Ideal Weight Calculator

When to use this

The question "what should I weigh?" has no single correct answer, and that is precisely why this calculator shows you results from four different medical formulas rather than just one. The Devine, Robinson, Miller, and Hamwi formulas were each developed in different decades for different clinical purposes, and they can disagree by 10–20 pounds for the same person. Seeing the range gives you a more honest picture than any single number could.

These formulas are most commonly used in clinical settings for medication dosing (many drug doses are calculated based on ideal body weight), ventilator settings, and nutritional assessments. If a doctor has mentioned your "ideal body weight," they were likely using the Devine formula — it is the most widely referenced in medical practice, even though it was originally designed for drug calculations, not as a health recommendation.

For personal use, the healthy BMI weight range (the range of weights that would place your BMI between 18.5 and 24.9) is often more useful than any single formula. It gives you a window — typically a 30-to-40-pound span — rather than a single target, which better reflects the reality that healthy bodies come in many shapes. Frame size adjustments in this calculator further refine the range based on whether you have a small, medium, or large skeletal frame.

Good to know

These formulas are height-based, not body-based. All four formulas use only height and sex as inputs. They know nothing about your muscle mass, bone density, body fat distribution, age, or fitness level. A sedentary 5'10" person and a competitive 5'10" athlete get the same "ideal weight," which should tell you how loosely to hold these numbers.

The formulas disagree — and that is the point. Devine tends to produce the lowest estimates for women, Miller the highest. Robinson and Hamwi fall in between. Rather than picking the one you like best, look at the full range. If all four formulas agree you are well above or below the range, that is more meaningful than any single result.

Frame size matters more than people realize. Someone with a large frame (wider wrists, broader shoulders, thicker bones) genuinely weighs more at the same height than a small-framed person — and should. Wrist circumference is the simplest proxy for frame size: below 6.5 inches for men or 5.5 inches for women typically indicates a small frame.

"Ideal" is a loaded word. These formulas describe statistical midpoints, not aspirational targets. Your healthiest weight depends on factors no formula can capture — how you feel, how you function, your bloodwork, your relationship with food, and your individual medical history. Use the numbers as reference points, not verdicts.

Quick Reference

Formula	Year	Men (base + per inch over 5')	Women (base + per inch over 5')
Devine	1974	110 lb + 5.1 lb/in	100 lb + 5.1 lb/in
Robinson	1983	114 lb + 4.2 lb/in	108 lb + 3.5 lb/in
Miller	1983	123 lb + 3.1 lb/in	119 lb + 3.5 lb/in
Hamwi	1964	106 lb + 6.0 lb/in	100 lb + 5.0 lb/in