Ideal Weight Calculator - Free Online Ideal Body Weight Calculator
Calculate your ideal body weight using four established medical formulas: Robinson, Miller, Devine, and Hamwi. Compare results across all methods to find your healthy target weight range.
About This Tool
Determining your ideal body weight can help you set realistic health and fitness goals, guide nutritional planning, and provide a reference point for monitoring your progress. Our free ideal weight calculator uses four well-established medical formulas -- Robinson (1983), Miller (1983), Devine (1974), and Hamwi (1964) -- to generate a range of ideal weight estimates based on your height and gender. Rather than relying on a single number, the calculator presents results from all four methods along with their average, giving you a more balanced perspective.
Each formula was developed through clinical research and takes a slightly different approach to estimating ideal weight. The Devine formula is one of the most widely used in clinical settings, originally created for calculating medication dosages. The Hamwi formula is popular in clinical nutrition for establishing baseline dietary goals. The Robinson and Miller formulas were developed as refinements to earlier methods, offering updated coefficients based on more recent population data.
It is essential to recognize that "ideal weight" is not an absolute number. These formulas provide reference points based on population averages, but they do not account for individual factors such as muscle mass, bone density, body frame size, or ethnic background. A person with significant muscle development may weigh more than the calculated ideal without being overweight. Similarly, someone with a smaller frame may have a lower ideal weight than these formulas suggest.
These results are best used as a general guideline rather than a strict target. For a complete picture of your health, consider your ideal weight alongside other metrics such as BMI, body fat percentage, and waist-to-hip ratio. Consult your healthcare provider or a registered dietitian for personalized weight management advice that considers your full medical history and individual circumstances.
Key Features
- Calculates ideal weight using four clinically established formulas for a comprehensive view
- Displays the average across all four methods for a balanced reference point
- Side-by-side comparison table showing results from Robinson, Miller, Devine, and Hamwi formulas
- Supports both imperial (inches/lbs) and metric (cm/kg) measurements
- Gender-specific calculations reflecting physiological differences in body composition
Frequently Asked Questions
Why do the four formulas give different ideal weight results?
Each formula was developed using different study populations, time periods, and statistical methods. The Devine formula (1974) and Hamwi formula (1964) are older and were based on earlier population data, while Robinson and Miller (both 1983) represent updated calculations. The variation between formulas reflects the inherent difficulty in defining a single ideal weight, which is why viewing the range and average provides a more useful picture than any single number.
Is my ideal weight the same as my healthiest weight?
Not necessarily. Ideal weight formulas provide a statistical reference based on height and gender, but they do not consider muscle mass, bone structure, body fat distribution, or individual health markers. Your healthiest weight is one where your blood pressure, blood sugar, cholesterol, and other vital signs are within normal ranges, and you feel energized and capable. Work with your healthcare provider to determine what weight range is best for your specific health profile.
Do these formulas work for people under 5 feet tall?
These formulas were designed for adults who are at least 5 feet (60 inches or 152.4 cm) tall. For individuals shorter than this threshold, the mathematical calculations become unreliable and may produce inaccurate results. If you are under 5 feet tall, consult your healthcare provider for appropriate weight guidelines based on your specific body measurements and health needs.