Ideal Body Weight Calculator

Healthy Weight Range (BMI 18.5–24.9): --

What Is Ideal Body Weight?

Ideal Body Weight (IBW) refers to the weight at which an individual is predicted to have the best health outcomes based on their height and sex. IBW formulas were originally developed in clinical medicine to estimate drug dosages and ventilator settings, but they have since become widely used as health reference points.

The Four Main IBW Formulas

  • Devine Formula (1974): The most widely used formula, originally developed for drug dosing in clinical pharmacology. It is the standard in many medical settings.
  • Robinson Formula (1983): A refinement of Devine's work, generally considered slightly more accurate for taller individuals.
  • Miller Formula (1983): Published in the same year as Robinson's; tends to give slightly higher weights, especially for taller people.
  • Hamwi Formula (1964): One of the oldest dietitian-derived formulas, commonly taught in nutrition education.

IBW vs BMI Weight Range

The BMI-based healthy weight range (BMI 18.5–24.9) gives a broader target, while IBW formulas give a single point estimate. The BMI range is often more practical for goal-setting because it acknowledges natural variation in body build. Using both metrics together gives a more complete picture.

Limitations of Ideal Body Weight

IBW formulas were developed primarily for white, Western populations and may not accurately represent ideal weight for people of Asian, African, or other ethnic backgrounds. They also do not account for age, muscle mass, or body frame size. They should be used as general guides, not hard targets.

Frequently Asked Questions

Which IBW formula is most accurate?
No single formula is universally most accurate. The Devine formula is the most widely used clinically, but the Robinson formula is generally considered slightly more accurate for moderately tall adults. Using the average of all four gives a reasonable range.
Should I try to reach my IBW?
IBW is a reference point, not a strict target. Falling anywhere within the BMI 18.5–24.9 healthy weight range is generally considered healthy. Athletic individuals with high muscle mass may have a healthy weight above their calculated IBW.
Do IBW formulas work for short people?
IBW formulas can give unrealistically low values for people under 5 feet (152 cm) tall. For very short or very tall individuals, the BMI-based healthy weight range is often a more practical reference.
Is there an ideal weight for different body frames?
Yes. Some clinicians adjust IBW by ±10% for small or large frame sizes. Frame size can be estimated by measuring wrist circumference or elbow breadth relative to height.