145.7
lb
144
lb
145.7
lb
147.5
lb
145.7
lb
66.1
kg
67
in
145.7
lb
144
lb
145.7
lb
147.5
lb
145.7
lb
66.1
kg
67
in
The concept of ideal body weight (IBW) has long been used in medicine and nutrition to estimate the weight at which an individual of a given height is expected to have the lowest health risk and highest overall wellbeing. Unlike BMI, which classifies individuals into broad categories, IBW formulas produce a specific target weight based on height and sex, making them useful for clinical drug dosing calculations, nutritional assessments, and fitness goal setting.
This calculator provides results from four different evidence-based IBW formulas: the Devine formula (1974, widely used in pharmacology), the Robinson formula (1983, considered more accurate for shorter individuals), the Miller formula (1983, tends to produce higher estimates), and the Hamwi formula (1964, originally developed for patients with diabetes). Each formula was derived from different datasets and methods, which is why their results can vary by 10–20 lbs for the same height.
It is important to understand that ideal weight is a statistical concept, not an absolute health target. Body frame size, muscle mass, bone density, age, and individual health history all affect what weight is truly ideal for a specific person. Use the range across formulas as a guide and consult with a healthcare provider to determine a realistic and healthy weight goal for your unique circumstances.
All four formulas start from a base weight at 5 feet and add a fixed amount per additional inch. The formulas in metric units (kg) are:
Devine: Males: $$IBW = 50 + 2.3 \times i$$ | Females: $$IBW = 45.5 + 2.3 \times i$$
Robinson: Males: $$IBW = 52 + 1.9 \times i$$ | Females: $$IBW = 49 + 1.7 \times i$$
Miller: Males: $$IBW = 56.2 + 1.41 \times i$$ | Females: $$IBW = 53.1 + 1.36 \times i$$
Hamwi: Males: $$IBW = 48 + 2.7 \times i$$ | Females: $$IBW = 45.5 + 2.2 \times i$$
Where $$i$$ is the number of inches above 5 feet. Results in kg are multiplied by 2.20462 to convert to pounds. For individuals under 5 feet, the formulas may produce negative adjustments; alternative methods such as BMI-based ideal weight may be more appropriate in those cases.
The four formulas typically span a range of about 5–15 lbs for most heights. The midpoint of the range provides a reasonable consensus target. The Devine formula is most commonly used in clinical settings (particularly for drug dosing), while Robinson is often cited in nutrition contexts. If you are significantly above the range across all four formulas, you may benefit from gradual weight loss; if you are well within the range, focus on body composition (muscle vs. fat) rather than the scale number.
Inputs
Results
Ideal weight range of 162–172 lbs for a 5'9" male. The consensus midpoint is approximately 167 lbs.
Inputs
Results
Ideal weight range of 128–135 lbs for a 5'5" female, with a consensus midpoint of about 131 lbs.
No single formula is universally most accurate — each was derived from a different population sample. The Devine formula is most widely used in pharmacokinetics and clinical drug dosing. The Robinson formula is considered slightly more refined for the general population. For practical fitness purposes, treating the range across all four formulas as a healthy weight zone is more useful than fixating on a single value.
No. All four IBW formulas are based solely on height and sex. They do not account for muscle mass, bone density, or body composition. A muscular athlete may weigh significantly more than these formulas suggest while having an excellent body composition. In such cases, body fat percentage is a more meaningful metric than IBW.
IBW formulas were derived from insurance industry data and population averages from the mid-20th century. They may not reflect modern body composition standards, especially for people who exercise regularly. If your BMI is in the normal range, your body fat percentage is healthy, and your blood markers are normal, you may well be at a healthy weight despite being above historical IBW estimates.
No. These formulas are designed for adults (typically 18+). For children and adolescents, growth charts with age- and sex-specific BMI percentiles are the appropriate tool for assessing healthy weight ranges.
IBW is a guideline, not a mandate. More important health targets include achieving a BMI in the normal range (18.5–24.9), a healthy body fat percentage, normal blood pressure, cholesterol, and blood sugar levels. Small losses of even 5–10% of body weight in overweight individuals have been shown to significantly reduce chronic disease risk — you don't need to reach "ideal" weight to gain major health benefits.
In clinical medicine, IBW (typically the Devine formula) is used to calculate medication doses — particularly for drugs like antibiotics, chemotherapy agents, and anesthetics — where dosing by total body weight could lead to toxicity in overweight patients. Adjusted body weight formulas that blend IBW and actual weight are also used for obese patients.
Roboculator Team
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