Ideal Body Weight Calculator
Discover what your optimal weight should be based on medical standards. We compare 4 different formulas (Devine, Robinson, Miller, and Hamwi) to give you a comprehensive range.
Multiple Formulas
Compare 4 methods
Height Based
Optimized for you
Gender Specific
Male vs Female logic
Healthy Range
Min/Max targets
What is Ideal Body Weight?
IBW is a medical calculation used to estimate the healthy weight for a person of a given height. It was originally designed to calculate drug dosages but is now widely used for health goals.
More Than One Answer
There is no single "perfect" weight. Different researchers have developed different formulas over the decades. This calculator provides the results from the four most respected equations so you can see the average consensus.
Devine Formula (1974)
The most widely used standard in medicine.
Robinson Formula (1983)
Refined the Devine formula for slightly different body structures.
Miller Formula (1983)
Often provides a slightly lower estimate.
Hamwi Formula (1964)
The original "Rule of Thumb" for body weight.
Consensus View
We average all major formulas to give you a reliable "Target Weight" rather than just one isolated number.
BMI Comparison
We cross-reference your result with the Healthy BMI Range (18.5 - 24.9) to ensure it's medically sound.
Simple Inputs
You don't need tape measures or calipers. Just your height and gender are enough for an accurate calculation.
Why Choose Our IBW Tool?
Comprehensive Analysis
Most calculators use only one formula. We show you four, providing a more complete picture.
Instant & Private
Zero loading time, no sign-ups, and your data stays in your browser.
Mobile Optimized
Designed to be easy to read and use on any device screen size.
Calculate Your Ideal Weight
Enter your height and gender below.
How to Use the IBW Calculator
Finding your ideal weight is just a few clicks away.
Select Your Parameters
Start by choosing your gender. The formulas are different for men and women because men typically have heavier bone density and muscle mass. Then, pick your preferred unit (Metric or Imperial).
Input Your Height
Enter your height accurately. Ideal Body Weight is calculated based on how tall you are, specifically measuring how much you exceed 5 feet (152 cm).
Review the Results
Click calculate to see the results from four different medical formulas. Use the "Average" result as your primary target, but understand that falling anywhere within the range of the four formulas is generally considered healthy.
Understanding the Calculations
How each formula determines your ideal weight. (Base: Height over 5 feet)
Devine Formula (1974)
Originally intended for dosing medications like gentamicin, it became the standard.
Women: 45.5kg + 2.3kg per inch over 5ft
Robinson Formula (1983)
Modification of Devine to provide more accurate results for modern populations.
Women: 49kg + 1.7kg per inch over 5ft
Miller Formula (1983)
Often results in a lower weight estimate.
Women: 53.1kg + 1.36kg per inch over 5ft
Hamwi Formula (1964)
Known as the "Rule of Thumb", very easy to remember.
Women: 45.5kg + 2.2kg per inch over 5ft
Applications of This Tool
Who should use the IBW calculator?
Realistic Goal Setting
If you are starting a weight loss journey, picking an arbitrary number can be discouraging. IBW gives you a scientifically backed target to aim for.
Medical Dosage
Doctors often use IBW to calculate dosages for medications. Using actual body weight for obese patients can lead to overdose, so IBW is safer.
Calculation Example
Let's break down how the numbers work for a standard scenario.
Case Study: Mark
Male, 5 ft 10 in (178 cm)
Most formulas use a base weight for 5 feet of height, and then add a specific amount for every inch over 5 feet.
= 50 + 23
= 73 kg (approx 161 lbs)
= 52 + 19
= 71 kg (approx 156 lbs)
Why it matters
Notice how the formulas give slightly different results? Mark isn't "unhealthy" if he weighs 71kg or 73kg.
These formulas provide a baseline reference. If Mark is a bodybuilder with significant muscle mass, he might weigh 85kg and still be healthy, despite being "overweight" according to this specific calculation.
Key Takeaway: Use the calculator to find a "center point" for your health goals, but allow for a +/- 10% variation based on your body frame size and muscle mass.
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Frequently Asked Questions
Is IBW realistic?
IBW is a clinical estimate. It does not account for muscle mass or bone density. An athlete might weigh more than their IBW but be perfectly healthy. It should be used as a general guideline, not a strict rule.
Why are there different formulas?
Researchers created formulas based on population data available at the time. As average heights and weights shifted over decades, new formulas (like Robinson and Miller) were created to refine the original Devine formula.
What if I am under 5 feet tall?
These formulas are designed for adults 5 feet (152cm) or taller. For those shorter, the formulas simply subtract weight for every inch under 5ft, but accuracy decreases.
How does this differ from BMI?
BMI gives a *range* (e.g., 18.5-25) based on height. IBW gives a *specific target number* (e.g., 70kg). IBW is often used to find the "middle" of the healthy BMI range.