Body & Weight

Ideal Weight Calculator

There is no single perfect number on the scale, but you can find a sensible target range. This tool shows the healthy weight range for your height using BMI, plus a single figure from the clinical Devine formula.

Calculate your ideal weight

Sex

Used because the formula differs for men and women.

cm
Healthy weight range (BMI 18.5–24.9)56.7 kg – 76.3 kg
45 kgHealthy: 56.7–76.3 kg88 kg
Devine formula ideal weight
70.5 kg

There is no single "ideal" weight. A healthy BMI range and the Devine clinical formula give complementary targets.

This is an educational estimate, not medical advice. Consult a qualified professional.

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Two ways to estimate ideal weight

The first method is BMI-based. A healthy BMI is 18.5–24.9, so the healthy weight range is simply 18.5 × height (m)² to 24.9 × height (m)². This gives a realistic band rather than one rigid figure, which better reflects how healthy bodies actually vary.

The second is the Devine formula, created in the 1970s to standardise medication dosing. For men it is 50 kg + 2.3 kg for every inch over 5 feet; for women, 45.5 kg + 2.3 kg per inch over 5 feet. It returns a single reference weight and is still used in clinical settings, though it tends to under-estimate for very tall or very short people.

Which number should you use?

Treat the BMI range as your everyday target — anywhere inside it is reasonable for most adults. The Devine figure is useful as a quick reference point and is what many medical formulas rely on, but it was never designed as a personal fitness goal.

Neither method accounts for muscle mass, frame size or body-fat distribution. A muscular person may sit above their "ideal" weight while being very healthy. If your goal is body composition rather than a scale number, pair this with a body-fat or lean-mass estimate.

Setting a healthy goal

If your current weight is outside the healthy range, you do not need to reach the exact middle of it to benefit. Research shows that losing just 5–10% of body weight meaningfully improves blood pressure, blood sugar and cholesterol. Aim for steady, sustainable change of around 0.5–1 kg (1–2 lb) per week, and focus on habits — food quality, protein, sleep and movement — rather than a single target number.

Frequently asked questions

Is there really an "ideal" weight?

No single number is ideal for everyone of the same height. A healthy weight is best thought of as a range, which is why this tool shows the full BMI-based band alongside the Devine reference figure.

Why do the BMI range and Devine numbers differ?

They use different methods. The BMI range comes from population health data, while the Devine formula is a clinical dosing estimate. Small differences between them are normal and expected.

Does ideal weight depend on age or muscle?

These formulas use only height and sex, so they do not adjust for age, frame size or muscle mass. Athletes and older adults in particular should interpret the result alongside body-composition measures.

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Sources & references

  1. World Health Organization. "Obesity and overweight" fact sheet (BMI classification and health risks).
  2. Devine BJ. "Gentamicin therapy" (origin of the ideal body weight formula). Drug Intell Clin Pharm. 1974;8(11):650–655.