Calculate your ideal body weight using four clinical formulas (Devine, Robinson, Miller, Hamwi) — see the multi-formula range and understand how IBW is used in medicine and pharmacy.
This ideal weight calculator is designed for adults who want to understand their height-based weight reference point using the same clinical formulas used in medicine and pharmacy. Enter your height (in feet/inches or centimeters) and sex, and the calculator returns IBW estimates from the Devine, Robinson, Miller, and Hamwi formulas — both in pounds and kilograms — plus a brief comparison showing the range across all four. The tool is particularly useful for healthcare students, patients who have had IBW referenced in a clinical conversation, people working with pharmacists on weight-based dosing, and individuals setting a long-range weight goal with clinical grounding. Unlike a BMI-based healthy weight range (which this calculator is not — see the Healthy Weight Calculator for that), IBW formulas produce a single target weight, not a range. That's both their precision and their limitation, covered in depth below.
Most everyone has at some point tried to lose weight, or at least known somebody who has. This is largely due to the perception of an "ideal" body weight, which is often based on what we see promoted through various media such as social media, TV, movies, and magazines. Although ideal body weight (IBW) today is sometimes based on perceived visual appeal, IBW was actually introduced to estimate dosages for medical use, and the formulas that calculate it are not at all related to how a person looks at a given weight.
It has since been determined that the metabolism of certain drugs is more based on IBW than it is total body weight. Today, IBW is also used widely throughout sports, since many sports classify people based on their body weight.
Note that IBW is not a perfect measurement. It does not consider the percentages of body fat and muscle in a person's body. This means that it is possible for highly fit, healthy athletes to be considered overweight based on their IBW. This is why IBW should be considered as an imperfect measure and not necessarily indicative of health.
Enter your height and sex, select your unit preference, and calculate. The result shows IBW estimates from each of the four clinical formulas, typically expressed to the nearest 0.5 kg or pound. You'll see a range — for example, a 5'6" woman might get results from 130 lb (Hamwi) to 139 lb (Devine). The average of these estimates gives a reasonable central target, but none of the four should be treated as a precise personal goal without considering muscle mass, bone density, age, and body composition. If your current weight falls within or close to the multi-formula range, you're in the clinical reference zone for your height and sex. A provider conversation makes the most sense if you're planning to pursue IBW as a specific weight-loss target.
The four clinical IBW formulas for adults (height in inches, result in kilograms):
Example: For a 5'8" (68 inches) man: Devine gives 50 + 2.3×8 = 68.4 kg; Robinson gives 52 + 1.9×8 = 67.2 kg; Miller gives 56.2 + 1.41×8 = 67.5 kg; Hamwi gives 48 + 2.7×8 = 69.6 kg.
This is one of the most commonly confused distinctions in weight management. Ideal body weight (from the Devine/Robinson/Miller/Hamwi formulas) produces a single target weight based on height and sex — a clinical shorthand developed primarily for pharmacokinetic calculations. Healthy weight (from BMI) produces a range: the weight range corresponding to a BMI of 18.5–24.9 for your height. For a 5'8" man, the IBW formulas converge around 68 kg (150 lb), while the healthy BMI range spans 60–81 kg (132–179 lb) — a much wider window. Neither is wrong; they answer different questions. IBW is a clinical reference point; healthy weight is a population-level epidemiological range. For personal weight goals, the healthy weight range is more inclusive and may be more realistic; for clinical applications like medication dosing, IBW formulas are standard.
The World Health Organization's (WHO) recommended healthy BMI range is 18.5 - 25 for both males and females. Based on the BMI range, it is possible to find out a healthy weight for any given height.
BMI is a commonly used metric for determining IBW. It is widely used in the medical field as a quick indicator of possible health complications. Generally, the higher the BMI, the higher the chance a person will suffer from health problems such as obesity, diabetes, heart disease, and many more.
All the formulas above are for adults age 18 or older. For children and teens, please refer to BMI charts published by the Centers for Disease Control and Prevention (CDC). The CDC recommends that children maintain a BMI between the 5th and 85th percentile based on their age.
The primary modern use of IBW calculations isn't personal weight management — it's pharmaceutical and clinical dosing. Renal clearance-based drug dosing (including aminoglycosides, certain chemotherapy agents, and heparin), mechanical ventilator tidal volume settings, and anesthesia calculations all use IBW or adjusted body weight (ABW) as reference inputs because pharmacokinetics generally track lean mass, not total body weight. A 300 lb patient doesn't receive 300% of the dose intended for a 100 lb patient; IBW anchors the calculation closer to lean tissue volume. For patients, understanding this context clarifies why a hospitalist might mention IBW during a clinical encounter — it's not a cosmetic target but a dosing reference. If you've had IBW referenced in a medical conversation, this calculator gives you the same number using the same formulas.
The female IBW formulas yield lower reference weights than male formulas for the same height because they account for the average difference in lean mass between sexes. For a 5'4" (64 inches) woman, the four formulas typically cluster between 112–124 lb (51–56 kg); for a 5'7" woman, between 126–138 lb (57–63 kg); for a 5'10" woman, between 143–153 lb (65–69 kg). These targets reflect clinical history based on average frame size. Women with larger frames, more muscle mass, or different bone density than the "average" female assumed in 1960s–1980s formula derivation may fall outside these estimates while being perfectly healthy. The formulas don't account for ethnic variation in body composition or the fact that average American body weights today sit substantially higher than when these formulas were derived.
In theory, age shouldn't be a large determinant of IBW past ages 14-15 for girls and 16-17 for boys, after which most people stop growing. It is expected that human males and females lose 1.5 and 2 inches in height respectively by age 70. As people age, lean muscle mass decreases and it's easier to accumulate excess body fat.
Generally, females weigh less than males even though they naturally have a higher percentage of body fat. This is because the male body generally has higher muscle mass, and muscle is heavier than fat. Women generally have lower bone density, and males tend to be taller than females.
The taller the person, the more muscle mass and body fat they have, which results in more weight. A male at a similar height to a female should weigh about 10-20% heavier.
Body frame size is another factor that can have a significant impact on the measurement of ideal weight. Body frame size is typically categorized as small, medium, or large boned. It is measured based on the circumference of a person's wrist in relation to their height.
| Height | Small Boned | Medium Boned | Large Boned |
|---|---|---|---|
| Under 5'2" | < 5.5" | 5.5" – 5.75" | > 5.75" |
| 5'2" – 5'5" | < 6.0" | 6.0" – 6.25" | > 6.25" |
| 5'5" – 5'8" | < 6.25" | 6.25" – 6.5" | > 6.5" |
| Over 5'8" | < 6.5" | 6.5" – 6.75" | > 6.75" |
| Height | Small Boned | Medium Boned | Large Boned |
|---|---|---|---|
| Over 5'5" | 5.5" – 6.5" | 6.5" – 7.5" | > 7.5" |
A person who is large boned will naturally weigh more than someone who is small boned, even at the same height, making body frame size a factor that can affect measurements such as IBW and BMI.
IBW formulas have three structural limitations that matter for personal use. First, they ignore muscle mass: a female athlete at 5'5" carrying 140 lb with 20% body fat will score "overweight" against Devine's 125 lb IBW, despite excellent body composition. Second, they don't adjust for age: an IBW of 68 kg for a 5'8" man applies regardless of whether he's 25 or 75, ignoring the documented protective effect of slightly higher weight in older adults. Third, frame size variation — the range between small-framed and large-framed individuals at the same height — can legitimately shift a realistic weight target by 10–15% in either direction. Some calculators offer a simple frame size adjustment based on wrist circumference; use those corrections if your frame clearly falls outside average. For athletes in particular, body composition measurement (DEXA scan, skinfold, or bioelectrical impedance) provides far more meaningful guidance than IBW.
Height is the only variable in IBW formulas, which means your entire result pivots on accurate height measurement — a half-inch error shifts the target by roughly 1.2–1.5 kg depending on the formula. Sex determines which base constant is applied at each formula and produces consistently lower targets for women. The choice of formula matters: the spread between Hamwi's estimate (often the highest) and Robinson's (often the lowest) can be 5–10 lb for tall individuals. Frame size, muscle mass, and bone density are the factors that IBW formulas cannot see — they're the reason an IBW result for a person who deviates significantly from "average frame" may not be a meaningful personal target. Age is the other invisible factor: clinical IBW formulas were not derived from geriatric populations.
Amara is a 30-year-old in Houston, 5'5" (65 inches), 158 lb. She's curious about her clinical IBW after her physician mentioned it at a checkup. Devine: 45.5 + 2.3×5 = 57 kg (126 lb); Robinson: 49 + 1.7×5 = 57.5 kg (127 lb); Miller: 53.1 + 1.36×5 = 60 kg (132 lb); Hamwi: 45.4 + 2.3×5 = 57 kg (126 lb). The four formulas cluster at 126–132 lb. Her current 158 lb is 26–32 lb above the multi-formula range, a useful starting point for her weight-loss conversation with her provider.
Darnell is a 26-year-old strength coach in Minneapolis, 6'2" (74 inches), 215 lb, with an estimated body fat of 12%. Devine IBW: 50 + 2.3×14 = 82.2 kg (181 lb); Robinson: 52 + 1.9×14 = 78.6 kg (173 lb); Miller: 56.2 + 1.41×14 = 75.9 kg (167 lb); Hamwi: 48 + 2.7×14 = 85.8 kg (189 lb). Formula range: 167–189 lb. Darnell sits 26–48 lb above the IBW range — but 88% of his 215 lb is lean mass. This is exactly where IBW formulas fail muscular individuals; his clinician would use adjusted body weight, not plain IBW, for any medication calculation.
Use the multi-formula average as your reference point rather than anchoring on any single formula; the range between them is more informative than any single number.
If your current weight is significantly above the IBW range, use it as a directional benchmark, not a mandate — a realistic weight loss goal might land you in the healthy BMI range rather than at the IBW formula target.
Check your actual body composition if you're muscular or athletic before treating an IBW number as meaningful; DEXA or caliper testing gives far more actionable data.
For medication dosing questions, always defer to your pharmacist or physician — they'll apply any necessary adjustments (like adjusted body weight for obese patients) that this calculator doesn't factor in.
Remember that the formulas were developed primarily on white male clinical populations in the mid-20th century; users from different backgrounds should treat results as approximate references.
Pair this result with the Healthy Weight Calculator for a range-based perspective that may be more practical as a personal goal.
There are limitations to all the formulas and methods. Because the formulas are designed to be as applicable to as wide a range of people as possible, they cannot be highly accurate for every single individual. The formulas factor only height and gender, and there are no considerations for physical handicaps, people on the extreme ends of the spectrum, activity levels, or muscle mass to body fat ratios. Our Ideal Weight Calculator is meant to be used as a general guideline based on popular formulas, and its results are not intended as strict values that a person must achieve to be considered an "ideal weight."
It depends on your sex and which formula you use. For a 5'8" man, the four clinical formulas (Devine, Robinson, Miller, Hamwi) estimate ideal weight between 67–70 kg (147–154 lb). For a 5'8" woman, the range is 60–64 kg (132–141 lb). Use the calculator above for your specific height.
Running the four clinical formulas for a 5'6" (66 inches) woman produces estimates between approximately 121–130 lb (55–59 kg). The Hamwi and Devine formulas tend to land at the lower end; Miller produces the highest estimate for women.
The Devine formula (1974) estimates: Men: IBW (kg) = 50 + 2.3 × (height in inches − 60); Women: IBW (kg) = 45.5 + 2.3 × (height in inches − 60). It was originally developed for pharmaceutical dosing calculations, not personal weight goals.
No. Ideal body weight (IBW) formulas produce a single point estimate based on height and sex. Healthy weight refers to the BMI range of 18.5–24.9 translated to a pound range for your height — a wider band. For a 5'8" man, IBW is about 150 lb; the healthy weight range is 132–179 lb.
They're accurate clinical shorthand, not precise personal targets. All four formulas ignore muscle mass, bone density, age, and frame size. For heavily muscular individuals or those outside the average frame the formulas were derived from, the targets may under- or overestimate a realistic personal goal by 10–20 lb.
The clinical formulas don't adjust for age, but the body does change: muscle mass declines with age (sarcopenia) and a slightly higher weight may actually be protective for adults over 65. Some geriatric guidelines suggest a BMI of 23–27 rather than the standard 18.5–24.9 healthy range for older adults.
Physicians and pharmacists use IBW for weight-based drug dosing, particularly for medications where lean mass drives pharmacokinetics. Ventilator tidal volume settings and chemotherapy doses are common examples. It's a clinical anchor, not a lifestyle goal.
A safe, sustainable rate of weight loss is 1–2 lb per week, achieved through a 500–1,000 calorie daily deficit. Starting with an accurate TDEE estimate and using the Macro Calculator to structure intake is more effective than simply knowing an IBW target.
Brief disclaimer: This calculator provides educational IBW estimates using four clinical formulas (Devine, Robinson, Miller, Hamwi). These formulas were developed primarily for pharmaceutical dosing on mid-20th century clinical populations and do not account for muscle mass, bone density, frame size, age, or ethnicity. Results are clinical reference points, not personal weight mandates. Consult a healthcare provider or registered dietitian for personalized weight guidance.