Welcome to the definitive financial-grade health tool designed to accurately calculate your best possible weight. Using industry-standard medical algorithms, we help you determine your ideal body mass range for optimal health and longevity.
Best Weight Calculator
Male
Female
Biological sex affects lean mass calculations.
Please enter a valid height in feet.
Combine with feet for total height.
Please enter valid inches (0-11).
Used to compare against your ideal range.
Please enter a positive weight.
Best Possible Weight (Average)
166 lbs
Based on the composite of 4 medical formulas
Devine Formula (1974)170 lbs
Robinson Formula (1983)164 lbs
Miller Formula (1983)161 lbs
Healthy BMI Range136 – 184 lbs
Figure 1: Comparison of your current weight against various ideal weight formulas and the healthy BMI ceiling.
Summary Table
Metric
Value
Difference from Current
Table 1: Detailed breakdown of weight targets derived from clinical formulas.
What is "Calculate Your Best Possible Weight"?
When you seek to calculate your best possible weight, you are engaging in a process of determining the Ideal Body Weight (IBW) specifically suited to your height and gender. Unlike generic weight loss goals, this calculation relies on medically validated formulas derived from pharmacological data and population health statistics. It is a critical metric for establishing realistic health objectives, calculating drug dosages in clinical settings, and monitoring nutritional status.
This tool is designed for adults who want to move beyond simple scale readings and understand the physiological baseline for their body type. A common misconception is that there is a single "perfect" weight. In reality, when you calculate your best possible weight, you obtain a range of values based on different medical perspectives, such as the Devine or Robinson formulas, each prioritizing different physiological factors.
Best Weight Formulas and Mathematical Explanation
To accurately calculate your best possible weight, we employ four distinct mathematical models. These formulas assume a base weight for a height of 5 feet and add weight for every inch over 5 feet.
The Core Formulas (Calculated in kg, converted to lbs)
1. Devine Formula (1974): Originally developed for computing drug clearances. It is the most widely used standard.
Male: 50kg + 2.3kg per inch over 5ft
Female: 45.5kg + 2.3kg per inch over 5ft
2. Robinson Formula (1983): A refinement of the Devine formula based on updated actuarial data.
Male: 52kg + 1.9kg per inch over 5ft
Female: 49kg + 1.7kg per inch over 5ft
Variables Table
Variable
Meaning
Unit
Typical Range
Base Weight
Starting weight for 5ft height
kg / lbs
45-56 kg
Height Factor
Weight added per inch
kg/inch
1.4 – 2.7 kg
Gender
Biological sex modifier
Binary
Male / Female
Table 2: Key variables used to calculate your best possible weight.
Practical Examples (Real-World Use Cases)
Example 1: The Average Male
John is a 5'10" (70 inches) male who wants to calculate your best possible weight to set a gym goal.
Input: Male, 5 feet, 10 inches.
Calculation (Devine): 50kg + (2.3 * 10) = 73kg (~161 lbs).
Calculation (Robinson): 52kg + (1.9 * 10) = 71kg (~156.5 lbs).
Interpretation: John's "best" weight is likely between 156 and 161 lbs. If he weighs 200 lbs, he has a clear target for reduction.
Example 2: The Tall Female
Sarah is 5'8″ (68 inches) and checks the tool.
Input: Female, 5 feet, 8 inches.
Calculation (Miller): 53.1kg + (1.36 * 8) = ~64kg (~141 lbs).
Calculation (BMI Range): For 5'8″, the healthy BMI range (18.5-24.9) suggests a weight between 122 lbs and 164 lbs.
Interpretation: While the strict formula suggests 141 lbs, the BMI calculations show she is healthy up to 164 lbs. This helps Sarah avoid unrealistic pressure to be too thin.
How to Use This Best Weight Calculator
Enter Gender: Select biological sex as formulas differentiate bone mass and muscle density distributions.
Input Height: accurately enter feet and inches. Even one inch can shift the result by 3-5 lbs.
Enter Current Weight: This allows the tool to calculate the variance between your current status and your ideal goal.
Analyze Results: Review the "Main Result" which is an average. Then check the breakdown. If you are muscular, lean towards the higher values (Devine). If you have a smaller frame, look at Miller.
Use the Copy Feature: Click "Copy Results" to save the data for your medical records or fitness tracker.
Key Factors That Affect Best Weight Results
When you calculate your best possible weight, the number is a baseline. Several real-world factors influence where you should actually be:
Muscle Mass: Muscle is denser than fat. An athlete may weigh significantly more than their "formula" weight but be healthier.
Bone Frame Size: Wrist circumference correlates with frame size. Larger frames can carry 10% more weight healthily.
Age: As metabolism slows and muscle density changes with age, maintaining the strict "ideal" of a 20-year-old may not be optimal for seniors.
Body Composition: Two people can calculate your best possible weight and get the same number, but one may have 10% body fat and the other 30%. Composition matters more than the raw number.
Fluid Retention: Daily weight fluctuates by 1-4 lbs due to sodium intake and hydration, affecting your daily comparison to the ideal.
Health History: Individuals recovering from illness may need higher reserves. Consult a medical professional for personalized advice.
Frequently Asked Questions (FAQ)
1. Why do different formulas give different results?
Each formula (Devine, Robinson, Miller) was created using different population datasets and for different purposes (e.g., pharmacology vs. insurance actuarial tables). To calculate your best possible weight accurately, we average them to smooth out biases.
2. Does this calculator apply to children?
No. These formulas are strictly for adults (18+). Children require specialized growth charts.
3. I am a bodybuilder, is this accurate?
Likely not. These formulas do not account for high muscle mass. Use a Body Fat Calculator instead.
4. What if I am under 5 feet tall?
The standard formulas (Base 5ft) become less accurate. We extrapolate downwards, but clinical judgment is advised.
5. Is the "Best Possible Weight" the same as "Healthy Weight"?
Not always. "Best" often refers to a statistical ideal, whereas "Healthy" (BMI 18.5-24.9) is a broader range where disease risk is minimized.
6. How often should I calculate this?
Your ideal weight based on height doesn't change as an adult. However, you should check your progress against this target monthly.
7. Should I use this for insurance exams?
Insurance companies often use the Robinson or similar actuarial tables. Knowing this number helps you prepare.
8. Can I change the units to Metric?
Currently, this tool uses standard US Imperial units (Lbs/Ft/In) as they are the standard for the original Devine formulas, but you can convert the final result to kg by dividing by 2.204.
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