🏃 Health & Fitness

Ideal Body Weight Calculator

Compare four established medical formulas side by side, adjusted for your frame size — plus your healthy weight range by BMI.

Advertisement
📏
Ideal Body Weight Calculator

“Ideal weight” formulas are clinical estimates, often used for medication dosing — they’re reference points, not personal targets. This is informational only, not medical advice.

Units
Biological Sex
Body Frame Size
Estimate by wrapping your thumb and middle finger around your opposite wrist: overlap = small, touch = medium, gap = large
Please enter your height to continue.
Average Ideal Body Weight
0
Devine
0
1974 · dosing standard
Robinson
0
1983
Miller
0
1983
Hamwi
0
1964
Healthy Weight Range (BMI 18.5–24.9)
0
A broader, modern reference based on your height
Important: These formulas were originally developed for clinical purposes like medication dosing, and don’t account for muscle mass, age, or body composition. A muscular athlete may register “over” their ideal weight while being perfectly healthy. Treat these as reference points and talk to a doctor about what’s right for you.
Advertisement

What Is “Ideal Body Weight”?

Ideal body weight (IBW) formulas estimate a reference weight based primarily on height and sex. They originated in clinical medicine — mainly for calculating medication dosages — rather than as personal fitness goals. That’s an important distinction: these are population-level reference points, not a verdict on any individual’s health.

The Four Formulas Compared

Devine (1974): 50.0 kg + 2.3 kg per inch over 5 ft (male)
Robinson (1983): 52.0 kg + 1.9 kg per inch over 5 ft (male)
Miller (1983): 56.2 kg + 1.41 kg per inch over 5 ft (male)
Hamwi (1964): 48.0 kg + 2.7 kg per inch over 5 ft (male)

Each uses a different base weight and per-inch increment, which is why they produce slightly different numbers. This calculator runs all four and averages them, then adjusts for your selected frame size.

How to Use This Calculator

Enter your height and biological sex, then estimate your frame size using the wrist test described in the form. The result shows all four formula outputs side by side, their average, and — separately — the healthy weight range based on the modern BMI standard, which many clinicians now consider more practical than single-number IBW formulas.

Why Frame Size Matters

Two people of identical height can have meaningfully different healthy weights based on bone structure. A common adjustment subtracts about 10% for a small frame and adds about 10% for a large frame. The wrist-circumference method in the form is a quick, rough way to estimate which category you fall into.

💡 The healthy BMI range shown is usually wider and more forgiving than the single IBW number — for most people it’s a more realistic reference than any one formula’s exact figure.

The Big Limitation: Body Composition

None of these formulas can tell the difference between muscle and fat. A lean, muscular athlete often weighs “more” than their IBW while being extremely healthy, and someone within their “ideal” weight can still have low muscle mass. This is the single biggest reason IBW should never be treated as a strict target.

IBW vs. BMI vs. Body Fat

  • IBW formulas: a single reference number, historically used for clinical dosing
  • BMI: a height-to-weight ratio giving a healthy range, simple but also blind to muscle vs. fat
  • Body fat percentage: the most informative of the three for body composition, but harder to measure accurately

Important Health Note

This calculator is for general informational purposes only and is not medical advice, a diagnosis, or a weight-loss prescription. Healthy weight varies enormously between individuals. If you have concerns about your weight, a health condition, or any history of disordered eating, please speak with your doctor or a registered dietitian rather than relying on a formula.

Where This Fits

Compare this against our BMI calculator for the range-based view, our body fat calculator for composition, and our macronutrient calculator if you’re planning your nutrition around a goal.

Frequently Asked Questions

Which ideal body weight formula is most accurate?
None is definitively “most accurate” — they were built for different purposes. The Devine formula is the most widely used in clinical settings for medication dosing. Averaging all four gives a reasonable general reference.
Why do the four formulas give different numbers?
Each uses a different base weight and per-inch increment, derived from different datasets and eras. The spread between them shows how much “ideal weight” is an approximation rather than an exact figure.
Should I use IBW as my weight goal?
Not strictly — these formulas ignore muscle mass, age, and body composition. The healthy BMI range is usually a more practical reference, and a doctor can give personalized guidance.
How do I measure my frame size?
Wrap your thumb and middle finger around the opposite wrist. If they overlap, you likely have a small frame; if they just touch, medium; if there’s a gap, large.
Why might an athlete weigh more than their ideal weight?
Muscle is denser than fat, so a muscular person can exceed their IBW while having low body fat and excellent health. IBW formulas can’t distinguish muscle from fat.
Does ideal body weight change with age?
These formulas don’t adjust for age, though body composition naturally shifts over time. This is one of their known limitations as a personal reference.
Is the BMI range better than an IBW formula?
For most people, the BMI range is more practical because it gives a healthy span rather than a single number — but it shares the same blind spot around muscle versus fat.
Is this calculator suitable for children or teens?
No — these adult formulas don’t apply to growing children and teens, who should be assessed using age-and-sex-specific growth charts by a pediatrician.
Advertisement
Advertisement
Related Tools
⚖️BMI Calculator 📊Body Fat Calculator 🥗Macronutrient Calculator 🔥TDEE Calculator 💧Water Intake Calculator ⚡BMR Calculator
Scroll to Top