❤️ Health
⚖️ ⚖️ Ideal Weight Calculator: What Should You Weigh?
Learn how ideal body weight is calculated using the Devine formula and BMI. Understand healthy weight ranges by height, why formulas have limits, and what matters more.
⏱️ 8 min read🦉 365tool.net🌍 For everyone worldwide
There is no single "ideal" weight that applies to every person of a given height. Body weight is influenced by muscle mass, bone density, age, genetics, and overall body composition in ways that no formula can fully capture. That said, ideal weight calculations provide useful reference ranges that, combined with other health metrics, paint a meaningful picture of whether your weight is in a healthy zone.
How Ideal Body Weight is Calculated
The most widely used formula in clinical medicine is the Devine formula, developed by Dr. Ben J. Devine in 1974 primarily for drug dosing calculations. Despite its age and unscientific basis (it was created from clinical observations, not controlled research), it remains the most cited IBW formula in medical practice:
Men: IBW (kg) = 50 + 2.3 × (height in inches − 60)
Women: IBW (kg) = 45.5 + 2.3 × (height in inches − 60)
Example: 5'8" (68 inches) Male
- IBW = 50 + 2.3 × (68 − 60) = 50 + 2.3 × 8 = 50 + 18.4 = 68.4 kg (150.7 lbs)
Example: 5'4" (64 inches) Female
- IBW = 45.5 + 2.3 × (64 − 60) = 45.5 + 9.2 = 54.7 kg (120.6 lbs)
Other Common Ideal Weight Formulas
Multiple formulas exist, each developed by different researchers for different populations. They give similar but not identical results:
| Formula |
Men IBW (5'8") |
Women IBW (5'4") |
| Devine (1974) | 68.4 kg (150.7 lbs) | 54.7 kg (120.6 lbs) |
| Robinson (1983) | 69.1 kg (152.3 lbs) | 56.1 kg (123.7 lbs) |
| Miller (1983) | 71.4 kg (157.4 lbs) | 58.9 kg (129.9 lbs) |
| BMI Method (BMI 22) | 71.4 kg (157 lbs) | 58.2 kg (128 lbs) |
The BMI-Based Approach: Healthy Weight Range
Rather than a single ideal weight, the BMI method gives a healthy weight range corresponding to a BMI of 18.5–24.9. This is arguably more useful than a single number:
Healthy Weight Range = height (m)² × 18.5 to height (m)² × 24.9
Example: 5'8" = 1.727 m
- Lower bound: 1.727² × 18.5 = 2.98 × 18.5 = 55.2 kg (121.6 lbs)
- Upper bound: 1.727² × 24.9 = 2.98 × 24.9 = 74.2 kg (163.6 lbs)
- Healthy range for a 5'8" person: 121–164 lbs
Height-Weight Reference Table
| Height |
IBW Men (Devine) |
IBW Women (Devine) |
BMI Healthy Range |
| 5'0" (152 cm) | 50 kg (110 lbs) | 45.5 kg (100 lbs) | 43–58 kg (95–128 lbs) |
| 5'4" (163 cm) | 59.2 kg (130 lbs) | 54.7 kg (121 lbs) | 49–66 kg (108–145 lbs) |
| 5'8" (173 cm) | 68.4 kg (151 lbs) | 63.9 kg (141 lbs) | 55–74 kg (122–163 lbs) |
| 6'0" (183 cm) | 77.6 kg (171 lbs) | 73.1 kg (161 lbs) | 62–84 kg (136–185 lbs) |
Why Ideal Weight Formulas Have Significant Limitations
They ignore muscle mass
A competitive bodybuilder at 5'10" and 210 lbs with 8% body fat would be classified as "obese" by BMI and significantly above ideal weight by Devine formula. Yet their body composition is highly healthy. Muscle is denser than fat — highly muscular people will always read "too heavy" on standard formulas.
They ignore bone density and frame size
People with denser bones (common in certain ethnicities and those who do weight-bearing exercise) naturally weigh more. Large-framed individuals (wide shoulders, large wrists) have a higher healthy weight than small-framed people of the same height.
The formulas weren't derived scientifically
The Devine formula was created from clinical observation to approximate drug clearance, not to identify the optimal health weight. Its widespread use is largely historical convenience, not scientific validation.
Better Metrics Than Scale Weight Alone
Rather than fixating on a single "ideal" number, combine multiple metrics for a more complete picture:
- Body fat percentage: More meaningful than scale weight; reflects actual composition
- Waist circumference: Above 102 cm (men) or 88 cm (women) indicates elevated metabolic risk regardless of BMI or IBW
- Waist-to-height ratio: Should be below 0.5 for most adults
- Fitness level: Can you climb stairs without losing breath? Exercise regularly? These functional measures often predict longevity better than weight
❓ Frequently Asked Questions
How is ideal body weight calculated?▼
The most common formula is the Devine formula: Men IBW (kg) = 50 + 2.3 × (height in inches − 60); Women IBW (kg) = 45.5 + 2.3 × (height in inches − 60). A 5'8" man has a Devine IBW of 68.4 kg (150.7 lbs). A 5'4" woman has an IBW of 54.7 kg (120.6 lbs). These are reference points, not precise targets.
What is a healthy weight range for my height?▼
A BMI between 18.5 and 24.9 is considered healthy for most adults. To calculate: multiply your height in meters squared by 18.5 (lower bound) and 24.9 (upper bound). For a 5'8" person: healthy range is approximately 55–74 kg (121–163 lbs). This range reflects the middle 80% of adults at that height with healthy body composition.
Why do different ideal weight formulas give different results?▼
The Devine, Robinson, Miller, and Hamwi formulas were each developed from different populations and for different purposes. None has a strong scientific basis — they were clinical approximations. The differences between them are typically 5–10 lbs. No single formula is definitively more accurate, which is why using a healthy BMI range is often more informative than a single IBW number.
Is ideal body weight a reliable health indicator?▼
It has significant limitations. IBW formulas ignore muscle mass, bone density, age, and body composition. A muscular athlete and an obese sedentary person can have the same IBW. Body fat percentage, waist circumference, and waist-to-height ratio are generally better health indicators. Use IBW as one reference point among several, not as a definitive health target.
How do I know if my weight is healthy?▼
Consider multiple measures: Is your BMI in the healthy range (18.5–24.9)? Is your body fat percentage in a healthy range (18–24% men, 25–31% women)? Is your waist circumference below 102 cm (men) or 88 cm (women)? Can you exercise comfortably and maintain daily activities? No single number tells the whole story — trends over time and how you feel physically matter significantly.