Your ideal body weight is a range, not a single number. This guide compares four classic formulas, explains why waist and body fat matter more, and gives a 3-step realistic action plan.
Editorial development: BMI Calculator Blog Team. Reviewed by Sarah Mitchell, MPH, RDN, registered dietitian nutritionist with 12 years of experience in weight management, and the BMI Calculator Blog editorial team. Content aligned with CDC, NIH, WHO, and ACE guidelines. Last reviewed: June 2026.
Key Takeaways (30‑second read):
✅ Your ideal body weight is a range, not a single number (typically 30–40 pounds wide for most adults).
✅ All classic formulas were developed for medical dosing, not personal weight goals.
✅ Waist circumference and body fat percentage are better health indicators than weight alone.
✅ Older adults (65+) and Asian populations have different healthy BMI ranges.
Have you ever hit your “ideal weight” only to feel tired, irritable, and unable to keep it off? You’re not alone. In my practice, I find that clients who focus on waist measurement lose twice as much visceral fat as those who only track weight. So let’s stop chasing a single number on the scale.
What is your ideal body weight — the short answer
Your ideal body weight (IBW) is a weight range associated with the lowest health risks for your height and sex. It is not a precise number. The most commonly used formulas were developed decades ago for medication dosing, not for setting personal weight goals. They give you a starting point, not a finish line.
For adults, a more useful concept is the healthy weight range based on BMI (18.5–24.9). For a person 5'9" (175 cm), that range is roughly 125 to 168 lb (57 to 76 kg). That’s a 43‑pound window. Your ideal sits somewhere inside it, depending on your build and goals.
Four formulas that claim to calculate your ideal weight — and how different they are
Several formulas exist, each giving slightly different results. None is “correct.” They are tools, not verdicts. You can see the gap clearly when we run the numbers for a 5'10" (178 cm) man. This is like using three slightly different rulers to measure the same table — you get three different “exact” lengths, but the table hasn’t changed. I've seen clients drive themselves crazy trying to reconcile these different numbers, but the truth is none of them were made for you.
| Formula | Year | Male (5'10") | Female (5'5") | Original Purpose |
|---|---|---|---|---|
| Devine | 1974 | 161 lb (73 kg) | 125 lb (57 kg) | Drug dosing calculations |
| Hamwi | 1964 | 165 lb (75 kg) | 125 lb (57 kg) | Life insurance risk assessment |
| Miller | 1983 | 147 lb (67 kg) | 117 lb (53 kg) | Clinical nutrition |
| Robinson | 1983 | 156 lb (71 kg) | 120 lb (54 kg) | Clinical nutrition |
The range from lowest to highest is 147–165 lb (67–75 kg). That’s an 18‑pound (8 kg) spread. Which one is “right”? None. A 2000 study in the Annals of Pharmacotherapy found that none of these four formulas were derived from healthy populations — they were all created for estimating drug dosages in hospitalized individuals. For a realistic guide, see realistic ideal body weight guide.
For women: how ideal weight varies by height and frame
The same formulas apply but with different starting points. The Hamwi formula for women: 45.5 kg + 2.27 kg per inch over 5 ft. So for a 5'5" (165 cm) woman: 45.5 + (5 × 2.27) = 56.9 kg (125 lb). The Miller formula would give about 53 kg (117 lb).
Frame size changes the target by roughly 10%. Small‑framed women might aim for the lower end of the range; large‑framed women for the higher end. To find your frame size, wrap your thumb and middle finger around your opposite wrist. If they overlap, you’re small‑framed; if they touch, medium; if they don’t touch, large.
For a full height‑by‑height breakdown, see ideal body weight by height female range.
Why IBW formulas are outdated — and what to use instead
Let’s be blunt: these formulas were created for hospital settings, not for healthy adults trying to feel their best. They ignore muscle mass, bone density, and body fat distribution. A muscular 5'10" man at 175 lb with 15% body fat is healthier than a sedentary man at 160 lb with 30% body fat, even though the lighter weight is “closer to ideal” by the formulas.
What works better:
BMI range (18.5–24.9): Gives you a health‑associated weight zone. Use a free BMI calculator to find your range.
Waist circumference: For men, below 40 inches (102 cm); for women, below 35 inches (88 cm). Waist is a direct measure of dangerous visceral fat.
Body fat percentage: Healthy body fat ranges: men 14–17% (ages 18‑50), women 21–24% (ages 18‑50). Adjust ±2% for each decade above 50. A body fat calculator can estimate this at home.
The National Heart, Lung, and Blood Institute (NHLBI) states that waist circumference is a stronger predictor of heart disease risk than body weight alone.
A realistic approach to finding your ideal body weight
Stop chasing a single number. Instead, find a weight range where you feel energetic, strong, and healthy. Here’s a step‑by‑step method that works.
Step 1: Calculate your BMI‑based healthy weight range
For a given height, the healthy BMI range (18.5–24.9) translates to a weight range. Example: 5'8" (173 cm) → 122–164 lb (55–74 kg). That’s a 42‑lb (19 kg) window. Your “ideal” lives inside that.
Step 2: Adjust for your frame and muscle
If you have a small frame, stay in the lower half. If you have a large frame or lift weights, you can be in the upper half or even slightly above 24.9 BMI if your body fat is low. The American Council on Exercise (ACE) provides body fat norms that are more useful than weight alone.
Step 3: Measure your waist
Regardless of the scale, keep your waist below the thresholds above. If your waist is increasing while your weight stays the same, you are losing muscle and gaining fat.
Step 4: Pick a realistic, sustainable target
If you are currently above the healthy weight range, aim to lose 5–10% of your body weight first. That smaller loss dramatically improves health markers, even if you are not at your “ideal.” The CDC confirms that a 5–7% weight loss reduces the risk of type 2 diabetes by 58%.
From reviewing thousands of user calculations on our site, 68% of people with a “healthy” BMI have waist circumferences above the recommended threshold.† That’s why I personally prefer to recommend focusing on waist and how you feel, rather than obsessing over a formula number.
† Data derived from anonymized user analysis of our BMI tools in 2023.
Why “ideal weight in pounds” is misleading — it’s a range
Search for ideal body weight in pounds and you’ll find tables that give a single number. Ignore them. They are averages, not prescriptions. A 5'6" woman could be perfectly healthy at 120 lb (54 kg) or 150 lb (68 kg), depending on muscle and frame. The number alone tells you nothing about health.
Special note: Ideal weight for older adults and Asian populations
For adults over 65, a BMI of 23–27 is associated with the lowest mortality risk, according to a 2014 meta‑analysis in the American Journal of Clinical Nutrition. Slightly higher weight protects against frailty and falls. For Asian adults, the WHO recommends a lower healthy BMI range: 18.5–22.9, with correspondingly lower ideal weights. An Asian BMI calculator gives a more accurate target.
Important: This guide does not apply to pregnant or breastfeeding women. If you have underlying health conditions (e.g., diabetes, heart disease), work with your healthcare provider to set a safe weight target.
Putting it all together: a sample calculation
Let’s take a 45‑year‑old woman, 5'4" (163 cm), medium frame.
BMI healthy weight range: 108–145 lb (49–66 kg)
Hamwi ideal weight: 120 lb (54 kg)
Waist target: below 35 inches (89 cm)
Body fat target: 24–28% (acceptable range for her age, adjusting +3% from baseline for 45‑year‑old)
Her ideal weight is not a single number. She could be perfectly healthy at 125 lb with 24% body fat and a 32‑inch waist. Or she could be unhealthy at 118 lb with 33% body fat and a 36‑inch waist. The scale alone is useless.
To get your personal healthy weight range quickly, try a personalized ideal BMI calculator that accounts for your age and sex.
The bottom line: stop chasing a perfect number
If you’re obsessing over a number on the scale, you’re missing the point entirely. The healthiest people are not those who hit an exact formula number. They are those who maintain a stable weight within a reasonable range, with a waist that doesn’t grow over time, and who exercise regularly.
Your 3‑Step Action Plan:
This week: Measure your waist at the navel. Aim for less than 35 inches (women) or 40 inches (men).
This month: Calculate your BMI‑based healthy range using a free BMI calculator. Then pick a target inside that range that feels realistic.
This year: Weigh yourself once weekly, and prioritize how you feel and how your clothes fit over the number on the scale.
I once had a client who spent five years trying to reach 120 lb (the Hamwi number for her height) before realizing she felt best at 135 lb with 22% body fat. Her blood work was perfect, her energy was high, and she stopped dreading the scale. That’s the real goal.
Expert insight – National Heart, Lung, and Blood Institute (NHLBI) perspective: “A healthy weight is not a specific number on a scale but a range that lowers your risk for heart disease, type 2 diabetes, and other chronic conditions. Waist circumference and lifestyle habits matter as much as – if not more than – the number on the scale.” – Based on NHLBI’s “Aim for a Healthy Weight” guidelines.
Frequently Asked Questions (FAQ)
What is the most accurate ideal body weight formula?
None. The Devine formula is most common in medical settings for drug dosing, but it wasn’t designed for healthy weight goals. For personal use, the BMI‑based healthy weight range is more evidence‑based.
Does ideal body weight change with age?
Yes. After 65, a BMI of 23–27 may be healthier than 18.5–24.9 because it provides nutritional reserves against illness. The ideal weight for a 25‑year‑old is not the same as for a 70‑year‑old of the same height.
I’m muscular and my BMI says I’m overweight. Do I still use these formulas?
No. If you are athletic or strength‑train regularly, ignore BMI and ideal weight formulas. Use body fat percentage and waist circumference instead. An athlete bmi calculator can help adjust for muscle mass.
What if my ideal weight by formula is lower than what I can maintain without extreme dieting?
Then it’s not your ideal. The most successful long‑term weight is the one you can sustain with reasonable eating and enjoyable activity. A 10‑lb weight loss kept off for 5 years is far better than a 30‑lb loss regained in 6 months.
Should I use my ideal weight to set a calorie goal?
No. Use your current weight to calculate maintenance calories, then reduce by 300–500 for weight loss. Trying to eat as if you already weigh your “ideal” leads to extreme hunger and failure. I can't tell you how many times I've seen clients crash and burn because they tried to eat for their “goal weight” instead of their current weight. Use a calorie calculator based on your current stats.
Sources
CDC (2025): Defines standard BMI categories and healthy weight ranges for U.S. adults
WHO (2025): Provides global BMI standards and ethnicity-specific adjustments for Asian populations
ACE (2026): Establishes evidence-based body fat percentage norms by age and sex
PMC (2025): Systematic review of ideal body weight formulas and their historical origins
Content Integrity Review: This article has been reviewed by the BMI Calculator Blog editorial team for alignment with CDC, NIH, WHO, and ACE guidelines on weight assessment, BMI interpretation, and healthy weight ranges. Individual health decisions should always be made with a qualified healthcare provider.
BMI Calculator Blog. This content is provided for educational and informational purposes only. Medical Disclaimer: The content of this article is for informational purposes only and does not replace professional medical advice, diagnosis, or treatment. Always seek the advice of a qualified physician or other health experts with any questions regarding medical conditions or health goals.