Ideal Weight Calculator
Three standard answers — Devine, Robinson, and the healthy-BMI band — because one number was never the truth.
Find your healthy weight range
Where "ideal weight" formulas come from
The famous formulas weren't invented for dieting. The Devine formula (1974) — 50 kg + 2.3 kg per inch over five feet for men, 45.5 kg base for women — was created to dose medications, and hospitals still use it for exactly that. Robinson (1983) refined it against population data. The healthy BMI range (18.5–24.9) is the modern screening band. This calculator shows all three because they answer slightly different questions.
A worked example
A 5'10" man: Devine says about 161 lb, Robinson about 156 lb, and the healthy-BMI band runs roughly 129–173 lb. Notice the band is 44 pounds wide — that's the honest answer. A muscular 185-lb man at 5'10" can be in excellent health while sitting above every formula; a sedentary 150-lb man can carry too much visceral fat while looking "ideal" on paper.
What to actually do with this number
Treat the range as a sanity check, not a target etched in stone. Better health markers than scale weight: waist circumference (under roughly half your height in inches), strength and stamina trends, blood pressure, and lab work. If your weight sits far outside the band in either direction, that's worth a conversation with a doctor — who will look at the whole picture, not a 1974 dosing formula. Pick goals by how you feel and perform, and let the scale be one witness among several.
Frequently asked questions
Why do the formulas disagree with each other?
They were fit to different datasets and purposes decades apart. Disagreement of 5–10 pounds is normal and meaningless — that's why the BMI range is shown as a band, not a point.
Is ideal weight different for athletes?
Substantially. Muscle is dense, so strength athletes routinely exceed every formula while being lean. Body-fat percentage and waist measurement describe athletic bodies far better.
Does age change ideal weight?
Somewhat — modest weight gain into middle age appears benign, and very low weight becomes riskier in older adults (muscle loss). The formulas ignore age entirely; doctors don't.
What's a realistic pace to reach a healthy weight?
About 0.5–1% of body weight per week, via a moderate calorie deficit with adequate protein and resistance training. Slower is fine; sustainable beats fast every time.
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How ideal weight is calculated — the four main formulas
There is no single universally accepted formula for ideal body weight. This calculator uses the most widely referenced formulas, each developed by different researchers for different clinical contexts:
Devine formula (1974): Men: 50 kg + 2.3 kg per inch over 5 feet. Women: 45.5 kg + 2.3 kg per inch over 5 feet. Developed for drug dosing calculations in clinical medicine — still used for medication dosing today.
Robinson formula (1983): Men: 52 kg + 1.9 kg per inch over 5 feet. Women: 49 kg + 1.7 kg per inch over 5 feet. Developed as an improvement on Devine with slightly different coefficients.
Miller formula (1983): Men: 56.2 kg + 1.41 kg per inch over 5 feet. Women: 53.1 kg + 1.36 kg per inch over 5 feet. Produces slightly higher estimates than Devine or Robinson.
Hamwi formula (1964): Men: 48 kg + 2.7 kg per inch over 5 feet. Women: 45.4 kg + 2.3 kg per inch over 5 feet. Developed for clinical nutrition assessment — oldest of the common formulas.
All four produce estimates within 10–15 lb of each other for most heights, which reflects the genuine uncertainty in defining a single "ideal" weight for a given height.
Why these formulas have real limitations
Every ideal weight formula was developed primarily from data on white European adults, mostly men, in clinical or military settings. They do not account for age (older adults carry more risk at lower weights), frame size (a large-framed person at 6'2" and a small-framed person at the same height have very different healthy weights), ethnicity (Asian adults have different risk profiles at lower weights), or muscle mass (an athlete will far exceed the ideal weight range while being metabolically healthy).
The honest use of ideal weight formulas: they give you a ballpark. The BMI Calculator gives a similar range. Neither is a diagnosis or a goal — they are reference points that may or may not apply to your specific body composition.
Worked examples
Example 1 — Man, 5'11" (71 inches, 11 inches over 5 feet): Devine = 50 + (2.3 × 11) = 75.3 kg = 166 lb. Robinson = 52 + (1.9 × 11) = 72.9 kg = 161 lb. Range: approximately 161–166 lb, with healthy weight by BMI at 132–179 lb. The formulas suggest a specific target within the healthy BMI range.
Example 2 — Woman, 5'5" (65 inches, 5 inches over 5 feet): Devine = 45.5 + (2.3 × 5) = 57 kg = 126 lb. Robinson = 49 + (1.7 × 5) = 57.5 kg = 127 lb. BMI healthy range at 5'5": approximately 114–150 lb. The ideal weight formulas target the lower-middle portion of the healthy BMI range.
Frequently asked questions
Is there one ideal weight for my height?
No — the range of healthy weights for a given height spans 20–30 lb or more depending on frame size, muscle mass, age, and other factors. "Ideal weight" formulas give a midpoint estimate, not a precise target. A healthy BMI range (18.5–24.9) is a broader and more useful framework for most people.
Why do different formulas give different results?
Because they were developed by different researchers using different datasets and methods. The Devine formula was designed for drug dosing and has been widely adopted partly by convention, not because it is more accurate than the others. The differences between formulas are generally within 5–10 lb and reflect the inherent imprecision of height-based weight estimates.
What if I weigh more than my "ideal" weight but I am muscular?
Ideal weight formulas and BMI both have the same limitation with athletes: they cannot distinguish muscle from fat. A 200-lb person at 5'10" may be significantly above all ideal weight estimates while carrying 10% body fat. Body fat percentage is a far more meaningful metric for athletes. See the Body Fat % Calculator.
Are these formulas used in clinical medicine?
Yes — particularly the Devine formula, which is still used in pharmacology for calculating drug doses based on lean body weight in obese patients, and in respiratory therapy for ventilator settings. In these clinical contexts, the formula serves a specific dosing function, not a weight-loss goal-setting function.
Do ideal weight formulas work for children?
No. These formulas are validated for adults only. Children use growth charts comparing weight and height to age-specific percentiles. A pediatrician interprets these in context — not adult weight formulas.
Disclaimer: Ideal weight formulas are general reference tools, not medical standards. Consult a physician or registered dietitian for personalized weight management guidance.