Ideal Weight Calculator
Enter your age, gender and height to estimate your ideal body weight using four established medical formulas plus a healthy BMI based range.
Your Ideal Weight Result
| Formula | Ideal Weight |
|---|
Ideal Weight Calculator
Not sure of the best weight for your body? Our ideal weight calculator is absolutely free; we use four of the most popular medical formulas for calculating the range of healthy weight, plus the healthy BMI range from the World Health Organization for your ideal weight range. Just put in your height, age and gender to see an instant side-by-side comparison.
What is Ideal Body Weight (IBW)?
The ideal body weight is an approximation calculated by physicians to determine a proper dosage of drugs for a person, and not to determine an aesthetic standard.
IBW formulas have also been applied in sports classification, nutrition planning and in general health screening over a period of time.
It should be noted that there is no single formula which explains everything. IBW is based only on height and sex and does not take into account muscle mass, bone density, or percentage of body fat.
A muscular athlete can be at the extremes of the paper range of health and yet be perfectly healthy. These are guidelines for discussion with your doctor and not goals to set.
How to Use This Calculator
- Select your unit system (US, metric, or other).
- Enter your age (valid for ages 2 to 80).
- Choose your gender.
- Enter your height.
- Click Calculate to see your ideal weight across all four formulas plus the healthy BMI range.
The Formulas Behind the Calculator
Each formula provides a standard weight for a 5′ frame, and then a fixed weight amount for each inch over.
They vary slightly as each was derived from a different clinical research, but their purposes are all to estimate a clinically reasonable body weight.
Hamwi Formula (1964)
- Male: 48.0 kg + 2.7 kg per inch over 5 feet
- Female: 45.5 kg + 2.2 kg per inch over 5 feet
Developed by Dr. G. J. Hamwi to help clinicians estimate medication dosages quickly at the bedside.
Devine Formula (1974)
- Male: 50.0 kg + 2.3 kg per inch over 5 feet
- Female: 45.5 kg + 2.3 kg per inch over 5 feet
Created by Dr. B. J. Devine, this remains the most commonly cited IBW formula in clinical and pharmaceutical settings today.
Robinson Formula (1983)
- Male: 52 kg + 1.9 kg per inch over 5 feet
- Female: 49 kg + 1.7 kg per inch over 5 feet
A refinement of the Devine formula based on updated population data.
Miller Formula (1983)
- Male: 56.2 kg + 1.41 kg per inch over 5 feet
- Female: 53.1 kg + 1.36 kg per inch over 5 feet
Another Devine-based adjustment, generally producing the highest weight estimates of the four.
Healthy BMI Range
For adults of both sexes a healthy BMI is defined as 18.5 to 25. The BMI is just height and weight so our calculator works backwards to calculate a healthy weight range for your height; thus, a wide range is provided in addition to the 4 listed formulas.
What Affects Your Ideal Weight?
Age: Height and ideal weight are fairly stable through adulthood, though most adults gradually lose some height after age 40, and lean muscle naturally declines with age unless offset by regular strength training.
Gender: Men typically carry more muscle mass and higher bone density than women, which is why male ideal weight estimates run higher than female estimates at the same height.
Height: Taller individuals carry proportionally more muscle and body fat, so ideal weight increases steadily with height in every formula.
Body Frame Size: Wrist circumference relative to height is commonly used to classify someone as small, medium, or large boned. A larger frame size naturally corresponds to a higher healthy weight, even at identical height.
Limitations to Keep in Mind
These formulas were created with general clinical applications in mind, and not for specific precision. They do not take into account activity level, muscle to fat ratio, pregnancy or existing health condition.
In any case, the formulas are designed for the average population, if you are an athlete, body builder or anything that is not in the average population you should take the result as a reference and not as a goal.
Use this tool in addition to a BMI calculator or a health care professional to get a more comprehensive view of health.
Frequently Asked Questions
Q1: Which ideal weight formula is the most accurate?
Ans: There is no single “most accurate” formula as each was created based on different sets of participants.
All four formulas are used in clinical practice with the Devine being the most popular, so using all four combined with the healthy BMI range will give a more rounded picture than using just one.
Q2: Is ideal body weight the same as a healthy weight?
Ans: Not exactly. While IBW is a formula-based estimation, and is used to dose medication.
A healthy weight is dependent upon factors such as body composition, activity level, and health markers which are not captured in any formula.
Q3: Can I use this calculator if I’m under 18?
Ans: This calculator is intended for use by adults. The CDC provides age and gender-specific BMI percentile charts which are a more appropriate way of assessing healthy weight for children and teens than the use of adult IBW formulas.
Q4: Why do the four formulas give me different results?
Ans: The multipliers of each formula were derived decades apart from different research populations, and there are slight differences between the formulas.
Looking at the entire range, not just one number, provides a more realistic range.
Q5: Does muscle mass affect my ideal weight result?
Ans: Yes, indirectly. The formulas only take height and gender into account and athletes or people with above average muscle mass might end up with a weight that is lower than what they may be in a healthy state.
Body composition measurements such as a body fat calculator can provide context.