⚡ FREE IDEAL WEIGHT CALCULATOR: TARGET BODY WEIGHT (LBS & INCHES) ⚡

An ideal weight calculator is a tool that estimates the healthiest body weight for a person based on their height and biological sex. It uses one or more scientifically published formulas — such as Robinson (1983), Devine (1974), Miller (1983), or Hamwi (1964) — to generate a target weight range. The calculator does not measure your body fat, muscle mass, or actual health status; it simply provides a height-based benchmark used in fitness and clinical settings to set weight management goals.

This calculator only requires two inputs:

• Height — in feet and inches (Imperial) or centimeters (Metric)
• Biological sex — Male or Female

Your current weight, age, and activity level are not required because the four formulas used are height-and-sex-based only. If you want a more complete picture factoring in age and activity, use the BMI Calculator or TDEE Calculator alongside these results.

Ideal body weight (IBW) is a single estimated target based on height-based formulas. It represents what researchers calculated as optimal for a general population. Healthy weight is a broader range defined by BMI values between 18.5 and 24.9 — meaning there is a span of healthy weights, not just one number. Your ideal weight from this calculator will typically fall somewhere within the healthy BMI range, but the two are different concepts. IBW is more specific; healthy weight is a wider, more inclusive range. Both are tools — neither is a definitive verdict on your health.

Both tools serve different purposes and are best used together. BMI gives you a range of healthy weights (the 18.5–24.9 range), while IBW gives you a specific point target within or near that range. IBW is more precise but more rigid. BMI is broader but more flexible. For most people:

• Use IBW as your specific goal weight target
• Use BMI to confirm you’re within the healthy range broadly
• Use body fat % as the most accurate indicator of actual health

Check your BMI using our BMI Calculator alongside this result.

No single formula is universally the most accurate — each was built for a different population and purpose. That said, among the four:

• Devine (1974) is the most medically validated and widely used in clinical and pharmaceutical dosing settings
• Robinson (1983) is the most commonly referenced in modern fitness contexts
• Miller (1983) tends to give slightly higher estimates and may suit larger-framed individuals better
• Hamwi (1964) is the oldest and simplest, still used as a fast clinical reference

The averaged result across all four formulas is the most practical and balanced target for the general population, which is why this calculator displays it prominently.

The calculator is reasonably accurate for average-build, non-athletic adults. All four formulas were developed using general population data and are most reliable for people who are sedentary to moderately active. However, accuracy decreases for:

• Competitive athletes and bodybuilders with high lean muscle mass
• People with very small or very large bone frames
• Individuals under 18 or over 65 years old
• People with medical conditions affecting body composition

Using all four formulas together and averaging them — as this calculator does — improves reliability compared to using any single formula in isolation.

Each formula was developed independently by different researchers across different decades (1964, 1974, and 1983), using different population samples and methodologies. They each start from a different base weight and add a different per-inch increment. The result is that at average heights (5’4″–5’9″), the four formulas typically cluster within 7–10 lbs of each other. At taller heights (6’2″+), the spread can widen to 20+ lbs because small per-inch differences compound over many inches above 5 feet. This spread is not a flaw — it reflects genuine scientific uncertainty about what constitutes “ideal” weight for any individual.

Each formula uses a different base weight at 5 feet and a different per-inch multiplier. Robinson uses a base of 52 kg for males with 1.9 kg per extra inch, while Devine uses 50 kg base with 2.3 kg per inch. This means at shorter heights, Robinson gives a slightly higher estimate, but as height increases, Devine’s higher per-inch rate catches up and surpasses Robinson. The formulas were developed by different researchers using different population samples in different decades, which explains the variation. This is exactly why averaging all four gives the most reliable result.

The Devine formula was created by Dr. B.J. Devine in 1974 originally to calculate appropriate drug dosages — particularly for medications where dosing is tied to body weight. Doctors needed a quick, consistent way to estimate a patient’s “lean weight” without access to body fat measurement equipment. The formula (50 kg + 2.3 kg per inch over 5 feet for males; 45.5 kg for females) became so widely adopted in hospitals and pharmacies that it crossed over into general fitness and health contexts. Today it remains the most medically cited of all the IBW formulas.

All four formulas calculate results natively in kilograms (kg) — that is the unit used in the original published research. When you select Imperial mode, the calculator multiplies every kg result by the conversion factor 2.20462 to convert to pounds before displaying anything. For example, a result of 70 kg becomes 70 × 2.20462 = 154.3 lbs. The reverse conversion (lbs to kg) uses division by the same factor. Height input in centimeters is converted to inches by dividing by 2.54 before being fed into the formulas.

The four formulas used in this calculator (Robinson, Miller, Devine, Hamwi) are age-independent — they only use height and sex to calculate IBW. However, in reality, body composition changes significantly with age. Adults over 50 naturally lose lean muscle mass (sarcopenia) and may carry more fat at the same scale weight compared to younger adults. For older adults, body fat percentage and functional strength are more meaningful targets than IBW alone. Pair this calculator with a Body Fat Calculator for age-relevant context.

Males and females have fundamentally different body compositions even at identical heights. Men naturally carry more lean muscle mass and denser bone structure than women at the same height. Women naturally carry a higher essential fat percentage (roughly 10–13% vs. 2–5% for men) which is necessary for hormonal and reproductive health. The formulas account for these structural differences by using separate base weights and per-inch multipliers for each sex. A 5’6″ male has a higher IBW than a 5’6″ female because his body is physiologically expected to carry more lean mass at that height.

The four formulas in this calculator do not directly account for frame size. However, frame size is a real physiological variable — people with larger bone structures naturally weigh more at the same height. A general rule used by many dietitians: adjust the IBW result by ±10% based on frame size:

• Small frame: subtract up to 10% from your average IBW
• Medium frame: use the average IBW as-is
• Large frame: add up to 10% to your average IBW

You can estimate your frame size by measuring wrist circumference relative to height — a commonly used clinical method endorsed by many dietitians and fitness coaches.

No — IBW formulas were not designed for strength athletes. Bodybuilders and powerlifters carry significantly more lean muscle mass than the general population used to develop these formulas. A competitive male powerlifter standing 5’10” might weigh 220 lbs at 10% body fat — completely healthy and optimally performing — while every IBW formula puts his “ideal” at 155–165 lbs. For strength athletes, body fat percentage (target: 8–15% for males, 15–22% for females in performance contexts) and lean body mass are far more relevant metrics. Use our Lean Body Mass Calculator instead.

Not necessarily. IBW formulas have no knowledge of what your extra weight is made of. If you weight-train regularly, your additional weight above the IBW result may be lean muscle mass — which is healthy and desirable. A 6-foot male who lifts 5 days a week at 195 lbs may have 12% body fat and be in peak health, even though every IBW formula puts his “ideal” at approximately 168–177 lbs. Always check your body fat percentage before drawing conclusions from your IBW result alone. Scale weight without body composition context is almost meaningless.

Being below your IBW range is worth taking seriously. Underweight status can indicate inadequate muscle mass, low bone density, nutritional deficiency, or underlying health conditions. According to the CDC, underweight adults face elevated risks of immune dysfunction, fatigue, and osteoporosis. If you’re below your IBW range and not a competitive endurance athlete (where lighter frames can be intentional), consult a registered dietitian or physician. If you’re underweight due to low muscle mass, a structured progressive overload program with adequate protein intake (0.7–1g per lb of bodyweight) is the most effective solution.

Being significantly above your ideal weight — particularly due to excess body fat rather than muscle — is associated with elevated risk for several serious conditions according to the CDC:

• Type 2 diabetes — excess visceral fat impairs insulin sensitivity
• Cardiovascular disease — elevated cholesterol, blood pressure, and arterial stress
• Sleep apnea — excess neck and abdominal fat obstructs the airway
• Joint degeneration — excess weight accelerates knee and hip cartilage breakdown
• Certain cancers — obesity is linked to 13 types including colorectal and breast cancer

Even a 5–10% reduction in body weight has been shown to meaningfully reduce risk across all of these categories.

Being significantly underweight (below the lower end of your IBW formula range) carries its own serious health risks that are often overlooked:

• Malnutrition — insufficient intake of macro and micronutrients
• Osteoporosis — low body weight is associated with reduced bone mineral density
• Immune suppression — inadequate fat stores compromise immune function
• Hormonal disruption — women may experience loss of menstrual cycle (amenorrhea); men may see testosterone decline
• Muscle atrophy — the body breaks down muscle tissue for energy when underfed

If you are consistently underweight, consult a registered dietitian and physician before starting any aggressive training program.

The four formulas used in this calculator were developed for adults aged 18 and over and are not validated for children or teenagers whose bodies are still developing. For individuals under 18, pediatric growth charts from the CDC or BMI-for-age percentile tools are the appropriate reference. Applying adult IBW formulas to teenagers can produce misleading results because adolescent body composition changes rapidly during puberty and does not match the adult population baselines these formulas were calibrated against.

You can use it as a rough reference, but with important caveats. Adults over 65 naturally experience age-related muscle loss (sarcopenia) and bone density reduction, meaning their body composition differs significantly from younger adults on whom these formulas were calibrated. Some geriatric health guidelines actually suggest that a slightly higher body weight in older adults provides protective benefits — including a cushioning effect during falls and reserves during illness. For seniors, functional strength, mobility, and cardiovascular health metrics are far more meaningful than hitting an IBW number derived from general adult population data.

IBW calculators are not applicable during pregnancy. Pregnancy naturally and necessarily increases body weight through fetal growth, amniotic fluid, placenta, increased blood volume, and fat stores needed for breastfeeding. The National Institute of Diabetes provides separate gestational weight gain guidelines based on pre-pregnancy BMI. Use our Pregnancy Weight Gain Calculator for appropriate targets during pregnancy. Return to IBW tracking postpartum once cleared by your OB-GYN — typically 6–12 weeks after delivery.

No. Weight loss surgery (bariatric surgery) targets are calculated differently and are set by bariatric surgeons based on factors including initial BMI, comorbidities, age, and the specific procedure performed. The Devine IBW formula is sometimes referenced in bariatric contexts for adjusted body weight calculations in severely obese patients, but the actual post-surgery target weight is individualized in a clinical setting. If you are exploring bariatric surgery options, your surgical team will provide specific weight targets that will differ from what a general IBW calculator produces.

For healthy adults with no underlying conditions, the calculator can be used freely as an informational tool without requiring a medical consultation. However, you should speak to a physician or registered dietitian before starting a structured weight loss program if you:

• Have been diagnosed with diabetes, heart disease, thyroid disorders, or kidney disease
• Are taking prescription medications that affect metabolism or weight
• Have a history of eating disorders
• Are significantly obese (BMI 35+) and considering aggressive caloric restriction
• Are pregnant, postpartum, or breastfeeding

This calculator is an educational tool — it does not constitute medical advice.