Ideal Weight Calculator
Find your ideal body weight for your height and gender using four trusted medical formulas — Devine, Robinson, Miller and Hamwi — plus your healthy weight range based on BMI.
Calculate Your Ideal Weight
Enter your gender and height to see your ideal weight estimates in kilograms.
What Is Ideal Body Weight?
Ideal body weight (IBW) is an estimate of the weight that is generally considered healthy for a person of a given height and gender. The concept originated in medicine — doctors used it to calculate appropriate drug dosages — and it has since become a popular reference point for fitness and general health. Because IBW depends mainly on height, it offers a quick benchmark, but it should always be interpreted alongside other measures like BMI, body-fat percentage and waist circumference.
The Four Formulas Explained
This calculator presents four established formulas, each developed from different research:
- Hamwi (1964): One of the earliest, originally created for medication dosing.
- Devine (1974): The most widely used in clinical settings, especially pharmacology.
- Robinson (1983): A refinement of the Devine formula based on later data.
- Miller (1983): Another modern adjustment using updated population statistics.
All four use a base weight for a height of five feet, then add a fixed amount for every inch above that — with different constants for men and women. The small spread between them gives you a realistic range rather than a single rigid number.
Ideal Weight vs Healthy BMI Range
Alongside the formulas, this calculator shows your healthy weight range derived from the Body Mass Index. A BMI between 18.5 and 24.9 is classified as a healthy weight, so multiplying those values by the square of your height in metres gives the weight band you should aim to stay within. This range is often more useful than a single ideal figure, because it acknowledges that healthy weights naturally vary from person to person.
Worked Example
Consider a man who is 175 cm tall. That is about 68.9 inches, or 8.9 inches over five feet. Using the Devine formula, his ideal weight is 50 + 2.3 × 8.9 ≈ 70.5 kg, while the Robinson formula gives about 68.9 kg. His healthy BMI range works out to roughly 56.7 kg to 76.3 kg. Together, these tell him that a weight in the high-60s to low-70s kg is a sensible target for his height.
Limitations to Keep in Mind
Ideal weight formulas consider only height and gender — they ignore muscle mass, frame size, age and body composition. A muscular athlete may weigh well above their "ideal" figure yet carry very little fat and be extremely healthy, because muscle is denser than fat. Conversely, someone within their ideal range could still have an unhealthy body-fat distribution. Use IBW as one input among several, not as the sole judge of health.
Reaching a Healthy Weight
If your current weight sits outside the healthy range, aim for gradual, sustainable change — about 0.25 to 0.5 kg per week — through a modest calorie adjustment, regular activity and adequate protein. Avoid crash diets, which are difficult to maintain and can harm your metabolism. A calorie calculator can help you set realistic daily targets, and a doctor or registered dietitian can provide guidance tailored to your circumstances.
Note: This calculator provides general estimates for educational purposes and is not medical advice. Individual healthy weights vary with body composition, age and health conditions. Consult a healthcare professional before making significant changes to your weight or diet.
Frequently Asked Questions — Ideal Weight Calculator
Ideal body weight is an estimate of the healthy weight range for a person based primarily on their height and gender. It was originally developed in medicine to help calculate medication dosages, and is now widely used as a general fitness reference. Because it does not account for muscle mass or body composition, it is best treated as a guideline rather than an exact target.
This calculator shows four widely recognised formulas — Devine (1974), Robinson (1983), Miller (1983) and Hamwi (1964) — alongside the healthy weight range derived from a BMI of 18.5 to 24.9. Each formula uses your height and gender but with slightly different constants, so they produce a small range of values that together give a realistic target.
Each formula was developed from different population data and assumptions, so their base weights and per-inch increments vary slightly. The differences are usually only a few kilograms. Rather than fixating on one number, look at the range across all four formulas plus your healthy BMI range to identify a sensible weight band for your height.
Not exactly. Ideal weight formulas give a single estimate, while a healthy weight is better expressed as a range — typically the weights that correspond to a BMI between 18.5 and 24.9 for your height. Athletes and muscular individuals may weigh more than their "ideal" figure yet still be perfectly healthy, since muscle is denser than fat.
No. These formulas consider only height and gender, not frame size, muscle mass, age or body-fat percentage. A bodybuilder and a sedentary person of the same height share the same "ideal weight" even though their bodies are very different. For a fuller picture, combine this with body-fat measurement and waist circumference.
Aim for gradual change of about 0.25–0.5 kg per week through a modest calorie deficit (to lose) or surplus (to gain), combined with regular physical activity and adequate protein. Crash diets are counterproductive and hard to sustain. Use a calorie calculator to set realistic daily targets and consult a doctor or dietitian for personalised advice.