An ideal weight calculator estimates a person's "ideal body weight" (IBW) based on height and sex using the Devine formula, the most widely-used clinical estimation method since the 1970s. The number is a rough reference point used in medical settings for dosing weight-based medications, not a personal weight-loss target.
Enter your height and sex; the calculator returns the Devine IBW plus a ±10% range, which most clinicians treat as the "healthy weight" band for that height. Real healthy weight depends on body composition (muscle vs. fat), age, fitness level, and ethnicity, none of which these formulas capture.
Key takeaway
The phrase "ideal weight" oversells what these formulas actually measure. They were developed in the 1970s to help clinicians estimate medication dosages for hospitalized patients, not to define what individuals should weigh. Healthy bodies span a wide range of weights at any given height; treat the calculator's number as one reference point, not a target.
How it's calculated
The Devine formula (1974), still the clinical standard:
- Men:
IBW(kg) = 50 + 2.3 × (height in inches − 60) - Women:
IBW(kg) = 45.5 + 2.3 × (height in inches − 60)
This calculator converts the result to pounds (multiply by 2.205) and shows a ±10% healthy range, the rough band most clinical guidelines consider acceptable for an adult of that height.
Other common formulas (Robinson, Miller, Hamwi) produce slightly different numbers but agree within a few pounds for most heights. They were all derived from population averages, primarily based on 20th-century North American adults, so they don't generalize cleanly across all ethnic groups or modern body compositions.
Source: Devine formula (1974), still standard for clinical IBW estimation
Examples
5'10" (70 in) man
- Height 70 in
- Sex Male
Devine IBW for a 5'10" man is 73 kg (~161 lb), with a healthy range of roughly 65.7–80.3 kg (145–177 lb). Note: the calculator outputs in kg here despite the imperial height input, Devine is natively a metric formula. Multiply kg by 2.205 to get pounds if you prefer.
5'5" (65 in) woman
- Height 65 in
- Sex Female
Devine IBW for a 5'5" woman is 57 kg (~126 lb), with a healthy range of 51.3–62.7 kg (113–138 lb). This range overlaps closely with the BMI-based "normal weight" band of about 111–149 lb at this height, they're separate formulas pointing at the same general territory.
Frequently asked questions
Are ideal weight formulas accurate for everyone?
No. The Devine formula was derived from a 1970s North American population and doesn't generalize cleanly to muscular individuals (it underestimates healthy weight), the elderly (loses relevance with age-related body composition changes), or non-European ethnic backgrounds (where average healthy body sizes can differ). Clinical practice has been moving toward body-composition-based assessment (DEXA, BodPod) for individual decisions while keeping IBW as a quick population-level reference.
Should I try to match my "ideal" weight?
Probably not directly. IBW is not a personal goal, it's a statistical midpoint of population averages, used in medicine for dosing math. For most adults, a far better target is "weight at which I have good cardiovascular health, normal blood markers, adequate fitness, and feel good." That's often within ±15 lb of the IBW number for tall/normal builds, but can deviate significantly for muscular or athletic individuals.
What's the difference between Devine, Robinson, Miller, and Hamwi?
All four are linear formulas derived from population data, they agree within ~5-10 lb for most heights. Devine is the most widely-used clinical version. Robinson (1983) updated it slightly with smaller per-inch increments. Miller (1983) is gentler at extremes. Hamwi (1964) is the oldest and uses slightly larger steps. None is meaningfully more accurate than the others for general use; pick one and stick with it for comparisons.
Does this work for kids or teens?
No. IBW formulas are for adults only. Pediatric weight assessment uses growth charts (CDC and WHO) that account for age, sex, and percentile rather than a single ideal number. For anyone under 18, refer to a pediatrician's growth-chart assessment instead.