Determine your ideal body weight using age-adjusted formulas and medical standards.
Used for Creff Formula adjustments.
Please enter a valid age (15-100).
Please enter a valid height.
Please enter a valid height.
Small / Slim
Medium / Normal
Large / Broad
Affects Creff Formula calculation.
Age-Adjusted Ideal Weight (Creff)
70.5kg
Based on Creff Formula considering age & frame.
Devine Formula (Medical Std)
70.0 kg
Healthy BMI Range
56.7 – 76.6 kg
Robinson Formula
68.5 kg
Method
Calculated Weight
Considerations
What is "How to Calculate My Weight with Age and Height"?
When people ask how to calculate my weight with age and height, they are typically looking for a way to determine their Ideal Body Weight (IBW). Unlike a simple scale reading, calculating your ideal weight involves mathematical formulas that have been developed by medical professionals over decades to estimate a healthy weight target based on your specific skeletal structure and demographics.
While the Body Mass Index (BMI) is the most common tool, it is a general indicator. More specific formulas, such as the Creff Formula, explicitly incorporate age and body frame size into the equation, providing a more personalized answer to the question of how much you should weigh.
Who should use this calculation? This tool is ideal for adults looking to set realistic health goals, fitness enthusiasts tracking progress, and anyone wanting a more nuanced understanding of their weight beyond simple BMI charts.
Formulas and Mathematical Explanation
To accurately answer "how to calculate my weight with age and height," we utilize several distinct mathematical models. Each serves a slightly different purpose.
1. The Creff Formula (Age-Adjusted)
This is the primary formula for this specific topic because it is one of the few that directly includes age as a variable. It acknowledges that metabolism and body composition change over time.
Formula (Metric): Ideal Weight = [(Height in cm - 100) + (Age / 10)] × 0.9 × Frame Correction
Frame Correction: 0.9 for small frame, 1.0 for medium, 1.1 for large.
2. The Devine Formula (1974)
The medical standard often used for dosing medications. It relies heavily on height and gender.
Male: 50 kg + 2.3 kg per inch over 5 feet
Female: 45.5 kg + 2.3 kg per inch over 5 feet
Variables Table
Variable
Meaning
Typical Unit
Height
Vertical stature
cm or inches
Age
Years lived (affects Creff formula)
Years
Frame Size
Wrist circumference/skeletal width
Small/Med/Large
Practical Examples
Example 1: The Aging Metabolism
Scenario: John is a 50-year-old male, 180 cm (5'11") tall with a medium frame.
Devine Formula (Height only): Calculates approximately 75 kg (165 lbs).
Creff Formula (With Age): [(180 – 100) + (50 / 10)] × 0.9 × 1.0 = 76.5 kg (168.6 lbs).
Interpretation: The age-adjusted formula allows for a slightly higher weight, acknowledging natural physiological changes that occur with age.
Example 2: Petite Frame Consideration
Scenario: Sarah is a 30-year-old female, 160 cm (5'3″) tall with a small frame.
Standard BMI Midpoint: Might suggest around 55 kg.
Analyze Results: Look at the "Age-Adjusted Ideal Weight" for a personalized target, but also review the "Healthy BMI Range" for a broader safe zone.
Key Factors That Affect Your Results
When learning how to calculate my weight with age and height, consider these six factors that formulas might simplify:
Muscle Mass: Muscle is denser than fat. An athlete may weigh more than their "ideal" weight but be perfectly healthy.
Bone Density: While "frame size" approximates this, actual bone density varies significantly and affects scale weight.
Age-Related Muscle Loss (Sarcopenia): As we age, we naturally lose muscle. Maintaining weight while losing muscle means gaining fat, which is why monitoring body composition is as important as weight.
Hydration Levels: Daily weight can fluctuate by 1-2% based on water retention, salt intake, and hydration.
Fat Distribution: Visceral fat (around organs) is more dangerous than subcutaneous fat. Two people with the same weight and height may have different health risks based on where fat is stored.
Hormonal Changes: Particularly for women during menopause, hormonal shifts can alter where weight is stored and how difficult it is to lose, influencing what is a "sustainable" ideal weight.
Frequently Asked Questions (FAQ)
Does age really change my ideal weight?
Yes and no. Medically, a healthy BMI range remains largely consistent for adults. However, practically, maintaining the exact same weight at 60 as at 20 is difficult due to metabolic slowing. The Creff formula accounts for this by allowing a slight increase with age.
Why do different formulas give different results?
Formulas like Devine, Robinson, and Miller were developed using different population data sets. Devine is often used for medication dosing, while BMI is used for general health screening. Using an average of these gives the most balanced view.
Is this calculator accurate for children?
No. Children and teenagers require specialized growth charts (CDC or WHO percentiles) because they are still developing. This tool is for adults (18+).
How do I know my frame size?
Wrap your thumb and middle finger around your opposite wrist. If they overlap, you likely have a small frame. If they touch, medium. If they don't meet, large.
Should I aim for the exact number?
No. Treat the result as a target range (±5-10%). Your weight fluctuates daily, and aiming for a single number can lead to unhealthy obsession.
Does this calculator measure body fat?
No. It calculates weight based on height and age. To measure body fat percentage, you need calipers, a DEXA scan, or bioimpedance scales.
What if I am very muscular?
If you are a bodybuilder or athlete, these formulas will likely underestimate your ideal weight. In your case, body fat percentage is a better metric than weight.
Is a lower weight always better?
No. Being underweight carries risks like osteoporosis, weakened immunity, and anemia. Stay within the "Healthy BMI Range" provided in the results.
Related Tools and Resources
BMI Calculator – Calculate your Body Mass Index specifically.