Ideal Weight Calculator — Your Ideal Body Weight by 4 Formulas
Four classic medical formulas — Devine, Robinson, Miller and Hamwi — each turn your height into an ideal body weight.
Your details
These formulas were designed for adults. They do not apply to children or teenagers, and not during pregnancy.
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Ideal weight
- Four classic formulas — Devine, Robinson, Miller and Hamwi — each give an ideal weight for your height and sex; where they cluster is the honest answer.
- At the defaults — a man of 175 cm with a medium frame — Devine gives 70.5 kg and the four formulas average 70.0 kg, against a BMI healthy range of 56.7–76.3 kg.
- Frame size adjusts every formula: a small frame reads about 10% lower and a large frame about 10% higher.
- Four formulas, one scale
- Keep exploring
- How it works
- The formulas behind ideal weight
- Go deeper
- What is my ideal weight?
- The four formulas, exactly as published
- The healthy weight range cross-check
- How much should I weigh at 5’9″ or 5’7″?
- Frame size: the ±10% convention
- What “ideal” does not mean
- Related guides
- Frequently asked questions
- Related calculators
Four classic medical formulas — Devine, Robinson, Miller and Hamwi — each turn your height into an ideal body weight. See all four side by side, their average, and the BMI healthy range for the same height.
Four formulas, one scale
The green band is the BMI healthy range for your height; the markers are the four formulas. Where they cluster is the honest answer.
Keep exploring
Three companion tools for health and energy.
How it works
Three steps to your ideal-weight neighbourhood.
Choose sex and units
Each formula has a male and a female version, and all four are built on inches over 5 feet — the toggle just changes how you type your height.
Enter your height
Height is the only input: every formula starts from a base weight at 5 feet and adds a fixed amount for each inch above it.
Read the cluster, not a point
Four formulas, their average, and the BMI healthy range together. Where the four agree is a sensible neighbourhood for an average adult frame.
The formulas behind ideal weight
All four formulas share one shape: a base weight at exactly 5 feet, plus a per-inch addition for every inch of height above that. They differ only in the two constants — which is why they land a few kilograms apart, and why no single one of them deserves blind trust.
The constants (men / women):
| Formula | Base at 5 ft | Per inch over | Origin |
|---|---|---|---|
| Devine (1974) | 50.0 / 45.5 kg | 2.30 / 2.30 kg | Drug dosing — the most widely used today |
| Robinson (1983) | 52.0 / 49.0 kg | 1.90 / 1.70 kg | A gentler revision of Devine |
| Miller (1983) | 56.2 / 53.1 kg | 1.41 / 1.36 kg | Higher base, slower growth — suits shorter heights |
| Hamwi (1964) | 48.0 / 45.5 kg | 2.70 / 2.20 kg | The oldest of the four, from diabetes diet planning |
Worked example — man, 175 cm: 175 cm = 68.90 in, so 8.90 inches over 5 ft. Devine: 50 + 2.3 × 8.90 = 70.5 kg · Robinson: 52 + 1.9 × 8.90 = 68.9 kg · Miller: 56.2 + 1.41 × 8.90 = 68.7 kg · Hamwi: 48 + 2.7 × 8.90 = 72.0 kg. Average: 70.0 kg.
Worked example — woman, 165 cm: 165 cm = 64.96 in, so 4.96 inches over 5 ft. Devine: 45.5 + 2.3 × 4.96 = 56.9 kg · Robinson: 49 + 1.7 × 4.96 = 57.4 kg · Miller: 53.1 + 1.36 × 4.96 = 59.8 kg · Hamwi: 45.5 + 2.2 × 4.96 = 56.4 kg. Average: 57.7 kg.
The BMI healthy range alongside uses the standard band: 18.5 × height² to 24.9 × height² (height in metres). At 175 cm that is 56.7–76.3 kg — noticeably wider than the formulas’ cluster, because a range answers a different question than a point estimate.
Go deeper
Why the formulas disagree, and which number deserves your trust.
The formulas were built for different jobs, in different decades, from different patient groups:
- Different purposes: Devine was designed to scale drug doses, Hamwi for diabetes meal planning. Neither set out to define beauty or athletic performance.
- Different bases: Miller starts highest at 5 ft (56.2 kg for men) but adds least per inch, so it reads high for shorter people and low for taller ones; Hamwi does the opposite.
- They converge in the middle: around average heights the four sit within about 3 kg of each other — that agreement is the signal. At extremes of height they spread out, which is the formulas quietly admitting their limits.
- What none of them know: your frame size, muscle mass, or where you carry weight. Two healthy people of the same height can legitimately differ by 10 kg.
They answer different questions, and the honest answer is “both, loosely”:
- The formulas give a point: one number per height, easy to remember and useful as a rough centre of gravity — but a point pretends to a precision bodies do not have.
- BMI gives a range: at 175 cm the healthy band spans almost 20 kg (56.7–76.3 kg). Wide, but it honestly reflects how much healthy bodies vary.
- A practical reading: if all four formulas cluster comfortably inside your BMI range — as they do at most heights — that cluster is a reasonable neighbourhood to aim near. Outside it, trust the range and a clinician over any single formula.
- Muscle changes everything: strength athletes routinely sit above every formula while lean and healthy. Formulas cannot see composition; a waist measurement or body-fat estimate adds what they miss.
What is my ideal weight? Read the cluster, not a single number
The question behind this page, answered the way the formulas themselves answer it: as a small neighbourhood.
“What is my ideal weight” sounds like a question with one answer. It has four — one per formula — and the honest reply to “what should my weight be” is the small range those four span, checked against the healthy range for your height. Around average heights they agree within about 3 kg, and that agreement is worth more than any single figure: four derivations landing in the same neighbourhood.
Two worked readings show the pattern. The ideal weight for 5’5 female readers (165.1 cm) comes out at Devine 57.0 kg, Robinson 57.5 kg, Miller 59.9 kg and Hamwi 56.5 kg — a cluster of 56.5–59.9 kg inside a healthy range of 50.4–67.9 kg. The ideal weight for 5’6 female readers (167.6 cm) runs a little higher: 58.7–61.3 kg across the four, inside a healthy range of 52.0–70.0 kg.
The same shape holds for the ideal weight for men: at 5’10” (177.8 cm) the four formulas cluster at 70.3–75.0 kg, inside a healthy range of 58.5–78.7 kg. And one variable is missing from every formula, for the ideal weight for women and men alike: age. A search for a “how much should i weigh for my height and age chart” lands here because the heights are charted — but no formula takes an age input; the last FAQ below explains what changes with age instead.
The four formulas, exactly as published
Each formula with its constants as its author published them — Hamwi (1964), Devine (1974), Robinson (1983), Miller (1983).
Every formula on this page is one line: a base weight at exactly 5 feet, plus a fixed addition for each inch above it (subtracted below 5 feet). Here is each one as published, with the metric constants this calculator runs beside it:
| Formula | Men, as published | Women, as published |
|---|---|---|
| Hamwi (1964) | 106 lb + 6 lb per inch | 100 lb + 5 lb per inch |
| Devine (1974) | 50 kg + 2.3 kg per inch (110 lb + 5.1 lb) | 45.5 kg + 2.3 kg per inch (100 lb + 5.1 lb) |
| Robinson (1983) | 52 kg + 1.9 kg per inch (115 lb + 4.2 lb) | 49 kg + 1.7 kg per inch (108 lb + 3.8 lb) |
| Miller (1983) | 56.2 kg + 1.41 kg per inch (124 lb + 3.1 lb) | 53.1 kg + 1.36 kg per inch (117 lb + 3.0 lb) |
The calculator runs the rounded metric constants — Hamwi as 48 kg + 2.7 kg (men) and 45.5 kg + 2.2 kg (women) — so a pound-perfect conversion of the 1964 original can differ from the tool’s output by a tenth of a kilogram. That rounding is inherited from decades of clinical printing.
Worked example — man, 5’10” (70 inches, so 10 inches over 5 ft): Devine: 50 + 2.3 × 10 = 73.0 kg · Robinson: 52 + 1.9 × 10 = 71.0 kg · Miller: 56.2 + 1.41 × 10 = 70.3 kg · Hamwi: 48 + 2.7 × 10 = 75.0 kg. Average: 72.3 kg.
Worked example — woman, 5’5″ (65 inches, so 5 inches over): Devine: 45.5 + 2.3 × 5 = 57.0 kg · Robinson: 49 + 1.7 × 5 = 57.5 kg · Miller: 53.1 + 1.36 × 5 = 59.9 kg · Hamwi: 45.5 + 2.2 × 5 = 56.5 kg. Average: 57.7 kg.
The healthy weight range: the cross-check beside the formulas
The formulas give points. The BMI band gives the range those points should land inside.
Read as a healthy weight calculator, this page carries a second instrument beside the four formulas: the healthy range, 18.5 to 24.9 times your height in metres squared — the adult band the CDC and WHO publish. Where a formula says “about here”, the band says “anywhere in here is a healthy weight for your height” — at most heights a span of 14–24 kg.
The healthy weight chart below puts the two side by side. The healthy weight for men at 5’10”, for instance, is the band 58.5–78.7 kg — while the four formulas pick out 70.3–75.0 kg inside it. At average heights the cluster sits comfortably within the band. The edges are where they part company: at 4’10” the formulas spread 9.5 kg apart (40.9–50.4 kg) against a band 13.9 kg wide, and at 6’4″ they spread 12.4 kg (78.8–91.2 kg) against a band 23.8 kg wide. The band widens with the square of height; the formulas only add per inch — so the taller or shorter you are, the more the range deserves your trust over any point.
| Height | Sex | Four formulas (cluster) | Healthy range (BMI 18.5–24.9) |
|---|---|---|---|
| 4’10” (147.3 cm) | Women | 40.9–50.4 kg | 40.2–54.0 kg |
| 5’5″ (165.1 cm) | Women | 56.5–59.9 kg | 50.4–67.9 kg |
| 6’0″ (182.9 cm) | Women | 69.4–73.1 kg | 61.9–83.3 kg |
| 5’5″ (165.1 cm) | Men | 61.5–63.3 kg | 50.4–67.9 kg |
| 5’10” (177.8 cm) | Men | 70.3–75.0 kg | 58.5–78.7 kg |
| 6’4″ (193.0 cm) | Men | 78.8–91.2 kg | 68.9–92.8 kg |
The full BMI picture — categories, and what your own BMI is — lives on the BMI Calculator; this page borrows only the band.
How much should I weigh at 5’9″ or 5’7″?
Two of the most asked heights, answered from the same four formulas as the calculator above — for adults, with the healthy range beside each answer.
If you are 5’9″, how much should you weigh? For a man, the four formulas cluster at 68.9–72.3 kg (151.9–159.4 lb), averaging 70.2 kg (154.8 lb). For a woman of the same height, they cluster at 64.3–66.2 kg (141.8–145.9 lb), averaging 65.3 kg (144.0 lb). At 5’7″, the ideal weight in kg is 65.3–66.9 kg for a man (average 66.1 kg) and 60.9–62.6 kg for a woman (average 61.5 kg). Every figure below comes from the calculator’s own constants, so typing the height into the tool above reproduces it exactly.
| Height | Sex | Four formulas (cluster) | Average | Healthy range (BMI 18.5–24.9) |
|---|---|---|---|---|
| 5’9″ (175.3 cm) | Men | 68.9–72.3 kg | 70.2 kg | 56.8–76.5 kg |
| 5’9″ (175.3 cm) | Women | 64.3–66.2 kg | 65.3 kg | 56.8–76.5 kg |
| 5’7″ (170.2 cm) | Men | 65.3–66.9 kg | 66.1 kg | 53.6–72.1 kg |
| 5’7″ (170.2 cm) | Women | 60.9–62.6 kg | 61.5 kg | 53.6–72.1 kg |
How to calculate healthy weight beside any formula result: take the BMI healthy band, 18.5 to 24.9 times your height in metres squared. At 5’9″ (1.7526 m) that gives 56.8–76.5 kg; at 5’7″ (1.7018 m) it gives 53.6–72.1 kg. The band is the same for men and women at the same height, which is why both rows share it. The formulas themselves each follow one shape — a base weight at exactly 5 feet, plus a fixed amount for every inch above it — with the published constants listed in full in the formulas section above: Devine, Robinson, Miller and Hamwi, each with its own male and female version.
Frame size moves every figure by the same convention used by the calculator’s frame toggle: about 10% lower for a small frame, about 10% higher for a large one. On the 5’9″ man above, the 70.2 kg average becomes 63.2 kg for a small frame and 77.2 kg for a large one — still inside the 56.8–76.5 kg healthy range at the small end, and a reminder that the cluster is a neighbourhood to aim near, not a single number to hit. These examples are for adults: the formulas were not designed for children or teenagers.
Frame size: the ±10% convention
The one adjustment the formulas’ own tradition allows — and it is a convention, not a measurement.
The four formulas were published for a medium frame. The dietetics tradition that grew up around Hamwi’s rule adjusts them by a flat tenth: subtract 10% for a small frame, add 10% for a large one. Frame is judged at the wrist — wrap thumb and middle finger around the opposite wrist: overlapping suggests small, just touching medium, a gap large. A rough bedside convention, labelled as one.
The calculator’s frame toggle applies exactly that convention to all four outputs. On the 5’5″ woman worked above, Devine’s 57.0 kg becomes 51.3 kg for a small frame and 62.7 kg for a large one — a swing wider than the gap between the formulas themselves.
What “ideal” does not mean
A reference point from clinical arithmetic — not a verdict on a body.
None of the four formulas was built to judge health. Devine’s was published to scale drug doses; Hamwi’s to plan diabetes diets; Robinson and Miller refitted the idea to population data. An “ideal weight” from any of them is a dosing-era reference point that escaped the clinic — useful as a neighbourhood, meaningless as a pass-or-fail line. The healthy range beside it spans roughly 14–25 kg precisely because healthy bodies of one height legitimately vary that much.
Two groups should read every output with particular care. Strength athletes routinely sit above all four formulas while lean, because the formulas cannot see muscle. And older adults tend to lose muscle while keeping weight — the same number on the scale, a different body underneath. For both, composition measures — waist size, or the estimate on the Body Fat Calculator — say what a height-only formula cannot. Nothing on this page prescribes eating or exercise; it estimates and explains. And the standing boundary from the form above still applies: these are adult formulas, not for children, teenagers or pregnancy.
Related guides
The chart form of this calculator, computed row by row.
Men, women, and the same four formulas
The sex difference is a few kilograms. The formula spread can be larger.
All four formulas give different answers for men and women at the same height, because the base weights and per-inch additions differ by sex. At 5 feet 9 inches, Devine gives 70.7 kg for a man and 66.2 kg for a woman, Robinson 69.1 and 64.3, Miller 68.9 and 65.3, and Hamwi 72.3 and 65.3: a sex difference of 3 to 7 kg depending on the formula. At taller heights the formula spread itself, up to 7.3 kg for men at 6 feet, can exceed the sex difference, which is a useful sense of proportion. No formula takes age, frame, muscle, or body composition into account, so the cluster is a reference neighbourhood, and the frame-size convention allows plus or minus 10% around the formula answers for small and large frames, as a rough acknowledgement of build rather than a precise correction.
Units deserve the same care as the formulas. The calculator works in kilograms or pounds and in centimetres or feet and inches, and the per-inch additions in the table above are the metric figures with imperial equivalents alongside: Devine adds 2.3 kg or 5.1 lb per inch for both sexes, Robinson 1.9 kg or 4.2 lb for men and 1.7 kg or 3.8 lb for women, Miller 1.41 kg or 3.1 lb for men and 1.36 kg or 3.0 lb for women, and Hamwi 2.7 kg or 6 lb for men and 2.2 kg or 5 lb for women. Enter height in the unit you measured it in, check the cluster against the BMI healthy range for the same height, and read the two new guides for the full comparison and the life-course reading.
Frequently asked questions
Quick answers about ideal body weight.
What is my ideal weight for my height?
No single published number exists — the honest answer is the small cluster the four formulas form. At this page’s default, a man of 175 cm, they give Devine 70.5 kg, Robinson 68.9 kg, Miller 68.7 kg and Hamwi 72.0 kg: a cluster of 68.7–72.0 kg averaging 70.0 kg, inside a healthy range of 56.7–76.3 kg. Enter your own height above and read the result the same way.
What are the four ideal weight formulas?
Hamwi (1964), Devine (1974), Robinson (1983) and Miller (1983). All four share one shape — a base weight at exactly 5 feet plus a fixed addition per inch above it — and differ only in those two constants. The formulas section above prints each one exactly as published, in pounds and kilograms.
Which ideal weight formula is most accurate?
None has been shown most accurate for an individual, and they were not designed to be: Devine was published for scaling drug doses, Hamwi for diabetes diet planning. Devine is the most widely used, which is why it headlines this calculator — but the agreement of all four beats any one of them. Where they spread apart, at very short or tall heights, trust the healthy range more.
What is a healthy weight for a 5’5″ woman?
By the BMI healthy band, 50.4–67.9 kg at 5’5″ (165.1 cm). The four formulas cluster inside it at 56.5–59.9 kg — Devine 57.0 kg, Robinson 57.5 kg, Miller 59.9 kg and Hamwi 56.5 kg — in the band’s lower-middle, which is where point formulas usually land.
What is a healthy weight for a 5’10” man?
By the BMI healthy band, 58.5–78.7 kg at 5’10” (177.8 cm). The four formulas cluster inside it at 70.3–75.0 kg — Devine 73.0 kg, Robinson 71.0 kg, Miller 70.3 kg and Hamwi 75.0 kg.
Why do the formulas give different answers?
Each was fitted to different people, in a different decade, for a different job — drug dosing, diabetes diets, clinical nutrition — and each chose a different base weight and per-inch addition. Around average heights those choices nearly cancel and the four agree within about 3 kg; at the extremes they spread, which is the formulas quietly marking their own limits.
What is the Devine formula?
Published by B. J. Devine in 1974 to scale drug doses by body size: men take 50 kg at 5 feet plus 2.3 kg for every inch over; women take 45.5 kg plus the same 2.3 kg per inch. It is the most widely used of the four — which is why it headlines this calculator — but most used is not the same as most accurate for you.
Does frame size change my ideal weight?
By convention, yes — a flat 10% either way. The formulas assume a medium frame; the tradition around them subtracts 10% for a small frame and adds 10% for a large one, judged roughly at the wrist. On Devine’s figure for a 5’5″ woman, that turns 57.0 kg into 51.3 kg (small) or 62.7 kg (large). The calculator’s frame toggle applies the same adjustment to all four formulas. Treat it as a convention, not a measurement.
Is ideal body weight the same as a healthy BMI range?
No. An ideal-weight formula returns one point for your height; a healthy BMI range returns a band — 18.5 to 24.9 times height squared — that spans roughly 14–25 kg depending on height. At average heights the formulas’ cluster sits inside the band, which is the sensible way to read them together: the cluster as a neighbourhood inside the range, not a replacement for it.
What should I weigh for my height and age?
Your height, yes — your age enters none of the four formulas. A 25-year-old and a 65-year-old of the same height and sex get identical outputs here, because no published formula takes an age input. What changes with age is composition — muscle mass tends to fall and fat distribution shifts — which is why the healthy range, a waist measurement and body composition matter more, not less, as the years add up.
Do ideal weight formulas differ for men and women?
Yes. Each formula uses different base weights and per-inch additions by sex. At 5 feet 9 inches, Devine gives 70.7 kg for a man and 66.2 kg for a woman, and the other three formulas show similar gaps of 3 to 7 kg. The BMI healthy range, by contrast, is identical for both sexes.
Should I use kilograms or pounds for ideal weight?
Whichever unit you measured your height in. The formulas are identical in either system: Devine, for example, adds 2.3 kg or 5.1 lb per inch above 5 feet. Mixing systems is the commonest arithmetic error, so enter height and read the answer in one system throughout.
What is the frame size adjustment?
A convention, not a measurement: plus or minus 10% around the formula answers for large and small frames, classified roughly by wrist circumference relative to height. It acknowledges that build moves healthy weight by kilograms at a fixed height. Treat it as a reminder that the cluster is a neighbourhood, not a corrected prescription.
Does ideal weight change with age?
The formula answers do not change, because no published ideal-weight formula takes an age input. What changes with age is composition, muscle, bone, and fat distribution, which the formulas cannot see. Read the cluster with waist, strength, and trend alongside, at every age.
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More tools for health and fitness numbers.
Disclaimer
This calculator is for general information only and is not medical advice. Ideal-weight formulas are population averages from decades-old clinical data; beyond the rough frame-size adjustment above, they do not account for muscle mass, ethnicity or medical history, and they are not a health target. If you are concerned about your weight, talk to a qualified clinician.