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Ideal Weight Calculator

Ideal body weight by height and sex, four proven formulas.

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How to use

  1. 1.Choose your sex, then pick a height unit — centimeters, inches, or feet plus inches.
  2. 2.Type your height; in feet-plus-inches mode fill in both the feet and the inches box.
  3. 3.Read your ideal weight from all four formulas, their average, and the healthy BMI range below — it updates instantly, in both kg and lb.

About Ideal Weight Calculator

This ideal weight calculator turns your height and sex into an ideal body weight the moment you type — there is no button to press and nothing is uploaded. It reports four classic formulas side by side (Devine, Robinson, Miller and Hamwi), their average, and a healthy weight range based on the standard body mass index (BMI) band, each shown in both kilograms and pounds so you can read whichever unit you prefer.

The reason four numbers appear instead of one is that there is no single agreed 'ideal' weight — each formula is a different expert's line of best fit. Every one of them works the same way: a base weight for a person exactly 5 feet (152 cm) tall, plus a fixed amount for each inch above that. Hamwi (1964) was created by Dr. G.J. Hamwi to help estimate nutrition needs and gives the highest figures. Devine (1974), by Dr. B.J. Devine, was originally built to calculate medication doses and has become the most widely quoted formula in medicine. Robinson (1983) and Miller (1983) reworked Devine's numbers against fresh data and generally sit a little lower. Because their slopes and starting points differ, a tall person sees a wider spread between the formulas than a short person does.

The healthy weight range shown alongside them is not a formula at all but a BMI band. BMI is weight divided by height squared, and health bodies such as the WHO treat 18.5 to 25 as the normal range. Multiplying each end of that band by your height in metres squared converts it into an actual weight range, which is often the most useful figure here: it is a range rather than a single target, and it is grounded in population health data rather than a mid-20th-century rule of thumb.

A few limits are worth knowing. These formulas only take height and sex, so they cannot see muscle, bone or frame size — a lean, muscular athlete can weigh well above their 'ideal' number and still be perfectly healthy, while the reverse can also be true. The formulas are calibrated for adults of 5 feet and taller; below that height they collapse to their baseline value and stop being meaningful, so this tool flags that and points you to the BMI range instead. They also assume a binary male or female input and do not apply to children. Treat the result as a rough, informational estimate, not a diagnosis or a target set by a professional. To explore other body measurements, pair it with a bra size calculator, a clothing size converter, or an age calculator.

Frequently asked questions

How is ideal body weight calculated?
Each formula starts from a base weight for a person 5 feet (152 cm) tall and adds a set amount for every inch above that. For a male, Devine (1974) uses 50 kg + 2.3 kg per inch over 5 ft, Robinson (1983) 52 kg + 1.9 kg, Miller (1983) 56.2 kg + 1.41 kg, and Hamwi (1964) 48 kg + 2.7 kg. Female versions use lower base weights. So a 175 cm (5 ft 9 in) man is about 8.9 inches over 5 ft, giving a Devine ideal of 50 + 2.3 × 8.9 ≈ 70.5 kg.
Which formula should I use, and why do they differ?
There is no single 'correct' one — each is a different researcher's estimate fitted to different data. Hamwi tends to give the highest number and Miller among the lowest, with Devine and Robinson in between. Devine is the most cited in clinical settings. Rather than pick one, look at the average and the healthy BMI range together to see the sensible band your weight could fall in.
What is a healthy weight range for my height?
The range this tool shows comes from body mass index (BMI): the WHO treats a BMI of 18.5 to 25 as the normal band. Multiplying each end by your height in metres squared gives a weight range. For example, at 175 cm (1.75 m) that is 18.5 × 1.75² ≈ 56.7 kg up to 25 × 1.75² ≈ 76.6 kg. This range is usually more informative than any single 'ideal' number.
Does it account for muscle or body frame?
No. These formulas use only height and sex, so they cannot tell muscle from fat or a small frame from a large one. A muscular athlete can sit above their 'ideal' weight and still be healthy, while someone with a very light frame may be comfortable below it. Use the result as a reference point, not a hard target, and consider frame size and body composition separately.
Is this medical advice?
No. This calculator is for general information only and is a rough estimate based on height and sex alone. It does not account for age, muscle mass, frame, ethnicity or medical history, and it is not suitable for children. It is not a diagnosis or a treatment recommendation — for guidance on a healthy weight for you, speak with a doctor or a registered dietitian.

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