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Ideal Weight Calculator

Ideal Weight Calculator

Personal Info
Height

Weight Results

Robinson
kg
1983 formula
Miller
kg
1983 formula
Devine
kg
1974 formula
Hamwi
kg
1964 formula
Peterson
kg
2016 formula
Healthy BMI Range
kg
BMI 18.5 – 24.9
History
DateAgeGenderHeightAvg WeightBMI RangeActions

Ideal Weight Calculator: Find Your Healthy Weight Range

Introduction

Finding your ideal weight isn't about achieving a perfect number, but rather discovering a healthy range that supports your overall well-being. Our Ideal Weight Calculator uses multiple scientific formulas to give you a comprehensive view of what weight range might be healthiest for your body.

This tool combines five different formulas — Robinson, Miller, Devine, Hamwi, and Peterson — developed between 1964 and 2016. It also provides the healthy weight range based on Body Mass Index (BMI) standards, giving you a complete picture of your healthy weight possibilities.

How to Use This Calculator

Step 1: Select Your Units

Choose between Metric (cm, kg) or Imperial (ft/in, lbs) measurement systems.

Step 2: Enter Personal Information

  • Age: Enter your age (2-80 years). Age affects the Peterson formula.
  • Gender: Select Male or Female — formulas differ for each.
  • Height: Enter your height in cm (Metric) or feet/inches (Imperial).

Step 3: Calculate and Review

Click Calculate to see your ideal weight from all five formulas and the healthy BMI range.

Pro Tip: Consider the Range

When you get different results from different formulas, don't be concerned. Consider the range of results rather than focusing on any single number. The average of all formulas gives you a balanced estimate.

The 5 Formulas Explained

1. Robinson Formula (1983)

Men: 52 kg + 1.9 kg per inch over 5 feet

Women: 49 kg + 1.7 kg per inch over 5 feet

Men: 52 + 1.9 × (height in inches - 60)
Women: 49 + 1.7 × (height in inches - 60)

Developed by Dr. Robinson in 1983, this formula is based on statistical analysis of healthy weight ranges and is widely used in medical settings.

2. Miller Formula (1983)

Men: 56.2 kg + 1.41 kg per inch over 5 feet

Women: 53.1 kg + 1.36 kg per inch over 5 feet

Men: 56.2 + 1.41 × (height in inches - 60)
Women: 53.1 + 1.36 × (height in inches - 60)

Also developed in 1983, the Miller formula tends to give slightly higher estimates than Robinson's formula, particularly for taller individuals.

3. Devine Formula (1974)

Men: 50 kg + 2.3 kg per inch over 5 feet

Women: 45.5 kg + 2.3 kg per inch over 5 feet

Men: 50 + 2.3 × (height in inches - 60)
Women: 45.5 + 2.3 × (height in inches - 60)

One of the oldest formulas still in use, the Devine formula was originally developed for medical dosage calculations.

4. Hamwi Formula (1964)

Men: 48 kg + 2.7 kg per inch over 5 feet

Women: 45.5 kg + 2.2 kg per inch over 5 feet

Men: 48 + 2.7 × (height in inches - 60)
Women: 45.5 + 2.2 × (height in inches - 60)

Developed by Dr. Hamwi in 1964, this formula was one of the first to provide a simple method for calculating ideal body weight.

5. Peterson Formula (2016)

Base: Same as Devine formula with age adjustments

Age 50+: Multiply base by 0.98
Age 60+: Multiply base by 0.97

The most recent formula in our calculator, the Peterson formula accounts for natural changes in body composition that occur with aging.

Understanding BMI & Healthy Weight

What is BMI?

Body Mass Index (BMI) is a measure of body fat based on height and weight. It's calculated by dividing weight in kilograms by height in meters squared.

Formula: BMI = weight (kg) / height (m)²

The World Health Organization defines healthy BMI ranges as:

  • Underweight: BMI less than 18.5
  • Normal weight: BMI 18.5 to 24.9
  • Overweight: BMI 25 to 29.9
  • Obese: BMI 30 or greater

BMI Limitations

While BMI is a useful screening tool, it has limitations. It doesn't distinguish between muscle and fat, so athletes with high muscle mass may have a high BMI despite being very fit. Always consider body composition alongside BMI.

Worked Example

Example Calculation

A 5'9" (69 inch) man using the Robinson formula:

Robinson Formula: 52 + 1.9 × (69 - 60) = 52 + 17.1 = 69.1 kg

For the same height, the five formulas would give:

  • Robinson: 69.1 kg
  • Miller: 68.1 kg
  • Devine: 70.7 kg
  • Hamwi: 72.3 kg
  • Peterson: 70.7 kg (age 23, no adjustment)

Average: 70.2 kg | Healthy BMI Range: 58.6 – 79.1 kg

This shows how the formulas provide a range of estimates, all falling within the healthy BMI range.

Interpreting Your Results

Multiple Formulas, One Picture

When you get different results from different formulas, don't be concerned. This is normal. Consider the range of results rather than focusing on any single number.

Setting Realistic Goals

If your current weight is outside the suggested ranges:

  • Small changes: Aim for gradual weight changes of 0.5-1 kg (1-2 lbs) per week.
  • Focus on health: Prioritize nutritious eating and regular activity over rapid weight loss.
  • Consult professionals: Talk to a doctor or dietitian for personalized advice.

Beyond the Scale

Remember that weight is just one indicator of health. Other factors like blood pressure, cholesterol levels, physical fitness, and how you feel are equally important.

Tips for a Healthy Weight Journey

  • Focus on Nutrition: Choose whole foods over processed options.
  • Stay Active: Aim for at least 150 minutes of moderate exercise per week.
  • Get Enough Sleep: Poor sleep can affect weight and overall health.
  • Manage Stress: Chronic stress can lead to weight gain.
  • Stay Hydrated: Drink plenty of water throughout the day.
  • Be Patient: Sustainable weight changes take time.

Common Mistakes to Avoid

  • Focusing on One Number: No single number defines your health.
  • Ignoring Muscle Mass: Muscle weighs more than fat.
  • Comparing to Others: Every body is unique.
  • Extreme Dieting: Quick fixes rarely work long-term.
  • Not Consulting Healthcare Providers: Always seek professional guidance.

Frequently Asked Questions

Different formulas were developed using different population studies and methodologies. Some formulas are based on statistical averages, while others were designed for specific medical applications. The variation is normal and expected.
No single formula is universally "most accurate" for everyone. The Peterson formula (2016) is the most recent and includes age adjustments, making it potentially more relevant for many people. However, considering the range from all formulas gives you the most comprehensive picture.
As we age, our body composition naturally changes — we tend to lose muscle mass and gain fat, even if our weight stays the same. The Peterson formula accounts for these changes by slightly adjusting the ideal weight for people over 50 and 60.
Men and women typically have different body compositions. Men generally have more muscle mass and less body fat than women of the same height and weight. The formulas account for these physiological differences.
If you have high muscle mass, these formulas might underestimate your healthy weight. Muscle weighs more than fat, so athletes often weigh more than these formulas suggest while being perfectly healthy. In such cases, body composition measurements (like body fat percentage) are more meaningful than weight alone.
Your ideal weight changes very slowly over time (mainly with age). There's no need to recalculate frequently unless you've experienced significant height changes or want to track how the formulas change as you age.
While the calculator accepts ages 2-80, the formulas were primarily developed for adults. For children and teenagers, growth charts and pediatric BMI percentiles are more appropriate tools as they account for normal growth patterns.
The BMI range provides context for the formula results. While the formulas estimate ideal weight based on height and gender, BMI relates weight to height in a standardized way that's widely used in healthcare settings worldwide.
If your current weight is significantly outside the suggested ranges, consider consulting with a healthcare provider. They can help you understand if weight changes would benefit your health and create a safe, personalized plan if needed.
The formulas tend to be most accurate for people of average height. For very tall or very short individuals, the estimates may be less reliable. This is another reason why considering the range from multiple formulas is helpful.
These formulas are not designed for pregnancy. Weight gain during pregnancy is normal and necessary. Pregnant individuals should follow their healthcare provider's guidance about appropriate weight gain based on their pre-pregnancy weight.
Saving calculations lets you track how your ideal weight range changes over time (mainly due to aging). It also allows you to compare different scenarios, like how changing your height measurement slightly affects the results.
The calculator works with both measurement systems. Metric uses centimeters for height and kilograms for weight. Imperial uses feet/inches for height and pounds for weight. The formulas themselves were originally developed using imperial measurements.
Absolutely! The export features (TXT, HTML, PDF) make it easy to share your results with healthcare providers. This can be helpful for discussions about weight management and overall health.