for drug dosage calculations. Am J Hosp Pharm 40:1016–1019. PubMed
- Miller DR, Carlson JD, Loyd BJ, Day BJ (1983). Determining ideal body weight (and mass). Am J Hosp Pharm 40:1622–1625. PubMed
- Hamwi GJ (1964). Therapy: changing dietary concepts. In: Diabetes Mellitus: Diagnosis and Treatment, vol. 1. American Diabetes Association. Textbook reference — no online link.
- WHO. Obesity and overweight — canonical fact sheet covering the BMI cutpoints (18.5–24.9 healthy range) used in the BMI-based span shown above. WHO Fact Sheet
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