Ideal Body Weight Calculator

An Ideal Body Weight (IBW) calculator estimates a reference healthy weight using only your height and gender, based on formulas originally developed for clinical use — most commonly the Devine formula. Rather than giving you a single number to chase, a good IBW calculator should show a healthy weight range, since formula-based estimates don't account for muscle mass, bone density, or body frame. It's a useful starting point for fitness and nutrition planning, not a diagnosis of what you 'should' weigh.

The most common method is the Devine formula: for men, start at 50 kg and add 2.3 kg for every inch of height over 5 feet; for women, start at 45.5 kg and add the same 2.3 kg per inch. For example, a man who is 5 ft 10 in tall would have an estimated IBW of 50 + (10 × 2.3) = 73 kg. Other formulas — Hamwi, Robinson, and Miller — use slightly different baseline weights and per-inch adjustments, which is why you may see different ideal weight figures depending on the source. None of these formulas use age, body fat percentage, or activity level as inputs.

No, and the two measure different things. BMI (Body Mass Index) is calculated from your current height and current weight to classify you into categories like underweight, normal, overweight, or obese. Ideal body weight, by contrast, is calculated only from your height and gender to estimate a target weight you could aim for. You can have a 'normal' BMI while being well outside your IBW range, or vice versa — they're complementary tools, not interchangeable ones. Many people check both: BMI to see where they currently stand, and IBW to set a goal.

IBW gives you a concrete, evidence-based reference point instead of guessing at a weight loss or weight gain goal. It's also used clinically — doctors and pharmacists use ideal body weight (or a related figure called adjusted body weight) to calculate accurate dosages for certain medications, especially in patients who are significantly overweight or underweight, because dosing by total body weight alone can be unsafe in those cases. For everyday use, it helps frame realistic fitness and nutrition targets rather than chasing an arbitrary number.

Athletes and anyone with above-average muscle mass should treat IBW results as a loose reference rather than a target. Because the underlying formulas were built from general population data, they assume an average ratio of muscle to fat. A muscular athlete will often weigh more than their 'ideal' weight while still being lean and healthy, since muscle is denser than fat. In these cases, body composition metrics (body fat percentage, waist-to-hip ratio) are more meaningful than IBW or BMI alone.

Height and gender are the only two inputs the standard formulas use, but several other factors influence what's actually healthy for a given individual: body frame size (small, medium, or large), muscle mass, age, bone density, and overall health history. Two people of the same height and gender can have very different healthy weights depending on these factors. This is why doctors generally use IBW as one data point alongside BMI, waist circumference, and a physical assessment — not as a standalone verdict.

Yes — IBW is a reasonable starting point for setting a realistic weight loss or weight gain target, especially when you use the full healthy range rather than the single midpoint number. A practical approach is to aim for the upper end of your healthy range if you carry more muscle mass, or the middle of the range for a general fitness goal. For a personalized plan, it's worth combining this with a calorie or BMI calculator and, ideally, input from a healthcare provider or registered dietitian, particularly if you have an existing medical condition.

Standard IBW equations do not directly measure frame size, muscle mass, bone density, or fat distribution. A person with a larger frame or more muscle may be healthy above the estimate, while a smaller-framed person may fall below it. Avoid applying a fixed frame-size adjustment as a medical rule.

Do not select or change a medicine dose from this page. Clinical dosing may use actual, ideal, lean, or adjusted body weight depending on the medicine, kidney function, age, and clinical protocol. A qualified prescriber or pharmacist should choose the appropriate weight and dose.