Use this professional calculator to determine your ideal body weight based on clinically validated formulas (Devine, Robinson, Miller) and BMI ranges.
Male
Female
Biological sex affects body composition formulas.
Enter height in centimeters.
Please enter a valid height (50-300 cm).
Enter height in feet and inches.
Please enter valid height values.
Estimated Ideal Weight (Devine Formula)
70.0 kg
Healthy BMI Range
56.7 – 76.6 kg
Robinson Formula
68.5 kg
Miller Formula
67.2 kg
Formula Used: The primary result uses the Devine (1974) formula, widely used for medical dosages.
Male Ideal Weight = 50 kg + 2.3 kg per inch over 5 feet.
Comparison of Ideal Weight Formulas vs. BMI Healthy Limit
Reference: Ideal Weight Formulas by Height
Formula
Calculation Logic
Typical Application
Devine
Base + Increment per inch > 5ft
Medical Dosing (Standard)
Robinson
Revised Devine metrics
Population Statistics
Miller
Correction for height/weight
Anthropometric Research
Table 1: Comparison of major ideal weight calculation methodologies.
What is "How to Calculate the Ideal Weight"?
Learning how to calculate the ideal weight is a fundamental step in assessing long-term health, nutritional needs, and fitness goals. "Ideal weight" does not refer to a single perfect number but rather a healthy range or a calculated target based on population averages. Medical professionals use these calculations to determine drug dosages, assess obesity risks, and set milestones for weight management programs.
Anyone concerned about cardiovascular health, diabetes prevention, or athletic performance should understand these metrics. While aesthetic goals vary, medical ideal weight focuses on minimizing health risks. A common misconception is that one formula fits all; in reality, different formulas (Devine, Robinson, Miller) offer slight variations based on how they weigh height and gender.
Ideal Weight Formulas and Mathematical Explanation
To understand how to calculate the ideal weight mathematically, we look at the most accepted equation: the Devine Formula (1974). Originally designed for calculating medication dosages like gentamicin, it has become the standard for weight assessment.
The Devine Formula (Metric):
Men: 50 kg + 2.3 kg × (Height in inches – 60)
Women: 45.5 kg + 2.3 kg × (Height in inches – 60)
Variables Breakdown:
Variable
Meaning
Unit
Typical Range
Base Weight
Starting weight for 5ft height
kg
50 (M) / 45.5 (F)
Increment
Weight added per unit of height
kg/inch
2.3
Height Threshold
Height at which increment begins
inches
60 (5 feet)
Table 2: Variables used in the Devine Ideal Weight Formula.
Practical Examples (Real-World Use Cases)
Example 1: The Average Male
Consider a male who is 5 feet 10 inches tall (178 cm). He wants to know how to calculate the ideal weight to set a gym target.
Height over 5ft: 10 inches.
Calculation: 50 kg + (2.3 kg × 10) = 50 + 23 = 73 kg.
Result: His ideal weight is approximately 73 kg (161 lbs).
Financial/Health Impact: Maintaining this weight may reduce insurance premiums related to BMI risk factors.
Example 2: The Petite Female
A female client is 5 feet 4 inches tall (163 cm).
Height over 5ft: 4 inches.
Calculation: 45.5 kg + (2.3 kg × 4) = 45.5 + 9.2 = 54.7 kg.
Result: Her ideal weight is approximately 54.7 kg (120.5 lbs).
Interpretation: This provides a baseline. If her actual weight is 65kg, she might aim for a sustainable reduction towards this figure, though muscle mass must be considered.
How to Use This Ideal Weight Calculator
Select Unit System: Choose between Metric (kilograms/centimeters) or Imperial (pounds/feet/inches) using the toggle at the top.
Input Gender: Select Male or Female. This adjusts the base weight in the formula (50kg vs 45.5kg).
Enter Height: Input your accurate height. For Imperial, ensure you split feet and inches correctly (e.g., 5 ft, 10 in).
Review Primary Result: The large highlighted number represents the Devine formula result, the industry standard.
Analyze Intermediate Values: Check the "Healthy BMI Range" to see the broader spectrum of medically healthy weights, and compare with Robinson/Miller formulas for perspective.
Copy Results: Use the "Copy Results" button to save the data for your health records or consultation notes.
Key Factors That Affect Ideal Weight Results
When studying how to calculate the ideal weight, simple math implies a rigid number, but biological and financial realities introduce variables:
Muscle Mass vs. Fat: Muscle is denser than fat. An athlete may weigh significantly more than the "ideal" formula result yet be healthier and have lower financial health risks than a sedentary person at the "ideal" weight.
Frame Size: Bone structure varies. A person with a large frame (wrist circumference > 7.5″) may naturally carry 10% more weight than the formula suggests without health detriment.
Age: Metabolism slows and body composition changes with age. Older adults often carry slightly more weight to provide nutritional reserves during illness, a factor not captured by simple linear equations.
Health Insurance Premiums: While not a biological factor, BMI and weight classes often dictate life insurance rates. Being within the "Ideal" range often correlates with "Preferred" pricing tiers.
Hydration Levels: Daily weight fluctuation due to water retention can vary by 1-3 kg, making single-point measurements less reliable than trends.
Bone Density: High bone mineral density increases total scale weight but is a positive indicator of longevity and structural health, contradicting the goal of simply "weighing less."
Frequently Asked Questions (FAQ)
1. Is the Devine formula the only way how to calculate the ideal weight?
No. While Devine is the medical standard, the Robinson, Miller, and Hamwi formulas are also valid. BMI provides a range rather than a specific target number.
2. Does this calculator apply to children?
No. Children and adolescents require specialized growth charts (CDC or WHO percentiles) because their height-weight ratio changes rapidly during development.
3. Why is the female ideal weight lower than the male?
Biologically, men generally have higher muscle mass and bone density. The formulas account for this by starting with a lower base weight for females (45.5kg vs 50kg).
4. Can I be healthy if I am above my ideal weight?
Absolutely. If the excess weight is muscle mass (e.g., bodybuilders), you may be metabolically healthy. The calculator provides a baseline, not a diagnosis.
5. How often should I recalculate my ideal weight?
Your ideal weight target based on height rarely changes after age 20. However, you should reassess your actual weight relative to this target weekly.
6. What if my height is under 5 feet?
The standard formulas often break down under 5 feet. In these cases, 2-5 lbs is often subtracted per inch under 5 feet, though BMI ranges become a more reliable metric.
7. How does frame size impact the calculation?
Standard formulas assume a medium frame. Small-framed individuals should subtract 10%, and large-framed individuals should add 10% to the final result.
8. Does ideal weight affect life insurance costs?
Yes. Insurers use height/weight tables. Being significantly over or under the ideal range can trigger higher premiums or require additional medical exams.
Related Tools and Internal Resources
Explore our other financial and health planning tools to optimize your lifestyle:
BMI Calculator » Calculate your Body Mass Index to assess general health categories.
BMR Calculator » Determine your Basal Metabolic Rate to understand daily calorie needs.