Professional Calculator using Devine, Robinson, and Miller Formulas
Male
Female
Biological sex affects bone mass and lean tissue calculations.
Please enter a valid height in feet.
Inches must be between 0 and 11.
Used to compare against the ideal range.
Please enter a valid positive weight.
Estimated Ideal Weight (Devine Formula)165.2 lbs
Healthy BMI Range (18.5-24.9)129 – 174 lbs
Robinson Formula162.5 lbs
Miller Formula160.8 lbs
The Devine Formula is widely used medically for dosage calculations and is the standard for "Ideal Body Weight" (IBW).
Analysis Visualization
Chart Comparison: Your current weight vs. calculated ideal weight formulas and the healthy BMI ceiling.
Formula Comparison Table
Method
Calculated Weight (lbs)
Calculated Weight (kg)
Comparison of standard medical formulas for estimating ideal body weight based on height and gender.
What is "How to Calculate My Ideal Weight"?
When people ask "how to calculate my ideal weight," they are typically looking for a standardized metric known as Ideal Body Weight (IBW). This is a calculation derived from formulas originally developed for medical dosing but now widely used in health and fitness to establish weight goals.
Unlike Body Mass Index (BMI), which is a broad range based on height and weight, IBW formulas provide a specific target number. These calculations are most useful for individuals establishing long-term fitness goals, athletes monitoring performance weight, and medical professionals determining dosage requirements. However, a common misconception is that there is only one "perfect" weight. In reality, ideal weight varies based on frame size, muscle mass, and age.
Ideal Body Weight Formula and Mathematical Explanation
To understand how to calculate my ideal weight, we must look at the mathematical models. The most common formula is the Devine Formula (1974). It was originally designed to calculate gentamicin clearance but has become the industry standard.
Devine Formula (Men): 50kg + 2.3kg × (Height in inches – 60) Devine Formula (Women): 45.5kg + 2.3kg × (Height in inches – 60)
Below is a table defining the variables used in these calculations:
Variable
Meaning
Unit
Typical Range
Base Weight
Starting weight constant for 5ft height
kg
50 (M) / 45.5 (F)
Height Factor
Weight added per inch over 5ft
kg/inch
2.3 (Devine)
Height Offset
Inches exceeding 60 (5ft)
inches
0 – 24+
Variables used in the Devine IBW formula.
Practical Examples (Real-World Use Cases)
Example 1: Male, 5ft 10in
Scenario: John wants to know his ideal weight for a marathon training program.
Input Height: 70 inches (5ft + 10in)
Base Calculation: Height over 5ft is 10 inches.
Math: 50kg + (2.3kg × 10) = 50 + 23 = 73kg.
Conversion: 73kg × 2.204 = 160.9 lbs.
Interpretation: According to the Devine formula, John's target medical weight is approximately 161 lbs.
Example 2: Female, 5ft 4in
Scenario: Sarah is setting a weight loss goal and wants a realistic target.
Input Height: 64 inches
Base Calculation: Height over 5ft is 4 inches.
Math: 45.5kg + (2.3kg × 4) = 45.5 + 9.2 = 54.7kg.
Conversion: 54.7kg × 2.204 = 120.6 lbs.
Interpretation: Sarah's calculated ideal weight is roughly 121 lbs, though a healthy BMI range allows for fluctuation above this.
How to Use This Ideal Weight Calculator
Follow these steps to get the most accurate results:
Select Gender: Choose biological sex, as formulas differ significantly between men and women due to average lean body mass differences.
Enter Height: Input your height in feet and inches accurately. Even one inch can shift the ideal weight by over 5 lbs.
Enter Current Weight: This is optional for the IBW calculation itself but is required to see how far you are from the target and to visualize the gap in the chart.
Review the Primary Result: The large highlighted number uses the Devine formula.
Check the Range: Look at the "Healthy BMI Range" to see the floor and ceiling of what is medically considered healthy.
Key Factors That Affect Ideal Weight Results
When asking "how to calculate my ideal weight," the formula is only a starting point. Several real-world factors influence what your true ideal weight should be:
Muscle Mass: Muscle is denser than fat. An athlete may weigh significantly more than their formulaic IBW but actually be healthier due to low body fat percentage.
Frame Size: People with larger bone structures (wrist circumference > 7 inches for men) should generally add 10% to the IBW result, while small frames subtract 10%.
Age: As we age, bone density changes and metabolism slows. Some research suggests slightly higher weights in older age are protective against frailty.
Pregnancy & Nursing: Standard IBW formulas do not account for the weight of a fetus, placenta, or increased blood volume.
Fluid Retention: Daily weight can fluctuate by 2-5 lbs due to sodium intake and hydration, which formulas cannot predict.
Health Conditions: Certain conditions like osteoporosis (lighter bones) or edema (excess fluid) will skew the applicability of standard weight charts.
Frequently Asked Questions (FAQ)
Is the calculated ideal weight a strict rule?
No. It is a statistical estimate. Your "healthy" weight depends on body composition. If you have high muscle mass, you may weigh more than the calculation suggests and still be very healthy.
Which formula is the most accurate?
The Devine formula (1974) is the most widely used in medical settings. The Robinson formula (1983) is also highly respected. Our calculator displays multiple options so you can see the consensus range.
Does this calculator apply to children?
No. Children and teenagers are still growing, and their weight goals should be determined using CDC growth charts (percentiles), not adult IBW formulas.
How does frame size affect the calculation?
Standard formulas assume a medium frame. If you have a large frame, your ideal weight might be 10% higher than the result shown. If you have a small frame, it might be 10% lower.
What if my goal weight is different from the result?
That is fine. The calculation provides a medical baseline. Aesthetic goals or specific athletic class requirements often differ from the pure medical IBW.
Why is there a difference between men and women?
Men typically have higher bone density and muscle mass than women of the same height, leading to a higher baseline weight in the calculation formulas.
Can I use this for weight loss planning?
Yes. Calculating your ideal weight gives you a concrete target. You can then use this to calculate your required Calorie Deficit to reach that goal safely.
Does the calculator account for fat percentage?
No, IBW formulas are based strictly on height and gender. To understand body composition, you would need a body fat caliper test or DEXA scan.