Ideal Body Weight Calculator
Find your ideal body weight from height and sex using five formulas — Devine, Robinson, Miller, Hamwi, and the modern Peterson (2016) — plus your healthy BMI range.
“Ideal body weight” is an estimate of a healthy weight for your height and sex. It was originally devised to help doctors dose medications, and it remains a handy reference point — as long as you treat it as a range, not a verdict. Many people search for it as an “ideal weight calculator”; the two names mean the same thing. Enter your height in centimetres or in feet and inches — the calculator converts automatically and shows results in kilograms and pounds.
The five formulas
This calculator shows five equations side by side, plus their average, because no single one is authoritative:
- Devine (1974) — the most widely used, especially in medicine.
- Robinson (1983) — a refinement of Devine, usually a little lower.
- Miller (1983) — another refinement, typically the lowest for tall people.
- Hamwi (1964) — the oldest, often the highest.
- Peterson (2016) — a modern, validated equation that works across the whole height range and doesn’t split by sex; it’s anchored to a healthy target BMI.
The four classic formulas share a shape: a base weight for someone 5 feet (152 cm) tall, plus a fixed amount for every inch above that. Devine, the most common, uses a base of 50 kg for men (45.5 kg for women) and adds 2.3 kg per inch over 5 feet — so a 5-foot-10 man works out to 50 + (10 × 2.3) = 73 kg (about 161 lb). Peterson instead scales directly with height against a target BMI of 22.
The healthy BMI range
Because those formulas use only height and sex, the calculator also shows your healthy weight range from the BMI 18.5–25 band. That range is often the more useful answer: it gives a band of healthy weights rather than one target, which leaves room for different builds. If a range is really what you’re after, our healthy weight calculator focuses on it, and the BMI calculator shows where your current weight already sits on the scale.
Read it as a guide, not a goal
None of these methods know your muscle mass, frame size, or body composition. A strong, muscular person can sit well above their “ideal” weight and be perfectly healthy. Use the number as a rough anchor, and combine it with your body fat percentage, waist measurements, and how you actually feel.
Frequently asked questions
What is my ideal weight?
There is no single perfect number. The classic formulas below estimate an ideal body weight from your height and sex, and they typically fall within a few kilograms of each other. A healthy weight is better thought of as a range than a single figure.
How do you calculate ideal body weight?
The most common method is the Devine formula: start from 50 kg for men or 45.5 kg for women at 5 feet tall, then add 2.3 kg for every inch of height above that. This calculator runs Devine alongside four other equations (Robinson, Miller, Hamwi and the modern Peterson) and averages them, since no single formula is definitive.
Why do the formulas give different answers?
Each was developed at a different time for a different purpose (originally for medication dosing), so they use slightly different baselines. Showing all five — plus the healthy BMI range — gives you a realistic band rather than a false-precision single number.
Do these formulas account for muscle or body type?
No. They use only height and sex, so a muscular or large-framed person may sit above their 'ideal' weight while being perfectly healthy. Pair the result with body fat percentage and how you feel, not the scale alone.
References
- Devine BJ. Gentamicin therapy (Drug Intelligence & Clinical Pharmacy, 1974) — original ideal body weight formula
- Peterson CM, et al. Universal equation for estimating ideal body weight (Am J Clin Nutr, 2016)
- World Health Organization — Body mass index (BMI)
- Robinson JD, et al. Determination of ideal body weight for drug dosage calculations (Am J Hosp Pharm, 1983)