Determine your medically ideal body weight range using professional algorithms.
Professional Ideal Weight Calculator
Male
Female
Biological sex affects bone mass and muscle distribution assumptions.
Standard formulas apply best to adults aged 18+.
Please enter a valid age between 18 and 120.
Please enter a reasonable height.
Inches must be between 0 and 11.
Small Frame (-10%)
Medium Frame (Average)
Large Frame (+10%)
Adjusts calculation for bone density and structure.
Estimated Ideal Weight160 lbsBased on Modified Devine Formula
Healthy BMI Range (18.5-25)125 – 169 lbs
Robinson Formula158 lbs
Miller Formula155 lbs
Note: This calculation determines weight according to height and age based on peer-reviewed medical formulas.
Formula Breakdown
Method
Calculation Result (lbs)
Standard Deviation
Ideal Weight Comparison
Comparison of major medical formulas (Robinson, Miller, Devine, Hamwi)
What is Calculate Weight According to Height and Age?
The process to calculate weight according to height and age involves using mathematical formulas derived from actuarial data and medical studies to determine an "Ideal Body Weight" (IBW). Unlike a simple scale reading, this calculation provides a target weight range that typically correlates with the lowest risk of mortality and chronic diseases such as hypertension, diabetes, and cardiovascular issues.
Health professionals, dietitians, and insurers use these figures to assess health risks. However, a common misconception is that there is a single "perfect" weight. In reality, a healthy weight is a range that accounts for gender, muscle mass, and bone structure (frame size).
While age is a factor, most clinical formulas prioritize height and gender. However, modern interpretations often adjust expectations for age, acknowledging that a slightly higher weight in older adults (aged 65+) may provide protective health benefits.
IBW Formulas and Mathematical Explanation
To calculate weight according to height and age, several established equations are used. The most common is the Devine Formula (1974), originally developed for drug dosing but now standard for weight estimation.
The Devine Formula
Men: 50 kg + 2.3 kg per inch over 5 feet
Women: 45.5 kg + 2.3 kg per inch over 5 feet
Variables Table
Variable
Meaning
Unit
Typical Range
H
Height
Inches / cm
58″ – 80″
Base
Base Weight Constant
kg
45.5 (F) – 50 (M)
Frame
Body Frame Adjustment
%
-10% to +10%
Practical Examples (Real-World Use Cases)
Example 1: The 30-Year-Old Male
John is a 30-year-old male, 5 feet 10 inches tall with a medium frame. He wants to know his ideal weight target for marathon training.
Input: Male, 5'10" (70 inches), Medium Frame
Math: Base 50kg + (2.3kg × 10 inches) = 73kg
Conversion: 73kg ≈ 161 lbs
Result: John's ideal weight is approximately 161 lbs. A healthy BMI range would place him between 129 and 174 lbs.
Example 2: The 55-Year-Old Female
Susan is 55, 5 feet 4 inches tall, and has a small body frame. She wants to calculate weight according to height and age to set a diet goal.
Frame Adjustment: Small frame reduces this by 10%. 120 lbs – 12 lbs = 108 lbs.
Result: Susan's frame-adjusted ideal weight is roughly 108 lbs. Without the frame adjustment, it would be 120 lbs.
How to Use This Calculator
Select Gender: Choose Male or Female. This sets the base constant for the formula.
Enter Age: While standard formulas focus on height, entering your age ensures you aren't using this tool for children (under 18), for whom standard growth charts are required.
Input Height: Enter your height in Feet and Inches accurately. This is the most critical variable.
Select Frame Size: If you have small wrists/ankles compared to average, select "Small". If you have broad shoulders/hips, select "Large". This adjusts the result by 10%.
Review Results: The primary result shows the Devine average. The table below compares other formulas like Robinson and Miller to give you a broader perspective.
Key Factors That Affect Weight Calculation Results
When you calculate weight according to height and age, several physiological factors influence the "true" ideal number:
Muscle Mass vs. Fat: Muscle is denser than fat. An athlete may weigh more than the calculator suggests but still be healthy (low body fat percentage).
Bone Density: Frame size inputs attempt to correct for this, but individual variations in bone mineral density can affect scale weight by 5-10 lbs.
Age-Related Shifts: Metabolism slows with age. While the "ideal" math remains constant, maintaining that weight becomes harder. Additionally, strictly low weights in elderly populations can sometimes pose frailty risks.
Hydration Levels: Daily weight can fluctuate by 2-4 lbs based on water retention, salt intake, and hydration status.
Distribution of Weight: Visceral fat (belly fat) is more dangerous than subcutaneous fat. Two people may have the same height/weight but different health risks based on where the weight is stored.
Health History: Previous conditions or medications can alter what is achievable or healthy for an individual, overriding generic formulas.
Frequently Asked Questions (FAQ)
Does age affect the ideal weight calculation?
Technically, the classic medical formulas (Devine, Hamwi) rely solely on height and gender. However, age is important for context. As metabolism slows, maintaining the exact weight from your 20s becomes difficult, and BMI charts for seniors often allow for a slightly higher range to support bone health and recovery reserves.
Which formula is the most accurate?
The Devine formula is the most widely used in medical settings for dosing and general estimation. The Robinson and Miller formulas are modifications derived later to improve accuracy for specific populations. We display all major ones so you can see the consensus range.
Why is the result different from my BMI?
BMI (Body Mass Index) is a broad screening tool that calculates a range (e.g., 18.5 to 25). Ideal Weight formulas calculate a specific "point" target. The result from this calculator usually falls right in the middle of your healthy BMI range.
How do I know my frame size?
A simple method is the wrist wrap test. Grip your wrist with your thumb and middle finger of the other hand. If they overlap, you have a small frame. If they touch, medium. If they don't meet, large.
Is this calculator suitable for children?
No. Children and teenagers are still growing, and their weight assessment requires CDC Growth Charts (percentiles) rather than static adult formulas.
Should I diet to reach this exact number?
Not necessarily. These numbers are statistical averages, not mandates. If you are healthy, active, and within a few pounds of the estimate, drastic dieting is rarely recommended. Consult a doctor before starting weight loss programs.
Does this apply to bodybuilders?
No. High muscle mass will skew results. Bodybuilders will often appear "overweight" or "obese" on these charts despite having very low body fat. Body fat percentage is a better metric for athletes.
How often should I check my weight?
Weekly weigh-ins are generally sufficient to track trends without becoming obsessive over daily fluctuations caused by water weight or digestion.