Ideal Body Weight Calculator
Calculate your ideal body weight from height, sex, and frame size using the Devine, Robinson, Hamwi, and Miller formulas, plus your healthy BMI weight range. Free, instant, no sign-up.
Ideal Body Weight Calculator
Units
Height
Formulas are calibrated for adults 5 ft (152 cm) and taller.
Sex
The ideal weight formulas model two sexes only. Results are estimates, not medical targets.
Body frame size
Wrap your thumb and middle finger around the opposite wrist to gauge frame size.
Formula comparison
Devine usually gives the lowest estimate and Miller the highest. The headline figure is their average.
Estimates only. Ideal weight formulas ignore muscle mass, body composition, age, and activity. They are a guideline, not a medical target. Talk to a clinician or registered dietitian before setting a weight goal, especially if you are pregnant, nursing, under 18, or managing a medical condition.
How the ideal body weight calculator works
The calculator needs three things: your height, your sex, and your body frame size. Height and sex feed the four ideal weight formulas directly. Each formula starts from a base weight at 5 ft (60 in) and adds a fixed amount for every inch above that, so a taller person lands at a higher ideal weight. You can switch between metric and imperial units, and the weight outputs follow your choice (kg or lb).
From those inputs the tool produces several numbers. The headline figure is the average of the Devine, Robinson, Hamwi, and Miller results, which gives one easy reference point instead of four. Alongside it sits the healthy BMI weight range, the spread of weights that put your BMI between 18.5 and 24.9. The body frame option then narrows the average into a personalized band: a small frame shifts toward the lower end, a large frame toward the higher end.
The four ideal weight formulas explained
Each formula has its own history and intent. The Hamwi formula (1964) is the oldest, a quick bedside method clinicians used to estimate weight at a glance. The Devine formula (1974) came next and was actually designed for calculating drug doses, not fitness goals; it remains the most widely cited and tends to give the lowest estimate. The Robinson formula (1983) refined Devine with gentler per-inch increases, and the Miller formula (1983), published the same year, usually returns the highest figure of the group.
Because the four were calibrated differently, they can disagree by several pounds for the same person. That spread is the point of showing all of them: it reminds you that ideal weight is an estimate, not a precise measurement. None of these formulas were built for athletes or general health goals. They came out of clinical and drug-dosing work, which is why the calculator averages them and pairs the result with a BMI range.
Ideal weight vs. healthy weight: what the number really means
An ideal weight figure is a single number, and that simplicity is also its weakness. The formulas know nothing about your body composition, muscle mass, frame, or activity level. A muscular person can sit well above their calculated ideal weight and still be in excellent health, while someone exactly at the number can carry too much body fat. This is why the calculator also shows the healthy BMI range rather than insisting on one figure.
A healthy weight is better understood as a band than a point. Looking at a few numbers together beats chasing a single one: read the ideal weight estimate next to your BMI range, factor in your frame, and consider how you actually look and feel. Treat the calculator as a guideline that gives you a sensible starting reference, then let real-world progress and, where useful, professional advice shape the goal.
Using a target weight inside a 75-day challenge
Once you have a reference weight, the next step is reaching it at a sustainable pace. A 75-day challenge works well as a window for this: long enough to show real change, short enough to stay focused. Set a realistic goal inside your healthy range rather than the most flattering formula result, and plan a steady rate of change instead of a crash. The calorie deficit calculator can help you size the gap, and the 75-day challenge calculator maps out the timeline.
The number on the scale moves unevenly, so track the trend, not the daily reading. Reset75 handles this with a daily Weigh-In task, progress photos, and trend charts across a 75-day or 75 Soft challenge, all with no account required. Logging weigh-ins steadily and watching the line over weeks is far more useful than fixating on hitting one exact figure.
Frequently Asked Questions
Common questions about ideal body weight calculator
How is ideal body weight calculated?
Ideal body weight formulas use your height and sex. Each starts from a base weight at 5 ft (60 in) and adds a set amount for every inch above that. This calculator runs four formulas (Devine, Robinson, Hamwi, and Miller), averages them for a headline figure, and also shows the healthy weight range from a BMI of 18.5 to 24.9. The body frame option then narrows the average into a personalized band.
What is the difference between the Devine, Robinson, Hamwi, and Miller formulas?
All four estimate ideal weight from height and sex, but they were calibrated differently. Devine (1974) was built for drug dosing and tends to give the lowest figures. Robinson (1983) refined Devine with a gentler per-inch increase. Hamwi (1964) is the earliest bedside method. Miller (1983) usually returns the highest estimate. Averaging them smooths out the spread.
How much should I weigh for my height?
There is no single correct number. For most adults, a weight that places your BMI between 18.5 and 24.9 is considered healthy, which is why this tool shows that full range. The averaged ideal weight figure sits inside that band as a convenient reference point. Use the healthy range, not one exact number, as your target.
Is ideal body weight the same as a healthy BMI?
No. Ideal body weight formulas return a single estimated number, while a healthy BMI describes a range of weights (a BMI of 18.5 to 24.9). The ideal weight figure usually falls inside the healthy BMI range. The BMI range is the more medically grounded reference because it acknowledges that several weights can be healthy at one height. You can explore it further with the BMI calculator.
How do I find my body frame size?
The easiest check uses your wrist. Wrap your thumb and middle finger around the opposite wrist: if they overlap, you likely have a small frame; if they just touch, a medium frame; if they do not meet, a large frame. Frame size shifts the ideal weight band by roughly 10 percent in either direction.
Does ideal body weight account for muscle mass?
No. The formulas only use height and sex, so they cannot tell muscle from fat. A very muscular person can sit above their calculated ideal weight and still be healthy, while someone at the ideal number can carry excess body fat. Pair the estimate with body composition or progress photos for a fuller picture.
Why don't these formulas use age?
The four core ideal weight formulas (Devine, Robinson, Hamwi, and Miller) are functions of height and sex only. Adding an age field would imply it changes the result when it does not. Age does affect body composition and metabolism, so consider it when you read the estimate, but it is not part of the math.
Is the ideal body weight calculator accurate?
It is accurate at what it does: applying published formulas. The limitation is the formulas themselves. They were built for clinical use, not fitness goals, and ignore muscle, body fat, and activity. Treat the output as a guideline and a starting reference, not a medical target. For a personalized goal, talk to a clinician or registered dietitian.