Ideal weight calculator

How ideal weight is calculated

Ideal weight formulas were originally developed for medical purposes — to estimate doses, screen for obesity risk and provide simple population-level reference points. Each formula uses height as the primary input, with different adjustments for gender and body frame. None of them directly measure body composition, but together they give a useful ballpark for most people.

This calculator shows you four different formulas side by side, plus a healthy BMI range for your height. Discrepancies between formulas are normal — treat the range across all methods as your healthy zone rather than fixating on any single number.

Different formulas explained

• Devine formula (1974): Originally developed to calculate drug dosages. Male: 50 kg + 2.3 kg per inch over 5 ft. Female: 45.5 kg + 2.3 kg per inch over 5 ft.
• Robinson formula (1983): A revision of Devine, intended to better reflect desirable body weight. Male: 52 kg + 1.9 kg per inch over 5 ft. Female: 49 kg + 1.7 kg per inch over 5 ft.
• Miller formula (1983): Developed using more recent data, producing slightly lower weights. Male: 56.2 kg + 1.41 kg per inch over 5 ft. Female: 53.1 kg + 1.36 kg per inch over 5 ft.
• Hamwi formula (1964): One of the earliest formulas, still used in some clinical settings. Male: 48 kg + 2.7 kg per inch over 5 ft. Female: 45.5 kg + 2.2 kg per inch over 5 ft.

Limitations of ideal weight

These formulas have significant limitations that are important to understand. They do not account for muscle mass, so a muscular person may be classified as over "ideal" weight while having a healthy body composition. None adjust for age, ethnicity, bone density or where you carry your weight. They were developed on specific populations decades ago and may not translate well to everyone.

For a more complete picture, combine this calculator with our BMI calculator and body fat calculator. The truth is that a healthy weight for you is one where you feel energetic, strong and well — focus on habits over numbers.

Frequently asked questions

What is my ideal weight?

It depends on your height, gender and body frame. The four formulas above give a range; the healthy BMI range (18.5–24.9) gives another. Speak to a doctor for personalised guidance.

How accurate are these formulas?

They are rough population-level estimates, not personalised targets. They do not account for muscle, bone density or age. Use the range across all methods as a guide.

What's a healthy BMI range?

A BMI of 18.5–24.9 is the healthy range for most adults per the WHO, CDC and NHS. This translates to a weight range you can see in the results above.

Which formula should I use?

There is no single "best" formula. The Devine formula is still used for medical dosing, while Miller is often cited in weight-loss studies. Look at all four as a range of plausible healthy weights for your height.

This tool is for information only and is not medical advice. Consult a health professional about your weight or health.