What is the most accurate ideal weight formula?

No single formula is definitively "most accurate" — Devine, Hamwi, Robinson, and Miller are all used clinically and can differ by 5–10 lb for the same height. Devine is the most widely used today, particularly in medical dosing calculations, but all are population averages rather than individualized measurements.

Is ideal body weight the same as healthy weight?

Not exactly. Ideal body weight formulas produce a single reference number based only on height and sex. Healthy weight is a broader concept that also considers body composition, muscle mass, waist circumference, and overall health markers — which is why doctors typically treat ideal weight as a starting reference, not a target.

Why do men and women have different ideal weight formulas?

The Devine formula's baseline constants (50 kg for men, 45.5 kg for women) reflect average population differences in lean body mass and frame size between sexes at the same height, based on the clinical data used to derive the formula in 1974.

Does ideal weight account for muscle mass?

No. Ideal weight formulas use only height and sex, so they don't distinguish muscle from fat. A muscular athlete will typically weigh more than the formula's estimate without being overweight — body fat percentage is a better measure for that distinction.

What is the Devine formula used for medically?

The Devine formula was originally created to estimate ideal body weight for calculating medication dosages, particularly for drugs where dosing by actual body weight could be inaccurate or unsafe in overweight or underweight patients, such as certain anesthetics and antibiotics.

How much should I weigh for my height?

As a reference point, the Devine formula gives roughly 106 lb for a 5-foot woman plus about 5 lb per inch above that, and 110 lb for a 5-foot man plus about 5 lb per inch above that. But healthy weight ranges are broad — BMI charts, which allow roughly a 30–40 lb range per height, are generally considered more clinically useful than a single ideal weight number.

Ideal Weight

Health & Fitness

Calculate your ideal weight range

Height (cm)

Gender

Frame Size

An ideal weight calculator estimates a reference healthy body weight based on your height and sex, using formulas originally developed for medical dosing calculations. Our calculator uses the Devine formula, the most widely used version in clinical settings today: for men, ideal body weight (kg) = 50 + 2.3 × (height in inches over 60); for women, 45.5 + 2.3 × (height in inches over 60).

The Devine formula was created in 1974 to help clinicians calculate medication dosages for patients whose actual weight might be misleading (due to obesity, edema, or amputation). It was never designed as a fitness or aesthetic target, but it has become a popular reference point because it's simple, well-documented, and reasonably consistent with population health data.

Importantly, this is one of several competing formulas — Hamwi, Robinson, and Miller are other commonly used equations, and each produces a slightly different number for the same height. None of them account for muscle mass, bone density, or body frame, so treat the result as a general reference range rather than a strict target you must hit.

Why Ideal Weight Matters

Ideal weight calculations matter most in clinical contexts: doctors and pharmacists use them to dose medications (especially anesthesia and certain antibiotics) more safely than using actual body weight alone, particularly for patients who are significantly overweight or underweight.

For general users, an ideal weight range provides a rough benchmark when setting weight loss or weight gain goals, especially when combined with other measures like BMI and body fat percentage. Used alone, however, ideal weight formulas can be misleading — they assume an "average" body composition and don't distinguish a muscular, athletic person from someone with the same weight but higher body fat.

Because the various formulas (Devine, Hamwi, Robinson, Miller) were each derived from different population data and can disagree by 5–10 pounds for the same height, no single number should be treated as a precise medical target. Most clinicians now recommend viewing ideal weight as a range, and pairing it with BMI, waist circumference, or body fat percentage for a more complete picture of health.

The Ideal Weight Formula, Explained

Men: IBW (kg) = 50 + 2.3 × (height in inches − 60). Women: IBW (kg) = 45.5 + 2.3 × (height in inches − 60)

Where: height in inches = your height converted to inches (60 inches = 5 feet, the formula's baseline), IBW = ideal body weight in kilograms, which the calculator also converts to pounds (1 kg = 2.20462 lb).

The formula assumes a baseline weight at 5 feet tall (60 inches) and adds 2.3 kg for every inch of height above that baseline. Men get a higher baseline (50 kg vs. 45.5 kg) reflecting average differences in frame size and lean mass between sexes at the same height.

For heights under 5 feet, the formula is typically not extrapolated backward, since it wasn't validated for that range — most calculators, including this one, note that the formula is most reliable for adult heights between about 5'0" and 6'6".

How to Use the Ideal Weight: Step by Step

Select your sex
Choose male or female — the calculator uses a different baseline constant for each (50 kg for men, 45.5 kg for women).
Enter your height
Input your height in feet/inches or centimeters. The calculator converts to total inches internally for the formula.
Review your ideal weight range
The result shows your Devine formula estimate in both kg and lb, along with a healthy range accounting for formula variation.
Compare to other formulas (optional)
If available, toggle to see Hamwi, Robinson, or Miller formula results side by side — they typically differ by 5–10 lb for the same height.
Use alongside BMI and body fat
Cross-check your result against the BMI Calculator and Body Fat Calculator rather than treating the ideal weight number as a strict target.

Ideal Weight Examples: Real-World Scenarios

Man, 5'10"

James is 5'10" (70 inches) tall and wants a reference healthy weight range.

Height:70 in (5'10")

Sex:Male

Calculation

IBW = 50 + 2.3 × (70 − 60) = 50 + 2.3 × 10 = 50 + 23 = 73.0 kg

Result

Ideal body weight: 73.0 kg (160.9 lb). A commonly cited healthy range around this figure is roughly 154–168 lb, accounting for formula variation and frame size.

Woman, 5'5"

Elena is 5'5" (65 inches) tall and wants to know her Devine formula reference weight.

Height:65 in (5'5")

Sex:Female

Calculation

IBW = 45.5 + 2.3 × (65 − 60) = 45.5 + 2.3 × 5 = 45.5 + 11.5 = 57.0 kg

Result

Ideal body weight: 57.0 kg (125.7 lb). A reasonable healthy range around this figure is approximately 119–132 lb.

Tall Man, 6'2"

Marcus is 6'2" (74 inches) tall, above-average height, and wants his reference weight.

Height:74 in (6'2")

Sex:Male

Calculation

IBW = 50 + 2.3 × (74 − 60) = 50 + 2.3 × 14 = 50 + 32.2 = 82.2 kg

Result

Ideal body weight: 82.2 kg (181.2 lb). Because the formula scales linearly per inch, taller individuals see a proportionally larger reference weight.

Common Mistakes to Avoid

Treating the result as an exact target — the Devine formula was designed for medication dosing, not as a personal fitness goal, and has a built-in margin of several pounds depending on frame and muscle mass.
Ignoring body frame size — a person with a large bone structure or high muscle mass will naturally weigh more than the formula suggests without carrying excess fat.
Comparing results across different formulas without noting they use different baselines — Devine, Hamwi, and Robinson formulas can disagree by 5–10 lb for the same height, so mixing them up produces confusing conclusions.
Applying the adult formula to growing children or teenagers — it is validated only for adults and will not produce meaningful results for anyone still growing.

Tips & Tricks

Use the ideal weight result as one data point alongside BMI and body fat percentage rather than a standalone goal.
If you're notably more muscular than average, expect your healthy weight to sit above the formula's estimate — that's normal and not a sign of poor health.
For clinical purposes (like medication dosing), always defer to your doctor or pharmacist's calculation rather than a self-service calculator.

The Devine formula gives a quick, standardized reference point for healthy body weight, but it's a starting point, not a verdict — actual healthy weight varies with muscle mass, frame size, and overall body composition. For a fuller picture, pair this calculator with the BMI Calculator to check your weight-to-height ratio and the Body Fat Percentage Calculator to see how much of your weight is lean mass versus fat.

Ideal Weight — Frequently Asked Questions

Related Calculators

BMI Calculator

check your weight-to-height ratio

Body Fat Percentage Calculator

see how much of your weight is lean mass

BMR Calculator

find your resting calorie burn

Calorie Calculator

plan a calorie target to reach a healthy weight

Macro Calculator

build a diet plan around your target weight

Authoritative References

NIH — Assessing Your Weight

nih.gov — National Institutes of Health guidance on healthy weight assessment

CDC — Healthy Weight, Nutrition, and Physical Activity

cdc.gov — Government reference on defining and reaching a healthy weight

World Health Organization — Body Mass Index and Weight

who.int — International health authority guidance on healthy weight standards

External links open in a new tab. OmniCalc.us is not affiliated with these organisations.

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