⚖️ Ideal Weight Calculator
By Shihab Mia · Reviewed by ToolNimba Editorial Review, health content · Updated 2026-07-29
This calculator gives a general estimate for healthy adults and is not medical advice. Ideal weight depends on muscle mass, frame size, age and health conditions, and the formulas here do not apply to children, pregnant people or athletes. Talk to a doctor or registered dietitian before setting a weight goal.
The Devine formula gives one reference figure; the BMI range gives a healthy band for your height.
This ideal weight calculator estimates a healthy weight for your height using two trusted methods side by side. Enter your sex and height in metric or imperial units. You will get a single reference figure from the Devine formula (the equation clinicians use for medication dosing) and a healthy weight range based on a BMI of 18.5 to 24.9. Use them together: the Devine number is a midpoint, while the BMI band shows the realistic range of healthy weights for your height.
What is the Ideal Weight Calculator?
There is no single correct body weight, which is why the idea of an ideal weight is best treated as a guide rather than a target to hit exactly. Two people of the same height can both be perfectly healthy at quite different weights depending on how much muscle they carry, their frame size and their body composition. The figures on this ideal weight calculator are population averages, not a personal prescription.
The Devine formula was published in 1974 and was originally designed to help calculate drug doses, not to set diet goals. It starts from a base weight at a height of 5 feet (50 kg for men, 45.5 kg for women) and adds 2.3 kg for every inch above that. Because it is built around inches over 5 feet, it works best for adults of roughly average height and can drift, or even extrapolate below its intended range, for people who are very short or very tall. This calculator flags that case for you when it happens. Either way, that single number is useful as a quick reference point, but it gives no sense of the range that is still healthy.
That is where the BMI-based range adds value. Body Mass Index divides weight in kilograms by height in metres squared, and a BMI between 18.5 and 24.9 is widely classed as a healthy weight. Rearranging the formula gives a weight band for any height: multiply 18.5 and 24.9 by your height in metres squared. The result is a span of several kilograms rather than one figure, which better reflects the truth that health sits across a range. BMI has real limits (it cannot tell muscle from fat), so use these numbers as a starting point and judge them alongside how you feel, your fitness and advice from a professional.
The Devine formula is not the only ideal body weight formula in use. Three other height-based formulas turn up across clinical references and other ideal weight calculators: the Hamwi formula (1964), and the Robinson (1983) and Miller (1983) formulas, all built the same way, a base weight at 5 feet plus a fixed amount per inch above that. They were developed independently by different researchers for similar clinical purposes, and for the same height they typically land within a few kilograms of each other and of the Devine figure. The comparison table below lists all four side by side so you can see how much they agree, and where they differ.
Several real factors shift what counts as a healthy weight for an individual beyond height and sex. Frame size, often estimated from wrist circumference, means two people of identical height can carry noticeably different amounts of lean mass at a healthy body fat percentage. Age matters too: none of the Devine, Robinson, Miller or Hamwi formulas adjust for age, yet adults naturally lose some muscle and gain some fat as they get older (a process called sarcopenia), so the same reference number can represent a different body composition at 25 and at 65. Genetics and ethnicity also influence where health risk actually starts to rise on a BMI scale, which is one reason several national health bodies use lower BMI cut-offs for some Asian populations.
In practice, use this calculator as a starting reference, not a finish line. Clinicians and pharmacists still use ideal body weight, and a related figure called adjusted body weight, to help calculate some medication doses for patients whose actual weight is well above their ideal weight; that is a technical, professional use case and not a personal diet target. If you are setting your own goal weight, it is more useful to combine this range with how your clothes fit, your energy levels, your strength and, ideally, a conversation with a doctor or registered dietitian, than to chase one specific number.
When to use it
- Getting a realistic, healthy weight range for your height before setting a fitness or diet goal.
- Checking the Devine "ideal body weight" figure that clinicians use as a reference for some medication doses.
- Comparing a single reference weight against the wider healthy band so you do not chase one exact number.
- Preparing figures to discuss with a doctor or dietitian before starting a weight loss or muscle gain plan.
- Nursing and pharmacy students, or clinicians, double checking a quick ideal body weight reference for a dosing calculation.
- Athletes and lifters sanity checking their weight against a general population formula and understanding why they may sit above it.
How to use the Ideal Weight Calculator
- Choose metric (cm) or imperial (ft and in) units.
- Select your sex, since the Devine formula uses a different base weight for men and women.
- Enter your height.
- Read the Devine reference weight and the healthy BMI-based weight range, and treat both as guides.
- If your height is under 5 ft, note the on-screen warning that the Devine formula is extrapolating below its design range, and lean on the BMI band instead.
Formula & method
Worked examples
A man who is 5 ft 10 in (70 inches, 1.778 m) tall.
- Inches over 5 ft = 70 - 60 = 10
- Devine = 50 + 2.3 x 10 = 50 + 23 = 73.0 kg
- BMI band = 18.5 x 1.778 squared to 24.9 x 1.778 squared
- = 18.5 x 3.161 to 24.9 x 3.161 = 58.5 to 78.7 kg
Result: Devine 73.0 kg; healthy range about 58.5 to 78.7 kg
A woman who is 5 ft 5 in (65 inches, 1.651 m) tall.
- Inches over 5 ft = 65 - 60 = 5
- Devine = 45.5 + 2.3 x 5 = 45.5 + 11.5 = 57.0 kg
- BMI band = 18.5 x 1.651 squared to 24.9 x 1.651 squared
- = 18.5 x 2.726 to 24.9 x 2.726 = 50.4 to 67.9 kg
Result: Devine 57.0 kg; healthy range about 50.4 to 67.9 kg
A woman who is 4 ft 11 in (59 inches, 1.499 m) tall, just under 5 ft.
- Inches over 5 ft = 59 - 60 = -1
- Devine = 45.5 + 2.3 x (-1) = 45.5 - 2.3 = 43.2 kg
- Because this is below 5 ft, the Devine formula is extrapolating outside its usual range
- BMI band = 18.5 x 1.499 squared to 24.9 x 1.499 squared = 41.6 to 55.9 kg
Result: Devine 43.2 kg (extrapolated, less reliable); healthy BMI range about 41.6 to 55.9 kg
Devine ideal weight and healthy BMI range by height (adults)
| Height | Devine (men) | Devine (women) | Healthy BMI range |
|---|---|---|---|
| 5 ft 0 in (152 cm) | 50.0 kg | 45.5 kg | 42.7 to 57.5 kg |
| 5 ft 4 in (163 cm) | 59.2 kg | 54.7 kg | 49.2 to 66.2 kg |
| 5 ft 8 in (173 cm) | 68.4 kg | 63.9 kg | 55.4 to 74.5 kg |
| 6 ft 0 in (183 cm) | 77.6 kg | 73.1 kg | 62.0 to 83.4 kg |
| 6 ft 4 in (193 cm) | 86.8 kg | 82.3 kg | 68.9 to 92.8 kg |
BMI categories (World Health Organization, adults)
| BMI | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 to 24.9 | Healthy weight |
| 25.0 to 29.9 | Overweight |
| 30.0 and above | Obesity |
Other published ideal body weight formulas, for comparison (this calculator uses Devine)
| Formula (year) | Men | Women |
|---|---|---|
| Devine (1974) | 50.0 kg + 2.3 kg per inch over 5 ft | 45.5 kg + 2.3 kg per inch over 5 ft |
| Robinson (1983) | 52.0 kg + 1.9 kg per inch over 5 ft | 49.0 kg + 1.7 kg per inch over 5 ft |
| Miller (1983) | 56.2 kg + 1.41 kg per inch over 5 ft | 53.1 kg + 1.36 kg per inch over 5 ft |
| Hamwi (1964) | 48.0 kg + 2.7 kg per inch over 5 ft | 45.5 kg + 2.2 kg per inch over 5 ft |
Common mistakes to avoid
- Treating the Devine number as a hard target. The Devine formula gives one reference figure that was designed for medication dosing, not diet goals. Health spans a range, so the BMI band is usually the more realistic guide.
- Applying it to athletes or very muscular people. Muscle is denser than fat, so a fit, muscular person can weigh above an "ideal" figure and still have low body fat. Neither the Devine formula nor BMI separates muscle from fat.
- Using it for children or during pregnancy. These formulas are built for non-pregnant adults. Healthy weight in children is judged against age-and-sex growth charts, and pregnancy weight should be guided by a clinician.
- Mixing height units. Entering centimetres in the imperial fields, or feet in the metric field, produces a wrong result. Pick one unit system and stay in it.
- Assuming every ideal weight formula gives the same answer. Devine, Robinson, Miller and Hamwi can differ by several kilograms for the same height and sex. Treat any single formula as one estimate among a few, not an exact fact.
- Confusing "ideal" with "goal" weight. A population formula cannot know your history, lifestyle or health conditions. A sustainable, realistic goal weight, set with a professional, may reasonably sit outside these ranges.
Glossary
- Ideal body weight (IBW)
- A reference weight estimated from height and sex, used as a guide and, in medicine, to help calculate some drug doses.
- Devine formula
- A 1974 equation that estimates ideal body weight from height: a base weight at 5 ft plus 2.3 kg per inch above 5 ft. Used by this calculator.
- BMI
- Body Mass Index: weight in kilograms divided by height in metres squared. A BMI of 18.5 to 24.9 is classed as a healthy weight.
- Healthy weight range
- The span of weights for your height that fall within a BMI of 18.5 to 24.9, rather than a single number.
- Robinson formula
- A 1983 ideal body weight equation: 52 kg + 1.9 kg per inch over 5 ft for men, 49 kg + 1.7 kg per inch over 5 ft for women.
- Miller formula
- A 1983 ideal body weight equation: 56.2 kg + 1.41 kg per inch over 5 ft for men, 53.1 kg + 1.36 kg per inch over 5 ft for women.
- Hamwi formula
- The earliest (1964) ideal body weight equation, developed for nutrition assessment: 48 kg + 2.7 kg per inch over 5 ft for men, 45.5 kg + 2.2 kg per inch over 5 ft for women.
- Adjusted body weight (ABW)
- A figure used mainly in medicine for patients well above their ideal weight, calculated as ideal weight plus 40 percent of the difference between actual and ideal weight. Used for some drug dosing, not personal goals.
Frequently asked questions
What is my ideal weight?
Your ideal weight is best seen as a range, not one number. This calculator shows the Devine-formula reference figure for your height and sex alongside the healthy weight range that matches a BMI of 18.5 to 24.9. A weight anywhere in that band is generally considered healthy.
How is ideal weight calculated?
The Devine formula starts at 50 kg for men or 45.5 kg for women at a height of 5 feet, then adds 2.3 kg for every inch above 5 feet. The healthy range comes from BMI: multiply 18.5 and 24.9 by your height in metres squared.
Is the Devine formula accurate?
It is a useful reference and is still used in clinical dosing, but it was not designed as a personal diet goal. It works best for adults of roughly average height and ignores muscle, frame size and body fat, so pair it with the BMI range and professional advice.
What is a healthy weight for my height?
A healthy weight is one that puts your BMI between 18.5 and 24.9. For example, a person 1.7 m (about 5 ft 7 in) tall has a healthy range of roughly 53 to 72 kg. Enter your height above to see your own band.
Does muscle affect ideal weight?
Yes. Muscle is denser than fat, so muscular people can weigh more than an "ideal" figure while still being lean and healthy. Because neither the Devine formula nor BMI separates muscle from fat, very fit people should read the results with that in mind.
What is the difference between ideal weight and BMI?
Ideal weight (the Devine figure here) is a single reference number for your height and sex. BMI is a formula, weight divided by height squared, that this calculator rearranges into a whole range of weights classed as healthy, rather than one point figure.
What formula do doctors and pharmacists use for ideal body weight?
Devine is the most widely used formula for medication dosing calculations, though Robinson, Miller and Hamwi are also published and used in some settings. For the same height they typically differ by only a few kilograms.
Does ideal weight change with age?
The Devine, Robinson, Miller and Hamwi formulas do not adjust for age at all. In reality, adults tend to lose muscle and gain fat as they get older, so the same reference number can reflect a different, less muscular body composition later in life.
What is adjusted body weight and when is it used?
Adjusted body weight adds 40 percent of the gap between actual body weight and ideal body weight back onto the ideal figure. Clinicians use it mainly to dose certain medications for patients well above their ideal weight, not as a personal weight-loss target.
Does this calculator store my data?
No. Everything runs in your browser with JavaScript. Your sex and height are never sent to a server or saved anywhere.
Sources
- Devine BJ, Gentamicin therapy (origin of the ideal body weight formula) , Drug Intelligence & Clinical Pharmacy (1974)
- The origin of the "ideal" body weight equations (Devine, Robinson, Miller, Hamwi compared) , Annals of Pharmacotherapy (2000)
- A healthy lifestyle, WHO recommendations (body mass index) , World Health Organization