Ideal Body Weight Calculator

Find your ideal weight range based on height and sex using four medically recognised formulas — Hamwi, Devine, Robinson, and Miller.

Unit System

Metric (cm) Imperial (ft/in)

Biological Sex

Male Female

Height (cm)

Ideal Weight Results

Enter your height and click Calculate.

About the Ideal Body Weight Formulas

Formula	Year	Originally Designed For
Hamwi	1964	Clinical nutrition — used by dietitians and hospitals
Devine	1974	Dosing medications based on body weight in clinical settings
Robinson	1983	Revision of Devine formula for drug dosing
Miller	1983	Lighter ideal weights, especially for women

Frequently Asked Questions

Ideal body weight (IBW) is an estimate of the most favourable weight for a given height, originally developed for clinical drug dosing and nutritional planning. It is not a strict target — it is a reference point. A healthy weight range based on BMI (18.5–24.9) is often more practical for most people.

Each formula was developed in a different decade and for a different clinical purpose. They use slightly different base weights and per-inch increments. The differences are usually small (2–4 kg). The range across all four formulas represents the realistic target zone.

IBW formulas are rough guides. For practical weight management, focus on staying within the BMI 18.5–24.9 range. Athletes or muscular individuals may be above IBW while still healthy. Always consult a doctor or dietitian for personalised targets.

The Hamwi formula (1964) was designed for clinical drug dosing and uses 48 kg as the male base weight at 5 feet, adding 2.7 kg per inch above. The Devine formula (1974) uses 50 kg base for males with 2.3 kg per inch, and was developed for pharmacokinetics. Both yield similar results, typically within 2–4 kg of each other. Neither was intended as a fitness goal — they are reference points used in medicine and nutrition planning.

People of the same height can have significantly different bone and frame sizes. A large-framed person has wider hips, broader shoulders, and denser bones, meaning they naturally carry more weight while still being healthy. Frame size can be estimated by measuring wrist circumference — for example, a woman with a wrist over 16.5 cm is considered large-framed. Most IBW formulas do not account for frame size, which is a key limitation. A range (rather than a single number) is a more practical target.

Ideal body weight formulas and BMI both use height and weight, but they produce different outputs. IBW formulas give a single target weight, while BMI gives a category based on a range. A BMI of 18.5–24.9 defines a healthy weight range that tends to be wider and more inclusive than IBW targets. For most people, staying within the BMI healthy range is more practical than hitting an exact IBW figure. Consult a healthcare professional for a personalised assessment.

Standard IBW formulas are not well-suited for athletes, as they do not account for lean muscle mass. A competitive bodybuilder or rugby player may weigh 10–20 kg above their calculated IBW while maintaining excellent health and very low body fat. For athletes, body fat percentage and performance metrics are far more relevant than ideal weight formulas. Consult a sports dietitian for athlete-specific body composition targets.

No single weight is universally "ideal" for a given height because body composition, genetics, age, and lifestyle all vary. A healthy weight range (derived from BMI 18.5–24.9) acknowledges this variation and gives a realistic band within which most people can maintain good health. For a person 170 cm tall, this is approximately 53.5–72 kg. Fixating on a single target number can lead to unrealistic expectations; focusing on overall fitness, energy levels, and health markers is usually more productive.

Men and women of the same height differ in average body composition — men typically have more muscle mass and denser bone, while women naturally carry a higher percentage of body fat (essential fat is 2–5% for men vs. 10–13% for women). As a result, IBW formulas use different base weights and increments for each sex to account for these physiological differences. This means the ideal weight for a 170 cm woman is typically 5–7 kg lower than for a 170 cm man using standard formulas.

Ideal weight formulas were developed decades ago for specific clinical uses such as drug dosing, not as fitness or wellness targets. They do not account for age (older adults naturally carry more fat), ethnicity (metabolic risk varies across populations), muscle mass, or frame size. As a result, the formulas can be misleading for athletes, older adults, and people from non-Western backgrounds. Use IBW as a rough reference only and consult a healthcare professional or dietitian for personalised advice.

About This Ideal Weight Calculator

This free ideal weight calculator estimates a healthy target weight range for your height using four established formulas: Devine, Robinson, Miller, and Hamwi. Results are shown for both men and women so you can compare across formulas.

No single formula defines the "ideal" weight — the range across formulas gives a practical target zone. These estimates work best as a starting reference alongside BMI, body fat percentage, and professional medical guidance.

When to use this calculator

Setting a realistic long-term weight goal
Comparing multiple ideal-weight formulas side by side
Understanding how height affects healthy weight range
Tracking progress toward a target weight

Standards & References

Wikipedia — Ideal Body Weight (Devine Formula)

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