Ideal Weight Calculator
Calculate your medically recommended ideal body weight range based on multiple clinical formulas and frame sizes.
Body Parameters
Small Frame
Under 16.5 cm (6.5")
Medium Frame
16.5 cm to 19.1 cm (6.5" - 7.5")
Large Frame
Over 19.1 cm (7.5")
Average Ideal Body Weight
69.8
kgHealthy BMI Weight Range
56.7 – 76.3 kg
(Based on standard WHO height-to-weight index bounds of 18.5 – 24.9)
Clinical Std (Devine)
70.5 kg
Empirical Target (Robinson)
68.9 kg
Active Frame Setting
medium Frame Adjustment
Standard formula outputs are evaluated at 100% (no multiplier adjustments applied).
Comparative Formula Output
Scientific Context & Guidelines
Limitations of IBW Equations
Ideal Body Weight (IBW) equations are based solely on height and biological sex. They do not distinguish between body fat and skeletal muscle tissue. Therefore, heavily muscled individuals, strength athletes, or bodybuilders will often register as "overweight" relative to IBW targets, despite having extremely low body fat.
Frame Adjustment Rationale
By selecting a medium frame size, calculations adjust standard outputs by ±10%. Skeletal structure accounts for a substantial percentage of total weight. Accounting for frame size prevents unrealistic targets for large-framed individuals and ensures healthy goals for small-framed individuals.
WHO Classification Milestones
The table below displays your specific weight brackets for each clinical category based on a height of 175 cm (or 6ft 9in).
| BMI Category | BMI Range | Weight Bracket |
|---|---|---|
Underweight | Below 18.5 | Under 56.7 kg |
Normal Weight | 18.5 – 24.9 | 56.7 – 76.3 kg |
Overweight | 25.0 – 29.9 | 76.6 – 91.6 kg |
Obese (Class I) | 30.0 – 34.9 | 91.9 – 106.9 kg |
Severe Obesity | 35.0 and above | Over 107.2 kg |
How to Use This Ideal Weight Calculator
To get the most accurate baseline for your ideal weight range, you need to provide more than just your height and gender. By factoring in your frame size and age (used specifically in the Creff formula), we can provide a much tighter, more personalized estimate. Here is how to use the tool properly:
Basic Metrics
Select your biological sex and preferred measurement system (Metric or US). Enter your exact height in centimeters or feet and inches.
Age Factor
While most formulas ignore age, the Creff formula uses it to adjust your target. Enter your current age to see this age-adjusted estimate.
Determine Frame Size
Use a flexible measuring tape to measure your wrist circumference just above the bone. Use the table below the calculator to see if you have a small, medium, or large frame.
Review Your Delta
Optionally, enter your current weight to see exactly how far you are from the average ideal target.
Why Frame Size Matters: The concept of body frame sizing originates from the 1959 Metropolitan Life Insurance tables. Adjusting for frame size shifts your final target weight up or down by 10%. Without it, a broad-shouldered individual and a very narrow-framed individual of the same height are given the exact same target, which is biologically inaccurate.
What This Calculator Actually Tells You (And What It Doesn't)
Let's be direct: these formulas give you a clinical reference range, not an absolute personal fitness target. When you look at your results, you'll likely notice that the six different formulas do not agree with each other. In fact, they can disagree by up to 14% to 19% for the exact same person.
For example, take a 5'6" female with a medium frame. The Miller formula might suggest her ideal weight is 121.3 lbs (55.0 kg), while the Hamwi formula might suggest 130.2 lbs (59.1 kg). That is nearly a 10 lb spread. Why the difference? Because each formula was designed by a different physician, in a different decade, for a slightly different purpose.
This is exactly why our calculator shows all six formulas and provides the average. Averaging the formulas smooths out the mathematical biases of any single equation.
We also show the standard Body Mass Index (BMI) range band (18.5 to 24.9). While BMI is a flawed metric, we include it because it remains the standard screening tool used by primary care physicians and insurance companies today. Understanding where your "ideal" formulas land within the broad BMI band gives you complete context for your next doctor's visit.
The Honest Origin Story (What Most Sites Won't Tell You)
Most people assume that "ideal body weight" formulas are the result of advanced, modern exercise science designed to tell you what a perfectly healthy human body looks like. They aren't.
From Insurance Tables to IV Bags
The foundation for most of these equations dates back to 1959, when the Metropolitan Life Insurance Company published height-weight tables. These tables weren't built by doctors optimizing human health; they were built by actuaries optimizing insurance premiums based on mortality data from a largely white, middle-class American demographic. It was not a diverse or representative dataset.
Fast forward to 1974. Dr. B.J. Devine published what is now the most famous formula in the world: the Devine Formula. However, Dr. Devine did not create it to tell people how much they should weigh to look good or be fit. He created it to calculate the exact dosage of the antibiotic gentamicin.
Pharmacology, Not Fitness
Gentamicin is a drug that distributes into lean tissue, but not fat. If a doctor gave a highly obese patient a dose based on their total scale weight, it could be toxic. Dr. Devine needed a mathematical shortcut to estimate "lean mass" so doctors wouldn't overdose their patients. His formula was a quick clinical hack that worked well enough for pharmacology.
Later researchers, like Robinson and Miller in 1983, realized Devine's math was a bit rough. They ran linear regressions against the old 1959 insurance tables to create "better" versions of Devine's equation.
The Implication: When you plug your data into an ideal weight calculator, you are getting a number rooted in 1950s life insurance actuarial tables and a 1970s drug dosing shortcut. It is a helpful reference, but it should absolutely not dictate your self-worth.
Formula Comparison: A Real-World Example
To see how wildly these formulas can differ, let's look at a consistent example: a 30-year-old female who is 5'6" (167.6 cm) with a medium body frame. Here is exactly what the top six medical formulas tell her she should weigh.
| Formula | Original Purpose | 5'6" Female Target |
|---|---|---|
| Hamwi | Clinical quick-reference | ~59.1 kg (130.2 lbs) |
| Devine | Gentamicin drug dosing | ~58.1 kg (128.1 lbs) |
| Robinson | Population regression | ~56.8 kg (125.2 lbs) |
| Miller | Athletic lean baseline | ~55.0 kg (121.3 lbs) |
| Lorentz | European clinical standard | ~58.5 kg (129.0 lbs) |
| Creff | Age-adjusted French formula | ~57.2 kg (126.1 lbs) |
*Notice the nearly 9 lb gap between the Miller formula and the Hamwi formula. This proves that the "right" answer isn't a single magical number—it is a spectrum.
Three Groups Who Should Ignore These Numbers
Because these formulas were built on averages for the general population, they fail spectacularly when applied to specific groups. If you fall into one of these three categories, you need to interpret your results differently.
Scenario A: Athletes
High Muscle Mass
The Problem: Muscle Density
Muscle tissue is roughly 18% denser than fat (1.06 g/cm³ compared to 0.9 g/cm³). A highly trained athlete at 5'10" and 190 lbs with 10% body fat is in peak physical condition, yet the Devine formula will confidently categorize them as 20 lbs overweight. If you strength train regularly, your ideal scale weight will always be significantly higher than these formulas predict. Pair this calculator with a Body Fat % measurement instead.
Scenario B: Over 60
The Aging Paradox
The Problem: Protective Fat Reserves
As we age, being slightly heavier is actually healthier. Multiple massive cohort studies—including a 2016 JAMA study of over 310,000 adults—demonstrate the "obesity paradox" in older populations. For adults over 65, a BMI between 25 and 27.5 (which these formulas consider "overweight") is associated with lower all-cause mortality. Slight fat reserves protect against frailty, bone fractures, and severe illness recovery.
Scenario C: Under 5'0"
Short Stature Mathematics
The Problem: Formula Failure
The Devine, Robinson, and Miller formulas explicitly use a base calculation starting at 60 inches (5 feet). If you are 4'10", the formula attempts to calculate negative inches over 5 feet, which breaks the math. While our calculator corrects for this by clamping values, if you are under 5 feet tall, you should heavily weight the Lorentz and Creff formulas, which scale linearly with total height rather than using an arbitrary 5-foot baseline.
Beyond the Scale: 3 Metrics That Tell You More
If ideal weight formulas are flawed, what should you measure instead? Current medical research points to three alternative metrics that are vastly superior at predicting actual metabolic health.
1. Waist-to-Height Ratio (WHtR)
A massive 2016 systematic review (300,000+ participants) found that dividing your waist by your height is a better predictor of heart disease and diabetes than BMI. The Golden Rule: Keep your waist circumference to less than half of your total height.
2. Body Fat Percentage
Formulas assume average body composition. A 5'10" man at 185 lbs and 10% body fat carries 167 lbs of lean muscle. That exact same man at 30% body fat carries only 130 lbs of lean muscle. The scale weight is identical; the health reality is entirely different.
3. Raw Waist Circumference
This is the metric most primary care doctors actually care about. According to NIH guidelines, your metabolic risk skyrockets if your waist exceeds 40 inches (102 cm) for men, or 35 inches (88 cm) for women. Visceral belly fat is highly inflammatory.
The "Happy Weight" Problem Nobody Talks About
There is a quiet psychological crisis in weight management: people are chasing clinical, drug-dosing targets while their body is desperately trying to find its natural equilibrium.
NIH-funded research shows that the average person's "goal weight" sits about 11 lbs below their "happy weight"—the weight where they actually feel comfortable, can sustain their diet without misery, and have energy to live their life. Even worse, their mathematically "ideal weight" is often another 10 lbs below that.
The "happy weight" concept isn't a modern excuse for laziness; it is your body's biological set-point theory in practice (Keesey & Powley, 1986). Your body tightly regulates its fat stores. If you force your weight down to an arbitrary Devine formula number that your genetics don't support, your body will fight you with relentless hunger hormones and metabolic slowdown.
The Practical Takeaway
If you are within 10% to 15% of your ideal weight range, you consistently pass your annual lab panels (blood pressure, cholesterol, HbA1c), and you have the physical capability to do the things you love—that is the definition of a healthy weight. The number on the calculator is a starting point for a conversation with your doctor, not a verdict on your health.
Frequently Asked Questions
There is no single "most accurate" formula, as they can differ by up to 14-19% (or around 10-15 lbs) for the exact same person. Devine is the most commonly used in clinical settings for calculating drug dosages, while Robinson and Miller were designed to better fit the general population. We recommend looking at the average of all the formulas and treating it as a broad target range rather than a precise goal.
The formulas you see in most ideal weight calculators were not designed for fitness or health goals. The Devine formula (1974) was created to calculate the correct dosage of the antibiotic gentamicin. The Hamwi formula (1964) was a simple bedside rule of thumb for nurses. Later formulas (Robinson and Miller in 1983) were regressions based on 1959 life insurance actuarial tables used to set mortality premiums. The fact that they became fitness targets is a quirk of medical history.
Yes, significantly. Frame size adjustments (typically derived from wrist circumference) can shift your final target weight by 10%. For a 150 lb average target, having a small or large frame can move your result down or up by 5 to 7 kg (11 to 15 lbs). This accounts for the natural variations in bone density and joint width that standard height-weight formulas otherwise ignore.
If you have a high amount of muscle mass, you should ignore ideal weight formulas entirely. Muscle tissue is roughly 18% denser than fat. A trained athlete with 10% body fat will almost always weigh more than these formulas suggest and may even be classified as "overweight." For athletes, tracking body fat percentage and performance metrics is far more accurate than scale weight.
Standard ideal weight formulas do not adjust for age, which is a major limitation. Large-scale research (including a massive JAMA study of over 300,000 adults) found that for people over 65, a Body Mass Index (BMI) of 25 to 27.5—which is technically classified as "overweight"—is actually associated with lower all-cause mortality. Slightly higher weight in older adults provides protective reserves against illness and frailty.
The mathematics of the Devine formula are based on a baseline height of 5 feet (60 inches). For men, it starts at 50 kg for the first 5 feet, then adds 2.3 kg for every inch over 5 feet. If you are under 5 feet, the formula actually subtracts weight, leading to dangerously low or even negative results. For shorter individuals, the Lorentz or Creff formulas offer a more realistic baseline.
They overlap, but they are not the same. BMI gives you a very broad healthy range (from 18.5 to 24.9). Ideal weight formulas attempt to pinpoint a single specific number within that range based on your exact height and frame. However, both metrics share the same critical flaw: neither can tell the difference between fat and muscle.
Your "ideal weight" is a clinical, mathematical estimate based on your height. Your "happy weight" is the weight your body naturally settles at when you are eating sustainably, exercising regularly, and living your life without extreme restriction. NIH research shows most people's happy weight is 10 to 15 pounds above their clinical ideal weight.
You do not need to reach your "ideal weight" to see massive health benefits. According to the CDC, losing just 5% to 10% of your total body weight is enough to produce clinically meaningful improvements in blood pressure, cholesterol, and insulin sensitivity, even if you are still classified as overweight afterward.
According to the National Institutes of Health (NIH), your metabolic risk increases significantly if your waist circumference is above 40 inches (102 cm) for men or above 35 inches (88 cm) for women. This is true regardless of what the scale says, because visceral belly fat is highly active and drives inflammation and insulin resistance.
Complete Your Health Profile
Scale weight is just one small data point. Use our other professional-grade tools to build a more accurate picture of your metabolic health and fitness.