Ideal Weight Calculator
Calculate your ideal body weight using 4 scientific formulas: Robinson, Miller, Devine, and Hamwi. Compare results and find your healthy weight range.
Enter your height and sex to see ideal body weight estimates from five formulas (Robinson, Miller, Devine, Hamwi, Peterson). These are historical reference ranges, not personal targets.
What Does "Ideal Weight" Actually Mean?
There's no single "perfect" weight for any given height. But there is a range, backed by decades of mortality data and population studies, where your risk of chronic disease, joint problems, and metabolic issues is lowest. That's what ideal weight formulas try to pin down.
Think of it like a target zone on a dartboard. You don't need to hit the bullseye. Landing anywhere in the inner ring is great. The formulas above give you that inner ring, a healthy weight range for your height and sex that's associated with the best health outcomes in large population studies.
The important word is "associated." These formulas don't account for muscle mass, bone density, ethnic background, or individual body composition. A muscular person might be 15 kg above their "ideal weight" and be in excellent health. That's why this calculator shows results from four different formulas, to give you a range, not a single magic number.
The Four Formulas: Where They Come From
Each formula was developed in a different era, using different data. Understanding their origins helps you interpret the results:
Devine Formula (1974)
Men: 50 kg + 2.3 kg per inch over 5 feet | Women: 45.5 kg + 2.3 kg per inch over 5 feet
Originally created by Dr. B.J. Devine for drug dosing calculations, not as a health target. It was designed to estimate lean body mass for calculating medication dosages (like aminoglycosides). Despite this, it became the most widely used ideal weight formula in clinical settings. It tends to give the lowest estimates, especially for taller people.
Robinson Formula (1983)
Men: 52 kg + 1.9 kg per inch over 5 feet | Women: 49 kg + 1.7 kg per inch over 5 feet
Developed using actuarial mortality data, essentially, the weights at which people in large insurance databases lived the longest. Robinson refined the Devine formula with better data and is often considered the most balanced formula for general use. It gives slightly higher values than Devine for shorter people and lower values for taller people.
Miller Formula (1983)
Men: 56.2 kg + 1.41 kg per inch over 5 feet | Women: 53.1 kg + 1.36 kg per inch over 5 feet
Also based on actuarial data, but Miller's formula accounts more for frame size variation. It gives the highest baseline weight (56.2 kg for men at 5'0") but increases the slowest per inch of height. This makes it the most generous for shorter individuals and the most conservative for very tall people.
Hamwi Formula (1964)
Men: 48 kg + 2.7 kg per inch over 5 feet | Women: 45.5 kg + 2.2 kg per inch over 5 feet
The oldest formula, created as a simple rule of thumb. It adds the most weight per inch of height, making it the most generous for tall people and potentially unrealistic for shorter individuals. It's the least evidence-based of the four but remains popular due to its simplicity.
Which should you trust? The average of all four is usually the most sensible starting point. But pay attention to the full range, if all four formulas put you between 65 and 72 kg, that entire range is reasonable. Don't fixate on a single number.
Ideal Weight by Height (Average of 4 Formulas)
This reference table shows the average ideal weight across all four formulas for each height. Use it as a quick benchmark.
| Height | Men (kg) | Men (lbs) | Women (kg) | Women (lbs) |
|---|---|---|---|---|
| 5'0" / 152 cm | 51.6 | 114 | 48.3 | 106 |
| 5'3" / 160 cm | 57.8 | 127 | 53.3 | 117 |
| 5'6" / 168 cm | 64.1 | 141 | 58.3 | 129 |
| 5'9" / 175 cm | 70.3 | 155 | 63.4 | 140 |
| 6'0" / 183 cm | 76.5 | 169 | 68.4 | 151 |
| 6'3" / 191 cm | 82.8 | 182 | 73.4 | 162 |
What this means for you: These numbers assume average body composition. If you strength train regularly, you'll likely be 5 to 15 kg above these values and that's perfectly healthy. Use this table alongside your BMI and body fat percentage for a fuller picture.
Why Do the Formulas Give Different Numbers?
The four formulas can differ by as much as 5 to 8 kg for the same person. That's not a flaw, it reflects the genuine uncertainty in defining "ideal weight" from height alone.
Each formula was built from different populations, in different decades, using different statistical methods. Devine's data came from pharmaceutical dosing studies. Robinson and Miller used life insurance mortality tables. Hamwi used a simple linear model. None of them had access to body composition data, they only knew height, weight, and whether someone died prematurely.
The disagreement is actually useful. Instead of trusting any single formula, look at the range. If Devine says 68 kg and Hamwi says 75 kg, your reasonable target is somewhere in that 68 to 75 kg window. The calculator shows an average and the individual formula results so you can see exactly how wide the range is for your height.
What Ideal Weight Can't Tell You
These formulas have real limitations. Being aware of them prevents you from setting unrealistic or unhealthy targets:
No Body Composition
A 6-foot man at 90 kg with 12% body fat is muscular and healthy. The same man at 90 kg with 30% body fat is overweight. Both are "above ideal weight" by every formula. The number on the scale doesn't distinguish muscle from fat, your body fat percentage does.
No Ethnic Variation
These formulas were developed primarily from Caucasian populations. Research shows that healthy weight ranges vary by ethnicity, South Asian and East Asian populations face higher metabolic risk at lower BMIs, while Pacific Islander populations may have healthier outcomes at higher weights.
No Frame Size
Someone with a large skeletal frame naturally weighs more than a small-framed person of the same height. Only the Miller formula attempts to account for this. A rough check: wrap your thumb and middle finger around your wrist. If they overlap, you're small-framed. If they touch, medium. If they don't meet, large.
No Age Factor
These formulas give the same "ideal weight" for a 25-year-old and a 65-year-old. In reality, slightly higher body weight in older adults (BMI 25 to 27) is associated with lower mortality, the so-called "obesity paradox." Being a bit above ideal weight after 65 may actually be protective.
Bottom line: Treat ideal weight as a useful reference point, not a goal you must hit. Your actual health is better measured by body composition, blood markers, fitness level, and how you feel, not by matching a number from a formula developed 50 years ago.
Ideal Weight vs BMI: How Do They Compare?
The calculator also shows your healthy BMI range (18.5 to 24.9) converted to a weight range. This often gives a wider window than the formula-based ideal weight, which is useful context.
| Method | What It Shows | Range Width | Best Used For |
|---|---|---|---|
| Ideal Weight Formulas | A single "ideal" number per formula | Narrow (5 to 8 kg spread) | Setting a specific target weight |
| BMI Range (18.5 to 24.9) | The full "healthy weight" band | Wide (15 to 25 kg spread) | Understanding the full healthy zone |
What this means for you: If the formulas say your ideal weight is 70 kg but your BMI-based healthy range goes up to 82 kg, you're fine anywhere in that window. The BMI range is your safety net; the formula average is your centre target. Being anywhere in the healthy BMI range with a reasonable body fat percentage means you're in good shape. Use our BMI Calculator to check where you currently fall.
How to Set a Realistic Weight Goal
Knowing your ideal weight range is step one. Turning it into an actionable plan is step two. Here's a practical framework:
- Check where you are now: Calculate your BMI and body fat percentage. If both are in the healthy range, you're already there, regardless of what the ideal weight formulas say.
- Set a first milestone, not a final target. If you're 20 kg above the formula average, don't aim for that number straight away. Set a first goal of losing 5 to 10% of your current body weight. Research shows even a 5% reduction significantly improves blood pressure, blood sugar, and cholesterol.
- Calculate your timeline: Use our Weight Loss Calculator to map out a realistic schedule based on your calorie deficit.
- Focus on body composition, not just weight. If you're strength training, you might end up 5 kg above your "ideal weight" but with a better body fat percentage, better bloodwork, and better physical performance. That's a win.
- Reassess every 3 months. As your weight and body composition change, your goals should too. The ideal weight formula result doesn't change, but your relationship to it will.
When to Consult a Professional
These calculators are useful starting points, but see a doctor or registered dietitian if:
- Your current weight is 20+ kg above the formula range, a structured medical weight management programme (potentially including medication) may be more effective than self-directed dieting.
- You've tried to reach your ideal weight and kept failing, a dietitian can identify hidden barriers, and a doctor can check for metabolic conditions (thyroid, PCOS, insulin resistance).
- You're underweight, being significantly below the formula range carries its own health risks (osteoporosis, immune suppression, hormonal disruption). Getting help to gain weight safely is just as important as losing it.
- You have a history of eating disorders, ideal weight numbers can become obsessive triggers. A therapist specialising in eating disorders should be part of any weight goal discussion.
Related Health Tools
How to use this tool
Select your preferred unit system (Imperial or Metric)
Enter your age (for reference)
Select your gender (male or female)
Common uses
- Finding a healthy target weight based on your height and sex
- Comparing results from four different scientific formulas
- Setting a realistic weight loss or weight gain goal
- Checking if your current weight falls within a healthy range
- Understanding the BMI-based healthy weight band for your height
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Frequently Asked Questions
What is ideal body weight and how is it calculated?
Why do different formulas give different results?
Which ideal weight formula should I use?
Does ideal weight account for muscle mass?
What's a healthy weight for my height?
Is the ideal weight different for different ethnicities?
Should I aim for the lowest ideal weight number?
Does ideal weight change with age?
How does frame size affect ideal weight?
I'm above my ideal weight but my body fat is healthy, should I still lose weight?
Can being underweight be as dangerous as being overweight?
How much weight should I lose per week to reach my ideal weight?
Results are for general informational purposes only and should be checked before use. They are not professional advice. See our Disclaimer and Terms of Service.