"How much should I weigh?" is one of the most common health questions. The answer isn't a single number — it's a range that depends on your height, gender, body frame, muscle mass, and age. This calculator uses four established medical formulas (Devine, Robinson, Miller, and Hamwi) to give you a comprehensive ideal weight range, avoiding the oversimplification of relying on any single method.
## The Four Formulas Explained **Devine Formula (1974)**: Originally developed for drug dosage calculations, this became the most widely cited ideal weight formula. Men: 50 + 2.3 kg per inch over 5 feet. Women: 45.5 + 2.3 kg per inch over 5 feet. **Robinson Formula (1983)**: A refinement of Devine with slightly different coefficients. Men: 52 + 1.9 kg per inch over 5 feet. Women: 49 + 1.7 kg per inch over 5 feet. **Miller Formula (1983)**: Produces higher ideal weights than Devine, more suitable for people with larger frames. Men: 56.2 + 1.41 kg per inch over 5 feet. Women: 53.1 + 1.36 kg per inch over 5 feet. **Hamwi Formula (1964)**: The oldest of the four, still widely used in clinical nutrition. Men: 48 + 2.7 kg per inch over 5 feet. Women: 45.4 + 2.2 kg per inch over 5 feet.
## Why Use Multiple Formulas? No single formula captures the full range of healthy body weights. Body frame size (small, medium, large), muscle mass, bone density, and ethnic variation all influence ideal weight. By averaging four formulas, you get a more reliable target range that accounts for these differences. A practical approach: if all four formulas cluster tightly (within 5 lbs), you have a strong target. If they diverge significantly, your frame size likely differs from the "medium frame" assumption — adjust toward the formula that best matches your build.
## Ideal Weight vs. BMI BMI defines a "normal weight" range (18.5–24.9) that translates to a wide weight range for any given height. For example, a 5'10" person has a healthy BMI weight range of 129–174 lbs — a span of 45 pounds. Ideal weight formulas narrow this range to a more actionable target, though they still represent guidelines rather than absolutes. The best approach is to combine ideal weight formulas with BMI range, body fat percentage, and waist circumference for a comprehensive health assessment.
This tool is most useful for tracking trends rather than obsessing over a single data point. Run the calculation monthly with consistent measurement conditions to see whether your metric is moving in the right direction.
The most common mistake is treating the result as a precise measurement rather than an evidence-based estimate. All body metric calculators have margins of error — use the result as a tracking baseline, not a clinical diagnosis.
A personal trainer uses the calculator with a new client to set a measurable starting point. Re-running the calculation at 4-week intervals provides an objective progress metric that supports motivation and programme adjustments.
Ideal Weight Formulas
Devine: Men 50 + 2.3×(in−60) kg | Women 45.5 + 2.3×(in−60) kg
Robinson: Men 52 + 1.9×(in−60) | Women 49 + 1.7×(in−60)
Miller: Men 56.2 + 1.41×(in−60) | Women 53.1 + 1.36×(in−60)
Hamwi: Men 48 + 2.7×(in−60) | Women 45.4 + 2.2×(in−60)
All formulas use inches over 60 (5 feet) as the height variable. Results in kg — multiply by 2.205 for lbs.
A 5'8" (68 inches) male wants to know his ideal weight.
Result: Ideal weight range: 148–154 lbs (67–70 kg) for a medium-frame male
No single formula is definitively best. Averaging Devine, Robinson, Miller, and Hamwi gives the most reliable range for the general population.
It depends on gender, frame size, and muscle mass. For a 5'8" medium-frame male, ideal weight is approximately 145–165 lbs. For a 5'4" female, approximately 120–140 lbs.
Yes. Large-framed individuals can add ~10% to formula results; small-framed individuals subtract ~10%. Measure frame size by wrapping your thumb and middle finger around your wrist.
Absolutely. Athletes with high muscle mass may weigh 10–30 lbs above formula-based ideal weight while having excellent health markers and low body fat.
No. Being too thin carries health risks including muscle loss, weakened immunity, hormonal disruption, and bone density loss. Aim for the middle of the range.
CalcPlanet – Free Online Calculators
725+ free calculators and 108 tools for math, money, health, and everyday life. Instant results, verified formulas, no sign-up.
By CalcPlanet Editorial · Reviewed against our Editorial Standards and Formula Sources.
CalcPlanet calculators are free, privacy-first, and formula-reviewed.
Editorial Standards · Formula Sources · Privacy · Terms · Contact
