Ideal Weight Calculator

Target weight from four clinical formulas plus BMI range.

Calculate ideal body weight using the Devine, Robinson, Miller, and Hamwi formulas, alongside the healthy BMI range for your height and frame size.

Written and maintained by Mohit PatelLast checked August 4, 2026How we build these

Units

Sex

Height

Current weight

Optional, used to show the gap to your target.

Body frame

Wrap your thumb and index finger around the opposite wrist: overlapping means small, touching means medium, not meeting means large.

These formulas were built for clinical dosing, not body composition. They ignore muscle mass entirely, so athletes will read as overweight. Treat the range as a guide, not a goal.

Ideal weight

70.0 kg

range 69 kg – 72 kg

Healthy BMI range57 kg – 76 kg

Current weight70.0 kg

Below average target0.0 kg

Formula comparison

Formula	Notes	Ideal weight
Devine (1974)	Clinical standard, used for drug dosing.	70.5 kg
Robinson (1983)	A revision of Devine; lower for taller people.	68.9 kg
Miller (1983)	Flattest curve; highest at short heights.	68.7 kg
Hamwi (1964)	The oldest; steepest increase with height.	72.0 kg

How the Ideal Weight Calculator works

There is no single correct ideal weight, so this calculator shows four established clinical formulas side by side along with the healthy BMI range. Treat the spread between them as the realistic target zone rather than chasing one exact number.

Also known as: healthy weight range · Devine formula weight · what should I weigh

The formulas and what they were for

Devine, published in 1974, gives 50 kilograms plus 2.3 per inch over five feet for men, and 45.5 plus 2.3 for women. It was written as a drug dosing tool, not as a health target, which its name has obscured ever since.

Robinson and Miller, both from 1983, adjusted the constants. Hamwi, from 1964, is similar and predates all of them.

None of these was derived from outcome data linking weight to health. They are conventions that produce a plausible number from a height, and they were adopted for clinical convenience rather than because they identify an optimum.

Why the concept is questionable

There is no single ideal weight for a given height. Body composition, frame size, age, muscle mass and individual metabolic health all matter, and none of them appears in any of the formulas.

The formulas also produce noticeably different answers. For a 5 foot 10 man, Devine gives 73 kilograms, Robinson 70.5, Miller 70.8 and Hamwi 75.7. A spread of five kilograms between equations claiming to identify the ideal suggests the concept is doing less work than the name implies.

A healthy weight range is a more defensible framing than a point. The BMI healthy range for that height spans roughly 58 to 78 kilograms, and people are healthy across it.

Where these numbers are actually used

Drug dosing is the genuine clinical application, particularly for drugs distributing into lean tissue rather than fat. Some anaesthetic agents, some antibiotics and mechanical ventilation tidal volumes all use predicted or ideal body weight.

Ventilator tidal volume is the most important of those, since lung volume scales with height rather than with actual weight, and using actual weight in an obese patient delivers dangerously large volumes.

That is the context these formulas were written for, and it is one where a convention that is roughly right and consistently applied is more useful than a debate about what anyone should weigh.

A better question

Rather than what should I weigh, the more answerable questions are whether current weight is associated with health problems, whether waist circumference is in a healthy range, and whether metabolic markers are normal.

The health benefits of weight loss for someone carrying excess weight accrue substantially before any particular target: 5% to 10% of starting weight produces measurable improvements in blood pressure, glucose control and lipids.

That is a far more achievable objective than a specific figure, and it is what most of the outcome evidence actually supports. Pursuing an ideal weight from a 1974 dosing formula is pursuing a number that was never about health.

When a target does more harm

For anyone with a history of disordered eating, a prescribed target weight can be actively harmful, and weight-focused goals are avoided in most eating disorder treatment for that reason.

Athletes in weight-category sports face a version of the same problem, and rapid weight manipulation to make a category carries documented risks.

Anyone finding that a number on a scale is affecting their eating, their mood or their relationship with food should speak to a clinician. That is not a caveat added for form; weight-focused goal setting is a recognised contributor to eating disorders, and a calculator cannot tell who is at risk.

Where to go next

The Ideal Weight question rarely arrives on its own. These are the ones that usually come with it:

BMI Calculator — Body mass index with category and healthy weight range.
Body Fat Calculator — Body fat percentage from tape measurements.
Calorie & BMR Calculator — Daily calorie needs for losing, holding, or gaining weight.
VDOT Running Calculator — One race result, every training pace.

Sources

Not medical advice. This calculator gives a general estimate, not medical advice. It cannot account for your individual health, medical history, or medication. Talk to a qualified healthcare professional before acting on any result.

Frequently asked questions

Which ideal weight formula should I use?

Devine is the most widely used in clinical settings, originally for drug dosing. Robinson and Miller give slightly lower figures and fit smaller frames better. Rather than picking one, use the range they produce together, the healthy BMI range is usually the most practical target.

Does frame size matter?

Yes, by roughly 10%. Measure your wrist circumference: relative to height, a smaller wrist indicates a small frame and a target near the lower end of the range, a larger wrist the opposite. This calculator adjusts for the frame size you select.

Do these formulas work for athletes?

Poorly. They are height-based and ignore muscle mass entirely, so a trained athlete will often read as overweight. If you carry significant muscle, body fat percentage is a far more meaningful target than scale weight.

Is ideal weight different for men and women?

Yes. All four formulas start from a different base weight at 5 feet for men and women, typically 2-4 kg lower for women, then add a fixed amount per additional inch of height.