Ideal Weight for Women — Female Healthy Weight Guide

What an Ideal Weight Formula Tells You

An ideal weight formula is a simple height-based equation that estimates a typical body weight associated with general wellness in large population samples. The word "ideal" is misleading — these formulas were never intended to give a single perfect number for each individual. They are historical reference points developed by researchers in the mid-to-late 20th century for specific evidence-based purposes. Think of them as three rough estimates from three different eras, not as personal targets written in stone.

Our calculator displays three formulas side by side: Devine (1974), Hamwi (1964), and Robinson (1983). Each was derived on a different population using different statistical approaches, which is why they disagree by several kilograms for the same height. Presenting all three together lets you see the plausible range of reference weights rather than pretending any one formula is uniquely correct. We also show a ±10 percent band around each estimate because human healthy weight naturally spans a meaningful range even at identical height and sex.

The Three Formulas

All three formulas use the same underlying structure: a baseline weight at 5 feet (152.4 cm) plus an additional weight per inch of height above 5 feet. The constants vary. For heights below 5 feet, the math works out to subtractions rather than additions, and in practice the formulas become increasingly unreliable the further below 5 feet you go.

Devine Formula — Primary. Where It Came From and Why It Matters

The Devine formula is the most commonly referenced ideal weight equation in modern medical literature and evidence-based practice, but it was never actually designed to tell anyone what they should weigh. Dr. B. J. Devine published his famous constants in 1974 for a very specific purpose: estimating lean body weight in adult men and women so that clinicians could calculate appropriate compounds proper amounts, most notably for the anticoagulant heparin and certain chemotherapeutic agents whose safe dosing window depends on the volume of distribution of lean tissue rather than total body weight.

Devine himself did not call the result an "ideal weight." He derived his constants from a small set of earlier studies that had measured lean body mass via isotope dilution in a limited sample of adults. Over time, clinicians and textbooks began to use Devine's lean body weight estimate as a convenient shorthand for a "reasonable weight" in conversation with adults, and from there it spread into online calculators and popular wellness writing. Today the Devine formula is the default primary estimate in this calculator precisely because it is the most-cited historical reference in peer-reviewed literature, not because anyone in 2025 believes it is a definitive ideal target.

The Devine formula has no frame-size adjustment. This is an important limitation. Two adults with identical height and sex but very different skeletal frame sizes will receive the same Devine estimate even though the larger-framed person can healthily carry several kilograms more than the smaller-framed person. Our UI presents a frame-size selector so you can mentally contextualize the results: if you know you have a broad, large build, the upper end of the ±10 percent band is a more appropriate reference than the midpoint. For small-framed individuals, the lower end of the band is typically a better personal reference.

Hamwi and Robinson — Historical Context

The Hamwi formula was developed in 1964 and was widely used in evidence-based nutrition through the 1970s and 1980s. It produces slightly higher estimates for men and slightly lower estimates for shorter women compared to Devine. It was the standard "ideal weight" taught in many nutrition schools for a generation and still appears in some older dietary software and insurance tables. The Hamwi formula is also the basis for the Broca index variants you still occasionally see in older European textbooks.

The Robinson formula was published in 1983 specifically for athletic populations after researchers observed that Devine and Hamwi estimates were often unrealistically heavy for shorter athletes and unrealistically light for taller athletes. Robinson used a lower per-inch coefficient for both sexes and a heavier baseline at 5 feet. For people 5 ft 10 and taller, Robinson typically gives the lightest of the three estimates, which is why it is sometimes preferred in strength and conditioning contexts where high lean mass at a given height is common.

Worked Example

For a 175 cm (5 ft 9 in) male. 5 ft 9 in is 9 inches over 5 ft. Devine: 50.0 + 2.3 × 9 = 70.7 kg. Hamwi: 48.0 + 2.7 × 9 = 72.3 kg. Robinson: 51.7 + 1.86 × 9 ≈ 68.4 kg. The three formulas span a range of roughly 4 kg for this example, which is entirely typical and illustrates why no single formula should be addressed as a definitive answer. Taking each result and applying a ±10 percent healthful band gives a wide but realistic reference window.

FAQ-Style Explanations

Why doesn't the calculator adjust Devine for frame size? The original Devine formula has no frame-size term. Adding one would make it no longer the Devine formula. Some textbooks and calculators do add ±10 percent adjustments for small, medium, and large frame, but these adjustments were not part of the original publication and are not standardized across sources. To keep the formulas historically faithful, we display the unmodified Devine number as the primary result and present the ±10 percent band beneath it as a general healthy range that naturally accounts for frame.

If all three formulas disagree, which one should I use? Start with the Devine estimate as the most common medical literature reference. Then compare your current weight, how you feel, how your clothes fit, and your energy levels. If you feel energetic, recover well, have regular menstrual cycles if applicable, sleep well, and have normal blood markers at a weight outside these formulas, that weight is fine for you. These are population references, not verdicts.

How does frame size affect healthy weight? Skeletal frame size — measured roughly by wrist circumference, elbow breadth, or shoulder width relative to height — creates a range of healthy weights that can differ by 8 to 12 kg between a small-framed and large-framed person of the same height and sex. Frame size has a genetic component and does not change in adulthood. People who are large-boned are not "overweight" simply because they exceed a formula midpoint. Use the ±10 percent band and your own common sense.

Known Limitations

• These formulas were never designed as standalone wellness tools. Devine was for compounds dosing, Hamwi was for older evidence-based practice, Robinson was for athletic populations.
• None of them account for body composition. Two people with identical height and sex can have the same weight but very different ratios of muscle to fat with very different metabolic health profiles.
• None of them account for age. Body composition changes with age, and a weight that is appropriate at 30 may or may not be appropriate at 70.
• Reliability degrades at heights far from the 5 ft baseline. The formulas become increasingly speculative for people shorter than roughly 150 cm or taller than roughly 195 cm.
• No prospective study has ever shown that matching one of these formula midpoints produces better long-term health outcomes than simply staying within a broad BMI Normal band and maintaining consistent physical activity and good nutrition.
• Not intended for use by children, adolescents, or pregnant or lactating individuals.

How Ideal Weight Formulas Work for Women

Ideal weight formulas were developed between the 1960s and 1980s as reference regressions based on height and sex. For women, three classic formulas are widely used: Devine (1974), Hamwi (1964), and Robinson (1983). All three start from a baseline weight for a 5-foot (152.4 cm) tall woman and add a fixed increment of weight for each additional inch of height above 5 feet. The differences between formulas reflect the populations and assumptions each was derived from — Devine was based on adult reference data, Hamwi was based on insurance actuarial tables, and Robinson was a revalidation on a broader modern sample. Use them as flexible reference ranges rather than exact targets.

The Three Classic Female Formulas

For example, a 165 cm (5'5") woman is 5 inches over 5 feet. The Devine formula gives 45.5 + 2.3 × 5 = 57.0 kg. Hamwi gives 45.5 + 2.2 × 5 = 56.5 kg. Robinson gives 49 + 1.7 × 5 = 57.5 kg. The three formulas span roughly 56 to 58 kg for this height — a useful reference range rather than a single target. Each formula also typically has a ±10 percent healthy reference range applied to account for natural variation in frame size, muscle mass, and body composition.

Female Height-Weight Reference Table

Smaller Frame and Body Composition

On average, women have a smaller skeletal frame and less muscle mass per unit of height than men, which is why the female formulas start from a lower baseline (around 45.5 kg versus 50 kg for men at 5 feet). Women also carry a higher proportion of essential fat — roughly 10 to 13 percent versus 2 to 5 percent for men — which contributes to scale weight without reflecting excess storage. That means a woman at the formula estimate may look and feel quite different from a man at his estimate, even at the same relative position. Use the ideal weight estimate alongside body fat percentage and waist-to-hip ratio rather than scale weight alone, since composition matters as much as total weight.

Frame Size Adjustment

All three formulas were originally published without frame size adjustment. As a practical refinement, you can apply a small ±5 percent adjustment based on your frame size: subtract 5 percent for a small frame, keep the base value for a medium frame, or add 5 percent for a large frame. A rough way to estimate frame size is the wrist measurement test — measure your wrist circumference just below the wrist bone with a flexible tape. For a 165 cm tall woman, a wrist below 15.5 cm suggests a small frame, 15.5 to 16.5 cm suggests medium, and above 16.5 cm suggests large. Frame adjustment is optional and approximate; use it to widen the reference range rather than to chase a precise number.

Why Ideal Weight Is a Range, Not a Number

The three classic formulas span a 1 to 3 kilogram range at most heights, which already reflects the natural variation in healthy adult women of the same height. Add the ±10 percent healthy reference range and the spread widens further. A 165 cm tall woman with a medium frame might reasonably carry anywhere from 50 to 63 kg depending on muscle mass, body composition, training history, and age. Use the ideal weight estimate as a flexible target zone to anchor longer-term planning, not as a finish line. The most useful interpretation is to compare your current weight against the range and notice the gap, then design a sustainable plan to close that gap if it is meaningful.

Practical Tips for Women

• Compare all three formulas side by side. If they agree within 1 to 2 kg, the answer is well-constrained for your height.
• Add the ±10 percent healthy reference range to widen the target zone. This accounts for natural variation in muscle mass, frame, and body composition.
• Pair the ideal weight estimate with BMI, body fat percentage, and waist-to-hip ratio. Each metric measures something different.
• If you are resistance-trained, expect your sustainable weight to sit at the upper end of the range or slightly above due to muscle mass.
• Re-evaluate the target annually or whenever your training focus shifts (gain, maintain, loss). Ideal weight is a long-term reference, not a moving daily target.