Skip to content The Robinson formula is one of several equations that estimate a reference or “ideal” body weight from height. A commonly cited version starts at 5 feet and adds 1.9 kg per inch for men or 1.7 kg per inch for women. Calculators may use converted metric values, different rounding, or another convention for heights below 5 feet. Check a tool’s stated formula rather than assuming every result is identical.
A formula is not a personal assessment
The equation uses height and a category, not a direct measurement of body fat, muscle, nutrition, or health. Its output cannot account for a person’s medical history, age-related changes, or goals. The word “ideal” can be misleading: a calculated reference is not automatically a safe or appropriate weight for an individual.
Clinical use versus self-directed goals
Healthcare professionals may encounter weight equations in a specific clinical protocol. That context is different from using an online number to decide treatment or diet. The CDC notes that BMI is a screening tool and does not distinguish fat, muscle, and bone; height-only ideal-weight equations have different assumptions and also cannot summarize health.
Do not use the Robinson result to adjust medication, diagnose a condition, or begin a restrictive plan. If you want to discuss a weight goal, a healthcare professional can consider relevant measurements and your history. For comparison, read our Hamwi equation guide and the Devine formula guide.
Common questions
Why do Robinson calculators differ?
They may use distinct coefficients, unit conversions, rounding, or rules for shorter heights.
Is the result a healthy-weight prescription?
No. A height-based formula cannot set a personalized goal.
Can I use it to calculate a medicine dose?
No. Follow the prescriber and applicable clinical protocol.
Sources
Educational information only; not a diagnosis, prescription, or individualized weight goal.
