What is Ideal Weight?
Ideal weight is a theoretical weight that is considered healthiest for a person of a certain height and gender. There is no single correct way to determine ideal weight, which is why this calculator uses three widely accepted formulas to provide a broader perspective.
How to Use
Enter your gender and height in centimeters. The calculator provides three different estimates of your ideal weight, as well as their average. You will also see an estimated ideal weight range.
Formulas
The calculator uses the following formulas (height in inches, 1 inch = 2.54 cm):
Devine (1974)
This is the most commonly used formula in medical contexts, such as drug dosing.
- Men: 50 kg + 2.3 kg for every inch over 5 feet
- Women: 45.5 kg + 2.3 kg for every inch over 5 feet
Robinson (1983)
Developed to improve upon the Devine formula based on newer data.
- Men: 52 kg + 1.9 kg for every inch over 5 feet
- Women: 49 kg + 1.7 kg for every inch over 5 feet
Hamwi (1964)
Often used in diabetes care and nutritional planning.
- Men: 48 kg + 2.7 kg for every inch over 5 feet
- Women: 45.5 kg + 2.2 kg for every inch over 5 feet
Interpreting the Results
Different formulas yield slightly different results, which is normal. Ideal weight is not a single precise number, but rather a range.
- Devine: Often the standard in medicine.
- Robinson: May give slightly higher values for men and lower for women compared to Devine.
- Hamwi: Often gives slightly lower values, especially for women.
Example
A man who is 180 cm tall (approx. 71 inches):
- Height is 11 inches over 5 feet (60 inches).
- Devine: 50 + (2.3 * 11) = 75.3 kg
- Robinson: 52 + (1.9 * 11) = 72.9 kg
- Hamwi: 48 + (2.7 * 11) = 77.7 kg
In this case, the ideal weight would fall between approximately 73–78 kg.
Limitations
These formulas were originally developed for drug dosing and do not account for body frame, muscle mass, or age. They are best suited for adults with an average build. For athletes or very muscular individuals, Body Mass Index (BMI) or body fat percentage may provide a better indication of health.
Practical review checklist
Use the Ideal Weight Calculator result as a planning number, then compare it with at least two nearby scenarios. A single calculation is useful, but the decision usually becomes clearer when you also test a conservative value and an optimistic value. Change one input at a time so you can see which assumption has the strongest effect. This is especially helpful when the inputs come from estimates, rounded measurements, future dates, or prices that may change before you act.
Before relying on the result, check that every unit matches the label in the form. Percent fields normally expect a percentage such as 5 rather than 0.05, date fields should use the actual calendar date, and money fields should be entered without currency symbols. If the result looks surprising, return to the inputs first. Most unexpected outputs come from a misplaced decimal, a mixed unit, or a value copied from another source with different rounding.
For important financial, health, building, laboratory, or engineering choices, treat the calculator as a transparent first pass. It helps you understand direction and scale, but it does not replace local rules, professional review, manufacturer tolerances, medical guidance, or your own measured data. Save the assumptions you used when comparing alternatives so later decisions are based on the same baseline.