Free Ideal Body Weight Calculator - Multiple Formulas

Based on peer-reviewed medical formulas. See our formulas & sources ?

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What Is Ideal Body Weight?

Ideal body weight depends on your height, gender, and body frame. Our calculator averages four validated formulas — Hamwi (1964), Devine (1974), Robinson (1983), and Miller (1983) — to provide a personalized ideal weight range. These formulas were originally developed for estimating drug dosages but are now widely used as quick reference points for healthy weight ranges.

Ideal body weight (IBW) is a target weight range that is generally considered healthy for a given height and gender. The concept dates back to the mid-20th century when physicians needed a quick reference for drug dosing and clinical assessments. Several formulas were developed, each using height as the primary variable. These formulas provide a useful estimate, but they are just one piece of the puzzle. Your ideal weight also depends on your body composition, frame size, muscle mass, age, and overall health — none of which a simple height-based calculation can fully capture.

How These Formulas Work

All four formulas used in this calculator were developed in the 1970s and 1980s for different clinical and research purposes:

Hamwi (1964) — Originally developed for dietary planning. Uses inches for height and provides a simple baseline starting at 48 kg for men and 45.5 kg for women.
Devine (1974) — Created to estimate ideal body weight for drug dosing. Uses centimeters directly and adjusts from a reference height of 152.4 cm (5'0").
Robinson (1983) — Based on insurance data from the Metropolitan Life Insurance Company. Uses inches and has slightly different starting points for men (52 kg) and women (49 kg).
Miller (1983) — Developed for clinical use with a focus on maintaining a healthy weight range. Uses inches with a higher baseline for men (56.2 kg) and women (53.1 kg).

This calculator shows each formula's result so you can see the range and choose what makes sense for you.

Formulas: Hamwi (1964), Devine (1974), Robinson (1983), Miller (1983). Full methodology ?

Why One Number Isn't Enough

Ideal weight formulas only use height and gender. They don't account for factors that significantly affect what a healthy weight actually looks like for you:

Body composition — Two people at the same weight can have very different ratios of muscle to fat. Muscle is denser than fat, so a muscular person will weigh more at the same size.
Frame size — People with larger bone structures naturally weigh more. A formula can't tell if you have narrow or broad shoulders.
Muscle mass — Athletes and regular exercisers carry more muscle, which adds weight without adding health risk.
Age — Metabolism slows and body composition shifts with age. A weight that was ideal at 25 may not be the same at 55.

Use the formulas as a starting point, not a strict target.

Beyond the Numbers

The best measure of a healthy weight isn't a formula — it's how your body feels and functions. Focus on these health markers instead:

Energy levels — Do you feel energized throughout the day without excessive fatigue?
Blood pressure and cholesterol — Regular check-ups can tell you if your weight is affecting cardiovascular health.
Waist circumference — Abdominal fat is a stronger predictor of health risk than total weight. Men should aim for under 94 cm, women under 80 cm.
Physical performance — Can you move freely, exercise comfortably, and perform daily tasks without difficulty?
Sleep quality — Healthy weight supports better sleep, and better sleep supports a healthy weight.

Our Body Fat Calculator and BMI Calculator can give you additional perspectives on your weight status.

Frequently Asked Questions

What is the most accurate ideal weight formula?

No single formula is considered the most accurate for everyone. Each formula (Hamwi, Devine, Robinson, Miller) was developed for different populations and clinical purposes. The Hamwi formula was created for dietary use, Devine for medication dosing, Robinson for insurance data, and Miller for clinical settings. The average of all four gives the best general estimate.

Do these formulas work for all body types?

These formulas are based solely on height and gender. They do not account for frame size, muscle mass, body composition, age, or ethnicity. A muscular person or someone with a larger frame may weigh more than their calculated ideal weight and still be perfectly healthy.

What if I weigh more than my ideal weight?

Weighing more than your calculated ideal weight is not necessarily unhealthy. Muscle is denser than fat, so athletes and active individuals often weigh more. Focus on body composition, energy levels, and health markers rather than a single number on the scale.

Are these formulas different for children?

Yes, these formulas are designed for adults only. Children and adolescents use age-based growth charts (CDC or WHO percentiles) to assess healthy weight, as their bodies are still developing and growth patterns vary significantly by age.

How does age affect ideal weight?

These formulas do not account for age. In reality, metabolism slows with age, muscle mass tends to decrease, and body composition changes. Older adults may need to focus more on maintaining muscle mass than hitting a specific weight target.

Should I aim for the middle of the range?

Yes, the average of the four formulas is generally a good target. It balances out the differences between each formula's assumptions. However, the best weight for you is one where you feel healthy, have good energy, and your health markers are in a good range.

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Body Fat Calculator — Estimate body fat percentage

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Ideal Weight Calculator