Find Predicted Weight Calculator Stats

Estimate your ideal or predicted weight based on your height and gender using our Predicted Weight Calculator. See stats from different formulas and understand the factors involved.

Chart showing Predicted Weight and Healthy Range based on the Hamwi formula.

Formula	Predicted Weight (kg)	Predicted Weight (lbs)
Hamwi	–	–
Devine	–	–
Robinson	–	–
Miller	–	–

Comparison of predicted ideal body weight using different formulas.

What is a Predicted Weight Calculator?

A Predicted Weight Calculator is a tool used to estimate an individual’s ideal or healthy body weight based primarily on their height and gender. It uses established formulas developed by researchers to provide a weight range that is generally considered healthy for a person of a given stature. These calculators are also often referred to as Ideal Body Weight (IBW) calculators.

Who should use it? Individuals interested in understanding a general healthy weight range for their height, fitness enthusiasts setting weight goals, and healthcare professionals as a quick reference point (though they would consider many more factors). It’s a starting point for discussion about healthy weight.

Common misconceptions include believing the result is a strict target everyone must achieve. In reality, ideal weight varies based on body composition (muscle vs. fat), frame size, age, and individual health conditions. The Predicted Weight Calculator provides an estimate, not a definitive health diagnosis.

Predicted Weight Formulas and Mathematical Explanation

Several formulas are used by a Predicted Weight Calculator to estimate ideal body weight (IBW). Here are some of the most common ones:

Hamwi Formula (1964)

Often used as a quick estimate.

• Men: 48.0 kg + 2.7 kg for each inch over 5 feet
• Women: 45.5 kg + 2.2 kg for each inch over 5 feet

Devine Formula (1974)

Originally developed for drug dosage calculations based on weight.

• Men: 50.0 kg + 2.3 kg for each inch over 5 feet
• Women: 45.5 kg + 2.3 kg for each inch over 5 feet

Robinson Formula (1983)

A modification of the Devine formula.

• Men: 52 kg + 1.9 kg per inch over 5 feet
• Women: 49 kg + 1.7 kg per inch over 5 feet

Miller Formula (1983)

Another modification.

• Men: 56.2 kg + 1.41 kg per inch over 5 feet
• Women: 53.1 kg + 1.36 kg per inch over 5 feet

For all formulas, if the height is 5 feet or less, the base weight is used, or the formulas are not typically applied in the same way for very short statures or children.

Variables Used in Predicted Weight Formulas

Variable	Meaning	Unit	Typical Range
Height	Individual’s height	cm or inches	100 – 250 cm
Inches over 5 feet	Height in inches minus 60	inches	0 – 30+
Base Weight	Starting weight at 5 feet tall	kg	45.5 – 56.2 kg
Increment per inch	Additional weight per inch over 5 feet	kg/inch	1.36 – 2.7 kg/inch
Gender	Biological sex, influences base weight and increment	Male/Female	N/A

Practical Examples (Real-World Use Cases)

Example 1: Male, 180 cm

Let’s use the Predicted Weight Calculator for a male who is 180 cm tall.

• Height = 180 cm (approx. 70.87 inches, or 5 feet 10.87 inches)
• Inches over 5 feet = 10.87 inches
• Gender = Male

Using Hamwi: 48.0 kg + 2.7 kg * 10.87 = 48.0 + 29.35 = 77.35 kg (approx. 170.5 lbs)

Using Devine: 50.0 kg + 2.3 kg * 10.87 = 50.0 + 25.00 = 75.00 kg (approx. 165.3 lbs)

The predicted weight ranges around 75-77 kg.

Example 2: Female, 165 cm

Now for a female who is 165 cm tall.

• Height = 165 cm (approx. 64.96 inches, or 5 feet 4.96 inches)
• Inches over 5 feet = 4.96 inches
• Gender = Female

Using Hamwi: 45.5 kg + 2.2 kg * 4.96 = 45.5 + 10.91 = 56.41 kg (approx. 124.4 lbs)

Using Devine: 45.5 kg + 2.3 kg * 4.96 = 45.5 + 11.41 = 56.91 kg (approx. 125.5 lbs)

The predicted weight is around 56-57 kg.

How to Use This Predicted Weight Calculator

1. Enter Height: Input your height in centimeters (cm) into the designated field.
2. Select Gender: Choose your biological gender (Male or Female) from the dropdown menu.
3. View Results: The calculator will automatically display the predicted weight based on the Hamwi formula as the primary result, along with a healthy weight range (typically +/- 10%) and the BMI at that predicted weight.
4. Check the Table: The table below the calculator shows predicted weights using other common formulas (Devine, Robinson, Miller) for comparison.
5. See the Chart: The chart visually represents the Hamwi predicted weight and the +/- 10% healthy range.

The results provide an estimate. Consider it a reference point. If your actual weight is significantly different, or if you have health concerns, consult a healthcare professional. They can provide personalized advice considering your individual body composition, age, activity level, and health status. You can find more information in our Healthy Weight Guide.

Key Factors That Affect Predicted Weight Results

While formulas provide a baseline, many factors influence an individual’s actual ideal or healthy weight:

1. Age: Muscle mass tends to decrease and fat mass increase with age, which can influence ideal weight even if the number on the scale is within a “predicted” range based on height alone. Metabolic rate also changes.
2. Body Frame Size: People have different bone structures (small, medium, large frame). A person with a larger frame may naturally weigh more than someone with a smaller frame, even at the same height.
3. Muscle Mass: Muscle is denser than fat. Individuals with high muscle mass (like athletes) may weigh more than the predicted ideal weight but still be very healthy and lean. A standard Predicted Weight Calculator doesn’t directly account for muscle mass vs. fat mass.
4. Body Fat Percentage and Distribution: Health is more closely linked to body fat percentage and where fat is stored (e.g., abdominal fat is riskier) than to total weight alone. Our Body Fat Calculator can be helpful here.
5. Genetics: Genetic factors can influence metabolism, body shape, and predisposition to weight gain or leanness.
6. Activity Level: Regular physical activity influences muscle mass, metabolism, and overall body composition.
7. Health Conditions: Certain medical conditions (e.g., thyroid issues, hormonal imbalances) and medications can affect weight.
8. Ethnicity: Some studies suggest that ideal weight ranges might vary slightly between different ethnic groups due to differences in body composition and disease risk at certain weights.

Frequently Asked Questions (FAQ)

1. Is the predicted weight the same as my ideal weight?

The “predicted weight” from these formulas is often called “Ideal Body Weight” (IBW), but it’s a theoretical estimate. Your personal ideal weight might vary based on the factors listed above (muscle mass, frame size, age, etc.). It’s a guideline, not a strict rule. Using a BMI Calculator can give another perspective.

2. How accurate are these predicted weight formulas?

They provide a reasonable estimate for average adults but are less accurate for very tall, very short, muscular, or elderly individuals. They don’t account for body composition.

3. What if my weight is very different from the predicted weight?

If you are significantly above or below the predicted range, it’s a good idea to consult a healthcare provider. They can assess your overall health, body composition, and help you determine a healthy weight for you.

4. Can I use the Predicted Weight Calculator for children or adolescents?

No, these formulas are generally designed for adults. Children and adolescents are still growing, and their healthy weight is assessed using growth charts and BMI-for-age percentiles by pediatricians.

5. Do these formulas account for body frame size?

Most simple formulas (like Hamwi, Devine) do not explicitly include frame size. Some practitioners adjust the IBW by +/- 10% to account for small or large frames, but this is an approximation.

6. Which formula used by the Predicted Weight Calculator is the best?

There isn’t one “best” formula. They were developed at different times for different purposes, and all provide slightly different results. They are all estimations. The table shows results from several to give you a range.

7. What is a healthy weight range?

A healthy weight range is often considered to be within +/- 10-15% of the predicted ideal body weight, or corresponding to a BMI between 18.5 and 24.9. However, individual factors are crucial.

8. How does muscle mass affect the predicted weight?

People with high muscle mass may weigh more than the predicted ideal weight but have low body fat and be very healthy. These formulas don’t differentiate between muscle and fat. Consider a fitness goals assessment for more personalized insights.