Ideal Weight Calculator
Estimate your ideal body weight using the Devine, Robinson, Miller, and Hamwi formulas. See your healthy BMI range, current weight comparison, and personalised target.
Used to show how far you are from your ideal weight
What Is an Ideal Weight Calculator?
An ideal weight calculator estimates the weight considered healthy or optimal for a person based on their height and sex. It uses established medical formulas — not arbitrary numbers — to produce a reference range that clinicians have used for decades to guide nutrition, medication dosing, and health assessments.
Keep in mind that "ideal weight" is a statistical estimate. Factors like muscle mass, bone density, ethnicity, and individual body composition are not captured by height-based formulas. Use this tool as a guide, not a medical prescription.
How Ideal Weight Is Calculated
All four formulas in this calculator are based on height above 5 feet (60 inches), with a gender-specific base weight in kilograms. Each formula was derived from a different population study and uses slightly different constants.
| Formula | Male | Female | Year |
|---|---|---|---|
| Devine | 50 + 2.3 × (in > 60) | 45.5 + 2.3 × (in > 60) | 1974 |
| Robinson | 52 + 1.9 × (in > 60) | 49 + 1.7 × (in > 60) | 1983 |
| Miller | 56.2 + 1.41 × (in > 60) | 53.1 + 1.36 × (in > 60) | 1983 |
| Hamwi | 48 + 2.7 × (in > 60) | 45.5 + 2.2 × (in > 60) | 1964 |
"in > 60" = height in inches above 60 (i.e. above 5 feet). All results in kg.
Devine vs Robinson vs Hamwi — What's the Difference?
Devine (1974)
The most widely used formula in clinical practice, particularly for calculating ideal body weight for medication dosing. Tends to overestimate for very tall individuals.
Robinson (1983)
A revision of Devine with lower incremental constants. Generally produces slightly lower estimates, particularly for taller individuals.
Miller (1983)
Uses the highest base weight but lowest per-inch increment. Tends to produce results between Robinson and Hamwi. Considered appropriate for lighter-framed people.
Hamwi (1964)
The oldest formula. Originally developed for diabetic patients. Uses the highest per-inch increment for males, making it produce higher estimates for tall men.
Because each formula produces a slightly different result, this calculator shows all four and highlights the average as the recommended estimate. The average smooths out the individual biases of each formula.
Healthy BMI Weight Range Explained
In addition to formula-based ideal weights, this calculator shows your healthy BMI weight range — the weight range that corresponds to a Body Mass Index (BMI) between 18.5 and 24.9.
Min healthy weight = 18.5 × height(m)²
Max healthy weight = 24.9 × height(m)²
The BMI range is broader than any single formula estimate and is widely endorsed by organisations including the WHO and CDC as a population-level screening tool. However, BMI does not distinguish between fat mass and muscle mass — athletes and muscular individuals may show BMI values outside the "healthy" range despite excellent health.
Is Ideal Weight the Same for Everyone?
No. "Ideal weight" is a statistical reference, not a universal target. Several factors influence what a healthy weight looks like for a specific individual:
- •Muscle mass: Muscular individuals weigh more at the same height than average. Formula-based ideal weights can underestimate appropriate weight for athletes.
- •Bone density: People with denser, heavier bones naturally weigh more. This is especially relevant for older adults, where bone density can vary significantly.
- •Age: Older adults typically have lower muscle mass. Some guidelines suggest slightly higher BMI targets (22–27) for people over 65.
- •Ethnicity: Research shows that different ethnic groups may have different health risks at the same BMI. South Asian populations, for example, may have higher metabolic risk at lower BMIs.
- •Body fat distribution: Where fat is stored matters as much as total weight. Central (abdominal) fat carries higher cardiovascular risk than fat distributed elsewhere.
Example Calculations
Input
Male, 175 cm
Recommended
70.5 kg
Healthy Range
56.7–76.3 kg
Formula Avg
68.8 kg
Input
Female, 165 cm
Recommended
58.9 kg
Healthy Range
50.4–67.8 kg
Formula Avg
57.3 kg
Input
Male, 180 cm
Recommended
75.4 kg
Healthy Range
59.9–80.7 kg
Formula Avg
72.1 kg
Input
Female, 160 cm
Recommended
55.9 kg
Healthy Range
47.4–63.7 kg
Formula Avg
54.3 kg
Frequently Asked Questions
What is the most accurate ideal weight formula?
No single formula is universally most accurate — each was developed for a specific population. The Devine formula is most widely used in clinical settings (especially for medication dosing). The average of all four formulas is the most balanced estimate for the general population.
Does ideal weight change with age?
The core formulas do not factor in age. However, older adults (particularly those over 65) may benefit from maintaining a slightly higher BMI (around 22–27) to reduce risk of osteoporosis and frailty. Always consult your doctor for age-specific guidance.
What if I'm very muscular or athletic?
Height-based ideal weight formulas do not account for muscle mass. Athletes and highly muscular individuals typically weigh more than formula estimates while remaining very healthy. For an accurate assessment, body fat percentage measurement is more informative than formula-based ideal weight.
How is ideal weight different from target weight?
Ideal weight is a statistical estimate based on your height and sex. Target weight is the specific weight you personally aim to reach, which may be influenced by ideal weight, current health status, fitness goals, and medical advice. Your target weight may differ from formula-based ideal weight.
How accurate are these formulas for people under 5 feet tall?
All four formulas were developed based on populations with heights near and above 5 feet. For individuals shorter than 5 feet (152 cm), the formulas may underestimate healthy weight. The BMI healthy weight range is generally considered more reliable for people below this threshold.
Should I aim to reach my ideal weight?
Not necessarily. These are reference estimates, not medical targets. If your current weight falls within the healthy BMI range, you are generally doing well even if you are slightly above the formula ideal weight. Focus on sustainable healthy habits rather than hitting an exact number.