Ideal Weight Calculator

Calculate your ideal body weight using multiple clinical formulas and BMI-based healthy weight ranges. Get evidence-based targets for your health goals.

⚖️ Ideal Weight Calculator

What is an Ideal Weight Calculator?

An ideal weight calculator estimates your ideal body weight (IBW) or healthy weight range based on your height, sex, and sometimes age. It uses standard clinical formulas (Devine, Hamwi, Miller, Robinson) and BMI-based healthy weight ranges to provide evidence-based targets.

This tool helps you quickly see whether your current weight is below, within, or above commonly used healthy ranges, and how much you might need to gain or lose to fall within those ranges. It's designed as a screening tool to support health conversations with professionals.

Remember that ideal weight is just one measure of health. Body composition, fitness level, waist circumference, and overall metabolic health are equally important factors to consider alongside these calculations.

How to Use This Calculator

Select your preferred unit system (US Units or Metric Units)
Enter your age (between 2 and 80 years)
Select your biological sex (Male or Female)
Enter your height in feet and inches (US) or centimeters (Metric)
Click 'Calculate Ideal Weight' to see your results from multiple formulas and the healthy BMI range

Latest Research & Clinical Insights

What This Calculator Provides

Our calculator gives you a comprehensive view of ideal weight by showing:

Formula-based IBW: Four classic clinical equations (Devine, Hamwi, Miller, Robinson) that estimate a single 'ideal' weight from your height and sex.
BMI-based healthy range: Weight range corresponding to a BMI of 18.5–24.9 kg/m², the most widely used clinical range for 'healthy weight'.
Multiple perspectives: Comparisons across formulas help you see the spread and avoid over-focusing on one exact number.

Why This Tool is Useful

Ideal weight calculators serve several important purposes:

Fast health screening: Provides a quick, accessible tool to flag potential underweight, overweight, or obesity-related risk.
Evidence-based goal-setting: Supports weight management by offering science-backed targets instead of arbitrary goals.
Clinical applications: Assists in medical contexts like medication dosing, anesthesia planning, and nutrition support where IBW is part of standard calculations.

Research & Guidelines Context

Understanding the science behind ideal weight calculations:

Classic IBW formulas: Hamwi (1964), Devine (1974), Miller (1983), and Robinson (1983) were originally developed mainly for drug-dosing and clinical use, not for cosmetic or aesthetic targets.
BMI-based healthy ranges: The 18.5–24.9 range is endorsed by major health organizations (NHLBI, CDC, NIDDK) as a practical way to define healthy weight for adults at the population level.
Health risks of deviation: Weights significantly above healthy ranges are associated with higher risks of type 2 diabetes, hypertension, fatty liver disease, stroke, sleep apnea, cardiovascular disease, and some cancers.
Waist circumference matters: Measurements ≥35 inches (women) or ≥40 inches (men) indicate higher cardiometabolic risk even at the same BMI/weight.

Important Limitations

Be aware of these limitations when interpreting your results:

IBW and BMI-based tools do not account for body composition (fat vs. muscle), bone density, ethnicity, age-related changes, or fitness level.
Muscular or athletic individuals may be classified as overweight/obese despite low body fat.
IBW gives a single number, which can be misleading; many clinicians prefer to work with a range tailored to the individual.
These tools are less accurate at the extremes of height, age (e.g., very old adults), and for some ethnic groups whose risk curves differ at similar BMI/weight.

Best Practices for Using This Calculator

Treat the result as a rough screening guide, not a prescription; being somewhat above or below the calculated 'ideal' can still be compatible with good health.
Focus on a healthy range plus trends over time (weight, waist circumference, fitness, labs) rather than chasing one exact number.
Combine calculator results with waist circumference, lifestyle factors (diet quality, physical activity, sleep), and clinical markers (blood pressure, lipids, blood glucose).
If you have chronic disease, are pregnant, or have a history of eating disorders, discuss targets with a clinician or registered dietitian rather than using generic formulas alone.
Remember that formulas were originally for clinical dosing and do not represent a beauty standard or moral judgment. Gradual, sustainable changes are superior to rapid weight loss.

Understanding the Formulas

The Four Classic IBW Formulas

Each formula uses a slightly different approach to estimate ideal weight:

Robinson (1983): For men: 52 kg + 1.9 kg per inch over 5 feet. For women: 49 kg + 1.7 kg per inch over 5 feet.
Miller (1983): For men: 56.2 kg + 1.41 kg per inch over 5 feet. For women: 53.1 kg + 1.36 kg per inch over 5 feet.
Devine (1974): For men: 50 kg + 2.3 kg per inch over 5 feet. For women: 45.5 kg + 2.3 kg per inch over 5 feet.
Hamwi (1964): For men: 48 kg + 2.7 kg per inch over 5 feet. For women: 45.5 kg + 2.2 kg per inch over 5 feet.

BMI-Based Healthy Weight Range

The BMI-based range is calculated using the formula: BMI = weight (kg) / height (m)². A healthy BMI is considered to be between 18.5 and 24.9.

This range gives you a weight span rather than a single number, which is often more realistic and achievable. It accounts for individual variation in body frame and composition.

Interpreting Your Results

When you receive your results, consider the following:

Significantly above all ranges: May warrant discussing cardiometabolic risk and potential lifestyle changes with a health professional.
Significantly below all ranges: Important to screen for undernutrition, chronic illness, or disordered eating.
Within or close to ranges: Focus on maintaining healthy behaviors rather than fixating on additional weight loss.

Beyond the Numbers

Always consider how you feel, function, and perform (energy, strength, endurance, menstrual health, sleep) alongside numeric targets. Health is multidimensional and cannot be fully captured by weight alone.

Frequently Asked Questions

Are all the formulas equally accurate?

No single formula is definitively 'most accurate' because ideal weight varies by individual. The formulas were developed for different clinical purposes and populations. Viewing results from multiple formulas gives you a range to consider rather than a single target.

Why do the formulas give different results?

Each formula was developed using different populations and methodologies. The variation reflects the reality that there's no single 'perfect' ideal weight—rather, a healthy range that depends on many individual factors.

Should I aim for the lowest number shown?

No. The goal is not to achieve the lowest possible weight, but to find a sustainable weight within a healthy range where you feel good, function well, and maintain good health markers. Focus on the BMI-based range as a realistic target.

Can I use this calculator if I'm very muscular?

These formulas don't account for muscle mass. If you're very muscular or athletic, you may weigh more than the 'ideal' but still be very healthy. Consider body composition analysis and waist circumference as additional measures.

Is this calculator suitable for children or elderly adults?

This calculator accepts ages 2-80, but the formulas are most accurate for adults aged 18-65. For children, use pediatric growth charts. For elderly adults, consult a healthcare provider as age-related changes affect ideal weight.

What if my current weight is very different from the results?

Don't panic. Use this as a starting point for conversation with a healthcare provider. Gradual, sustainable changes (0.5-2 lbs per week) are healthier than rapid weight loss. Focus on improving health behaviors regardless of the scale.

Should I consider waist circumference too?

Yes! Waist circumference is an important measure of abdominal fat and cardiometabolic risk. Even at a 'healthy' weight, excess abdominal fat (≥35 inches for women, ≥40 inches for men) increases health risks.

Can I use this calculator during pregnancy?

No. Pregnancy requires different weight guidelines based on pre-pregnancy BMI. Consult your healthcare provider for appropriate pregnancy weight gain recommendations.