"Ideal weight" is a useful fiction
There is no single weight that is medically correct for a given height. What exists is a range — a window of body weights where all-cause mortality, cardiometabolic risk, and mobility all sit near their statistical minimum. This calculator shows you four different estimates of the middle of that window, plus the BMI-based healthy range (18.5–24.9), because different formulas capture different aspects of what "ideal" means.
The four formulas
Devine (1974)
Originally built to standardize medication dosing in hospitals, not to describe healthy body weight. It caught on anyway because the numbers were close enough and the math was trivial. For men: 50 kg + 2.3 kg per inch over 5 feet. For women: 45.5 kg + 2.3 kg per inch over 5 feet. Slightly lean by modern standards.
Robinson (1983)
A refinement of Devine using more recent population data. Tends to sit closest to what most sports medicine physicians would call a healthy fit weight.
Hamwi (1964)
A dietitian's shortcut designed to be computed at the bedside. Runs slightly higher than Devine or Robinson — a little more forgiving, a little closer to how real bodies at healthy weight tend to cluster.
BMI-based range
The width of BMI 18.5–24.9 translated back into pounds. This is the most honest answer to "how much should I weigh" — it acknowledges a range rather than a single number. The BMI calculator tells you where you fall within it.
The frame-size adjustment
Body frame refers to bone structure — wrist and elbow width, not body fat. Someone with a small frame at 5'10" will carry their healthy weight 5–10% lower than someone with a large frame at the same height, because their skeleton weighs less and supports less muscle mass. We apply a ±10% adjustment to the three classic formulas based on the frame size you select. The BMI-based range is not frame-adjusted because BMI by design doesn't differentiate.
Crude test for frame size: circle your dominant wrist with your opposite thumb and middle finger. If they overlap, you have a small frame. If they just touch, medium. If there's a gap, large.
Why height alone underdetermines weight
Two people at 5'10" can both be at perfectly healthy weights while varying by 40 pounds. One might be a 150-pound distance runner; the other might be a 190-pound rugby player. Neither is wrong. Height-based formulas can't distinguish between them because they don't know about body composition. This is why the body fat percentage calculator is the more useful companion tool for anyone who lifts weights or plays sports.
How to use an ideal-weight estimate
As a starting range, not a finish line. If your weight sits 5–10 pounds above the upper end of the range and you feel fine, your clothes fit, and your labs are clean, the number is cosmetic, not medical. If you're 20+ pounds above and carrying it as visceral fat around the midsection, it's worth addressing — see the waist-to-hip ratio tool for a better risk signal than weight alone.
To move weight toward a target, the sustainable path goes through the TDEE calculator (to set calories) and the macro calculator (to split them with enough protein to protect muscle).
Weight ranges by context
Endurance athletes
Tend to sit at the lean end of the ideal range, often 5–10 lb below the formula midpoint. Low body fat (8–15% for men, 14–21% for women) and relatively low muscle mass.
Strength athletes and lifters
Often sit at or above the upper end of the ideal range because of carried muscle mass. BMI may flag them as overweight; body fat percentage usually shows low single-digit or low-teens values.
General population adults
Most sit somewhere between the Devine and Hamwi estimates with average muscle mass.
Older adults (65+)
Research suggests a slight upward shift — being a bit heavier than the strict ideal-weight formulas suggest may be protective against sarcopenia and illness-related weight loss. A BMI of 23–27 is often considered optimal in this age group.
FAQ
Why do the formulas disagree?
They were developed in different decades, using different populations, for different purposes. Averaging them is a reasonable way to sand off those edges.
What if I'm much shorter than 5 feet?
The Devine and Hamwi formulas weren't designed for short stature and can produce low or nonsensical numbers. For children, teens, and adults under 5'0", defer to your doctor's growth charts or population-specific references.
Are these formulas different for Asian populations?
Yes — the WHO recommends lower BMI cutoffs for East and South Asian populations (23 overweight, 27.5 obese). A version of the ideal-weight range tuned to that would sit roughly 5–8% lower than the standard output. Discuss with your physician if relevant.
Should I lose weight to hit the number?
Only if you're meaningfully above the range and that weight is carried as fat, not muscle. Chasing the exact number at the cost of dropping muscle almost always worsens health. The scale is downstream of body composition, not the other way around.