Ideal Weight Calculator

Determining your ideal body weight is more nuanced than simply looking at a number on a chart. While height is the primary factor, your frame size, muscle mass, gender, age, and personal health goals all play important roles. Our Ideal Weight Calculator uses multiple scientifically established formulas to provide you with a healthy weight range rather than a single rigid number, giving you the flexibility to choose a target that aligns with your unique body type and lifestyle.

The concept of ideal body weight has evolved significantly over time. Early formulas were developed for medical dosing purposes—doctors needed to estimate appropriate medication doses based on body size. Over time, researchers correlated certain weight ranges with longevity and reduced disease risk, creating standards for healthy weight. Today, we understand that ideal weight is not one-size-fits-all, but rather a range that accounts for individual variation.

Several formulas are commonly used to calculate ideal body weight. The Devine formula, developed in 1974, is one of the most widely referenced. For men: IBW (kg) = 50 + 2.3 × (height in inches - 60). For women: IBW (kg) = 45.5 + 2.3 × (height in inches - 60). This formula assumes average frame size and has been used extensively in both research and clinical settings.

The Robinson formula (1983) is similar but uses slightly different coefficients. For men: IBW (kg) = 52 + 1.9 × (height in inches - 60). For women: IBW (kg) = 49 + 1.7 × (height in inches - 60). The Miller formula (1983) offers another variation. These slightly different approaches demonstrate that ideal weight is an estimate, not a precise prescription.

The Hamwi formula is another popular method. For men: 106 pounds for the first 5 feet of height, plus 6 pounds for each additional inch. For women: 100 pounds for the first 5 feet, plus 5 pounds for each additional inch. Adjustments of 10% are made for frame size—subtract 10% for small frames and add 10% for large frames. Determining frame size is typically done by measuring wrist circumference or elbow breadth.

Body frame size is an important but often overlooked factor. People with larger skeletal structures naturally weigh more than those with smaller frames, even at the same height and body fat percentage. To estimate your frame size, wrap your thumb and middle finger around your wrist. If they overlap significantly, you have a small frame. If they just touch, you have a medium frame. If they do not meet, you have a large frame. More precise measurements involve elbow breadth with calipers.

It is critical to understand that these formulas calculate lean, healthy weight for average body compositions. They do not account for athletes with significant muscle mass, who will weigh more than the calculated ideal weight yet be extremely healthy. Muscle is denser than fat, weighing more per unit of volume. A bodybuilder and a sedentary person of the same height may have drastically different weights, but the muscular individual is far healthier despite being heavier than their calculated ideal body weight.

Conversely, someone can be within their ideal weight range but still have unhealthy body composition if they have low muscle mass and high body fat percentage—a condition called normal weight obesity or skinny fat. This highlights why ideal weight should be considered alongside other metrics like body fat percentage, waist circumference, and overall fitness level. Health is multidimensional, not reducible to a single number on the scale.

Historical weight tables from insurance companies, such as the Metropolitan Life tables, were based on policyholders who lived the longest. These tables showed that people slightly below average weight had the best longevity outcomes. However, these tables have limitations—they did not account for smoking status, fitness level, or chronic diseases. Modern research suggests that being slightly above historical ideal weights may actually be associated with better outcomes in older adults, possibly because some weight reserve is protective during illness.

Age is another consideration. As we age, maintaining some additional weight may be beneficial for bone health and resilience. Older adults who are too thin face higher risks of frailty, osteoporosis, and poor recovery from illness or injury. The ideal weight for a seventy-year-old may be a bit higher than for a thirty-year-old of the same height, reflecting these physiological differences.

Setting a target weight should be a personal decision informed by science but tailored to your circumstances. Consider your history—what weight did you feel your best at? What weight can you maintain without extreme restriction or constant hunger? A sustainable, healthy lifestyle is far more valuable than achieving a number that requires misery to maintain. Many people find that focusing on performance goals (strength, endurance, energy) and health markers (blood pressure, cholesterol, blood sugar) is more motivating and meaningful than scale weight.

Use this calculator as a guideline, not a commandment. If you are currently outside the suggested range, approach weight change gradually. Losing one to two pounds per week through a combination of modest calorie reduction and increased physical activity is safe and sustainable. Rapid weight loss often results in muscle loss, metabolic slowdown, and rebound weight gain. If you are significantly underweight, work with a healthcare provider or registered dietitian to gain weight healthily through nutrient-dense foods and strength training, rather than empty calories.

Key Benefits:

• Calculate healthy weight range using multiple scientific formulas
• Adjust for body frame size (small, medium, large)
• Understand ideal weight for your height and gender
• Set realistic, healthy weight loss or gain targets
• Account for individual variation in body composition
• Avoid unrealistic or unhealthy weight expectations
• Learn how age and muscle mass affect ideal weight
• Use as a guideline for sustainable health goals