Find your ideal body weight using five different medical formulas based on your height and gender.
Ideal Weight Results
About Ideal Weight Calculator â Ideal Weight Calculator Online
The Oneyfy ideal weight calculator online estimates your ideal body weight using four widely cited clinical formulas â Hamwi, Devine, Robinson, and Miller â plus the healthy BMI weight range (BMI 18.5 to 24.9). Enter your height and gender in either imperial or metric units and the tool instantly shows you all five estimates side by side, along with an average of the four formula results. No single formula is universally agreed upon as definitive, which is why seeing the full range is more useful than relying on any one number.
People use an ideal weight calculator online for many different reasons. Fitness beginners setting an initial weight goal want a reference point to aim for. Athletes monitoring lean body mass use these numbers alongside actual body composition measurements. Healthcare students learning pharmacokinetics study Devine and Hamwi formulas because they are used to calculate medication dosing for certain drugs. Dietitians and personal trainers reference these estimates during consultations. Regardless of your reason, understanding the range of ideal weight estimates helps you set realistic, health-focused goals rather than arbitrary numbers.
How to Use the Ideal Weight Calculator
Select your Gender using the Male or Female radio button. The formulas produce different results for males and females because they were calibrated to different baseline weight values in each group.
Select your Unit System â Imperial (feet and inches) or Metric (centimeters). The input fields change based on your selection.
Enter your Height. For Imperial, enter feet in the first field and inches in the second (for example, 5 feet and 9 inches for a 5'9" person). For Metric, enter your height in centimeters (for example, 175 cm).
Click Calculate Ideal Weight. The results panel opens showing the result from each formula in both kilograms and pounds, the healthy BMI weight range, and the average of the four formula estimates.
Review the range of estimates. The spread between formulas gives you a sense of how much individual variation exists in the concept of "ideal weight."
The Four Formulas Explained
Each formula was developed in a different decade by different researchers, and each reflects slightly different assumptions about healthy body weight relative to height.
Hamwi (1964): Originally developed for clinical drug dosing. Males: 48 kg base + 2.7 kg per inch over 5 feet. Females: 45.5 kg base + 2.2 kg per inch over 5 feet. This formula tends to produce lower estimates and is commonly taught in nursing and pharmacy programs.
Devine (1974): The most widely cited formula in clinical practice and pharmacokinetics research. Males: 50 kg + 2.3 kg per inch over 5 feet. Females: 45.5 kg + 2.3 kg per inch over 5 feet. Many medication dosing protocols reference the Devine formula specifically.
Robinson (1983): A revision of Devine designed to better reflect lean body mass. Males: 52 kg + 1.9 kg per inch over 5 feet. Females: 49 kg + 1.7 kg per inch over 5 feet. The smaller increment per inch produces a narrower weight range for taller individuals.
Miller (1983): Another revision of Devine, producing the highest estimates of the four formulas for most heights. Males: 56.2 kg + 1.41 kg per inch over 5 feet. Females: 53.1 kg + 1.36 kg per inch over 5 feet. The higher base weight and lower per-inch increment make Miller estimates more generous for taller heights.
Tips for Getting the Best Results
Understanding the context and limitations of ideal weight formulas helps you use the results appropriately.
Use the range, not a single number: The four formulas typically produce estimates within a 5â10 kg range of each other. Rather than targeting one specific number, use the range as a guideline. Falling within the range â and especially within the BMI 18.5â24.9 window â is a more practical health goal than hitting one formula's exact figure.
Consider body composition, not just weight: These formulas estimate ideal weight from height alone. They do not account for muscle mass, bone density, body fat percentage, or frame size. A muscular athlete may weigh significantly above the formula estimate while still being in excellent health. Always interpret these numbers in the context of your actual body composition.
Check both imperial and metric results: The tool displays results in both kilograms and pounds regardless of which unit system you selected, so you can reference whichever unit you are more comfortable thinking in without switching modes.
Use the BMI range for the most current clinical reference: Among all the options shown, the healthy BMI weight range (18.5â24.9) is the figure most commonly used in current clinical guidelines. The Hamwi and Devine formulas are older and were developed for specific clinical purposes; BMI-based ranges reflect more recent population research.
Consult a healthcare professional for medical decisions: Ideal weight formulas are useful reference points but should not drive medical or dietary decisions alone. A doctor, dietitian, or certified fitness professional can assess your actual health status and set individualized targets that these formulas cannot account for.
Why Use an Ideal Weight Calculator Online
Calculating Hamwi, Devine, Robinson, and Miller ideal weights by hand requires knowing the formula for each, doing unit conversions from height to inches-over-five-feet, and running four separate calculations. An ideal weight calculator online does all of that instantly for both genders and both unit systems. There is no installation, no account, and your height data never leaves your browser.
Students studying pharmacology or nursing who need to practice ideal weight calculations for drug dosing, fitness enthusiasts setting initial weight goals, and anyone curious about how different research-based formulas compare all get fast, accurate results from a single entry.
Frequently Asked Questions about Ideal Weight Calculator
No single formula is universally the most accurate for all people. Each was derived from different populations and different research contexts in the 1960s and 1980s. In current clinical practice, the healthy BMI range (18.5â24.9) is the most widely used guideline for assessing weight relative to health risk. The Devine formula is the most commonly referenced in pharmacokinetics for drug dosing calculations. For general health goals, treat all five estimates as a reasonable range rather than precise targets.
These formulas were originally developed for clinical drug dosing in hospital settings, where a fast height-based estimate of lean body mass was needed to calculate appropriate medication doses. Height was easy to measure quickly and correlated reasonably well with lean mass. The formulas do not account for body frame size, muscle mass, age, or body fat percentage â factors that matter more for fitness and nutrition goals than for drug dosing calculations.
Not exactly. The BMI healthy weight range (18.5â24.9) represents a statistical correlation between weight and reduced risk for certain health conditions based on population studies. The formula-based "ideal weight" estimates are clinical approximations of lean body mass, not wellness targets. Individual healthy weight depends on body composition, age, genetics, frame size, and health history â all of which these formulas do not capture. A doctor or dietitian can help you determine a truly personalized healthy weight target.
Yes, completely free. There is no sign-up, no account, and no limits on how many times you calculate. The tool is available in your browser at no cost any time you need it.
No. All calculations run entirely in your browser using JavaScript. Your height, gender, and unit inputs are never transmitted to any server. Your data stays private on your device throughout your session.
Yes. The ideal weight calculator is fully responsive and works on any modern smartphone or tablet browser. The radio buttons and number inputs are touch-friendly, and the results panel displays clearly on small screens.
The average ideal weight shown is the arithmetic mean of the four formula results (Hamwi, Devine, Robinson, and Miller). It does not include the BMI range values. The average provides a single mid-point estimate that balances the different assumptions of each formula and can serve as a practical reference point if you want one number rather than a range.
Each formula uses a different base weight and a different per-inch increment, reflecting different research assumptions about what constitutes a healthy or appropriate lean body weight. For a male at 5'9", the results typically range from about 68 kg (Hamwi) to around 73 kg (Miller) â a spread of roughly 5 kg. The differences become larger at greater heights because the per-inch increments compound across more inches over the 5-foot base.