Ideal Weight Calculator

Find your perfect weight range using scientifically validated formulas.

What Is an Ideal Weight Calculator?

An ideal weight calculator estimates the body weight that corresponds to optimal health for a given height, gender, and body frame size. It applies four well-established medical formulas, each developed from clinical research, to produce a range of ideal weight targets. The calculator then averages these results and adjusts for body frame to provide a practical reference point.

The concept of ideal body weight originated in the insurance industry, where actuaries identified weight ranges associated with the lowest mortality rates for given heights. Physicians later adopted and refined these estimates into mathematical formulas for clinical use, particularly for drug dosing, anesthesia calculations, and nutritional assessments where body weight directly affects treatment parameters.

The Four Formulas Explained

The Devine Formula (1974) is the most widely cited ideal body weight equation, originally published by Dr. B.J. Devine for calculating drug doses. For men, it starts at 110 pounds for 5 feet and adds 2.3 pounds per inch over 60 inches. For women, it starts at 100 pounds with the same 2.3-pound increment.

The Robinson Formula (1983) was developed as a refinement of Devine's work, using updated population data. It produces slightly different results, starting at 115.1 pounds for men and 104.4 pounds for women at 5 feet, with per-inch increments of 1.9 and 1.65 pounds respectively.

The Miller Formula (1983) starts at higher baseline weights of 124 pounds for men and 108.8 pounds for women but uses smaller per-inch increments of 1.41 and 1.36 pounds. This produces estimates that cluster closer together across different heights.

The Hamwi Formula (1964) is the oldest of the four and uses the largest per-inch increments at 6 pounds for men and 5 pounds for women. Starting weights are 106 and 100 pounds respectively. This formula can produce substantially higher estimates for tall individuals.

How to Use This Calculator

Choose your unit system. Select Imperial for feet and inches with results in pounds, or Metric for centimeters with results in kilograms.
Enter your height. In imperial mode, enter feet and inches separately. In metric mode, enter height in centimeters.
Select your gender. All four formulas use gender-specific coefficients, as men and women have different body composition profiles at the same height.
Select your body frame size. Choose small, medium, or large. If unsure, use medium as the default or try the wrist measurement method to determine your frame.
Review your results. The calculator displays the average ideal weight, the range across all four formulas, individual formula results, and a BMI-based healthy weight range for comparison.

Worked Examples

Example 1: Average-Height Male

A 5-foot-9 male with a medium frame. Height is 69 inches, so inches over 60 is 9. Devine gives 110 + (2.3 x 9) = 130.7 lbs. Robinson gives 115.1 + (1.9 x 9) = 132.2 lbs. Miller gives 124 + (1.41 x 9) = 136.7 lbs. Hamwi gives 106 + (6 x 9) = 160 lbs. The average is approximately 139.9 lbs.

Example 2: Tall Female with Large Frame

A 5-foot-10 female with a large frame. Height is 70 inches, inches over 60 is 10. Medium-frame values: Devine = 123 lbs, Robinson = 120.9 lbs, Miller = 122.4 lbs, Hamwi = 150 lbs. After 10% large-frame adjustment: Devine = 135.3, Robinson = 133.0, Miller = 134.6, Hamwi = 165.0. Average is approximately 142 lbs.

Example 3: Short Male with Small Frame

A 5-foot-4 male with a small frame. Height is 64 inches, inches over 60 is 4. Medium values: Devine = 119.2, Robinson = 122.7, Miller = 129.6, Hamwi = 130. After -10% small-frame adjustment: Devine = 107.3, Robinson = 110.4, Miller = 116.7, Hamwi = 117.0. Average is approximately 112.9 lbs.

Understanding the Results

The range between the lowest and highest formula estimates can span 20 or more pounds, which reflects genuine uncertainty about any single correct ideal weight. Rather than fixating on one number, use the overall range to establish reasonable upper and lower bounds for your goal weight.

The BMI-based healthy weight range provides additional context. If the formula-based ideal falls within the BMI healthy range of 18.5 to 24.9, the estimate aligns well with population-level health data. If they diverge, the BMI range may be more reliable as a general health indicator.

Tips for Using Ideal Weight Estimates

Use these numbers as starting points, not absolute targets. Individual health depends on many factors beyond weight, including body composition, fitness level, metabolic health markers, and mental wellbeing.

Track body composition rather than weight alone. Two people at the same height and weight can have dramatically different body fat percentages. Measurements like waist circumference, body fat percentage, and strength benchmarks provide more meaningful feedback than scale weight.

Consult a healthcare professional for personalized goals. A doctor or registered dietitian can evaluate your unique circumstances and set appropriate targets based on your medical history, lifestyle, and health objectives.

Be cautious about rapid weight changes. Losing more than 1 to 2 pounds per week increases the risk of muscle loss, nutritional deficiencies, and metabolic adaptation. Gradual changes are more sustainable and healthier long-term.

Frequently Asked Questions

Which ideal weight formula is the most accurate?

No single formula is definitively most accurate because ideal weight depends on individual factors like body composition, bone density, and muscle mass that simple height-based formulas cannot capture. The Devine formula is the most widely used in clinical pharmacy for drug dosing. The Robinson formula is considered a refinement of Devine. Using the average of all four formulas provides a reasonable estimate.

How does body frame size affect ideal weight?

Body frame size reflects skeletal structure, particularly bone thickness and width. A person with a large frame naturally weighs more than someone with a small frame at the same height, even at the same body fat percentage. The calculator adjusts ideal weight by approximately 10 percent up for large frames and 10 percent down for small frames relative to medium-frame baseline values.

Why do different formulas give different results?

Each formula was developed using different study populations, time periods, and methodologies. The Hamwi formula from 1964 uses the highest per-inch weight increment and may overestimate for taller individuals. The Miller formula uses the lowest increment and produces higher estimates for shorter people. These differences reflect the inherent difficulty of defining a single ideal weight for diverse body types.

Is ideal weight the same as healthy weight?

Not exactly. Ideal weight formulas estimate a target based on height and gender, while healthy weight encompasses a broader range defined by BMI between 18.5 and 24.9. You can be perfectly healthy at a weight that differs from any formula's ideal. The BMI-based healthy range shown in the results provides context for interpreting the formula estimates.

Do these formulas work for very tall or very short people?

The formulas become less reliable at extreme heights. They were developed using data from people of average height ranges and extrapolate linearly, which may not reflect reality for people under 5 feet or over 6 feet 4 inches. Very tall and very short individuals should rely more on BMI ranges, body composition measurements, and clinical assessment rather than ideal weight formulas alone.

How do I determine my body frame size?

The most common method is the wrist measurement. Wrap your thumb and middle finger around your opposite wrist. If they overlap, you have a small frame; if they just touch, medium; if there is a gap, large. A more precise method uses wrist circumference divided by height, with established ratios for each frame size and gender.

Should athletes use ideal weight calculators?

Athletes, especially those with significant muscle mass, may find that ideal weight formulas underestimate their appropriate weight. Muscle is denser than fat, so a well-trained athlete can be substantially heavier than formula estimates while maintaining low body fat. Athletes should use body fat percentage, performance metrics, and sport-specific benchmarks rather than generic ideal weight calculations.

Can I use ideal weight as a weight loss goal?

Ideal weight can serve as a general reference point, but weight loss goals should be set with a healthcare provider who considers your full medical history, body composition, and lifestyle. A more practical approach is to target a healthy BMI range and focus on sustainable habits rather than a specific number. Gradual weight loss of 1 to 2 pounds per week is safer and more sustainable than rapid approaches.