Ideal Weight Calculator
Calculate your ideal body weight using 5 different formulas: Robinson, Miller, Devine, Hamwi, and BMI-based. See also BMI Calculator and Body Fat Calculator.
How to Calculate Ideal Body Weight
Ideal body weight (IBW) is an estimated weight considered healthiest for a person based on their height and gender. Multiple formulas exist because there is no single perfect method. This calculator uses five well-known formulas and averages them for a balanced estimate. All formulas use height as the primary input, with adjustments for gender differences in body composition.
Ideal Weight Formulas
Devine Formula (1974)
Male: IBW = 50 + 2.3 × (height in inches − 60)
Female: IBW = 45.5 + 2.3 × (height in inches − 60)
Robinson Formula (1983)
Male: IBW = 52 + 1.9 × (height in inches − 60)
Female: IBW = 49 + 1.7 × (height in inches − 60)
Miller Formula (1983)
Male: IBW = 56.2 + 1.41 × (height in inches − 60)
Female: IBW = 53.1 + 1.36 × (height in inches − 60)
Example (Male, 5'9" / 175 cm)
Height = 69 inches, inches over 5ft = 9
Devine: 50 + 2.3 × 9 = 70.7 kg (155.9 lbs)
Robinson: 52 + 1.9 × 9 = 69.1 kg (152.3 lbs)
Miller: 56.2 + 1.41 × 9 = 68.9 kg (151.9 lbs)
Ideal Weight by Height Table
| Height | Male (kg) | Female (kg) |
|---|---|---|
| 5'0" (152 cm) | 50.0 – 57.0 | 45.5 – 53.1 |
| 5'2" (157 cm) | 54.6 – 59.8 | 50.1 – 55.8 |
| 5'4" (163 cm) | 59.2 – 62.6 | 54.7 – 58.5 |
| 5'6" (168 cm) | 63.8 – 65.4 | 59.3 – 61.2 |
| 5'8" (173 cm) | 68.4 – 68.2 | 63.9 – 63.9 |
| 5'10" (178 cm) | 73.0 – 71.0 | 68.5 – 66.6 |
| 6'0" (183 cm) | 77.6 – 73.8 | 73.1 – 69.3 |
| 6'2" (188 cm) | 82.2 – 76.6 | 77.7 – 72.0 |
Frequently Asked Questions
Which ideal weight formula is most accurate?
No single formula is universally best. The Devine formula is most widely used in clinical settings. The Robinson and Miller formulas are considered more modern refinements. Using the average of multiple formulas gives the most balanced estimate.
Does ideal weight account for body composition?
No. These formulas only use height and gender. They do not account for muscle mass, bone density, age, or body frame size. A muscular person may weigh more than their "ideal weight" while being perfectly healthy.
Is ideal weight the same as healthy weight?
Not exactly. Ideal weight formulas give a single target, while healthy weight is a range. The BMI-based healthy range (18.5–24.9) is generally more useful for assessing whether your weight is in a healthy zone.
Solved Examples
Example 1: Ideal Weight for a Male, 5'9" (175 cm) Using All Formulas
Solution:
Height in inches = 69, inches over 5 ft = 9
Devine: 50 + 2.3 × 9 = 70.7 kg (155.9 lbs)
Robinson: 52 + 1.9 × 9 = 69.1 kg (152.3 lbs)
Miller: 56.2 + 1.41 × 9 = 68.9 kg (151.9 lbs)
Hamwi: 48 + 2.7 × 9 = 72.3 kg (159.4 lbs)
BMI-based (21.75): 21.75 × (1.75)² = 21.75 × 3.0625 = 66.6 kg
Average: (70.7 + 69.1 + 68.9 + 72.3 + 66.6) ÷ 5 = 69.5 kg
Answer: Ideal weight ≈ 69.5 kg (153.2 lbs) — range: 66.6 to 72.3 kg
Example 2: Ideal Weight for a Female, 5'4" (163 cm)
Solution:
Height in inches = 64, inches over 5 ft = 4
Devine: 45.5 + 2.3 × 4 = 54.7 kg (120.6 lbs)
Robinson: 49 + 1.7 × 4 = 55.8 kg (123.0 lbs)
Miller: 53.1 + 1.36 × 4 = 58.5 kg (129.0 lbs)
Hamwi: 45.5 + 2.2 × 4 = 54.3 kg (119.7 lbs)
BMI-based: 21.75 × (1.63)² = 21.75 × 2.6569 = 57.8 kg
Average: (54.7 + 55.8 + 58.5 + 54.3 + 57.8) ÷ 5 = 56.2 kg
Answer: Ideal weight ≈ 56.2 kg (123.9 lbs)
Example 3: Healthy Weight Range Using BMI (Male, 180 cm)
Solution:
Height in meters: 1.80 m, Height² = 3.24 m²
Minimum (BMI 18.5): 18.5 × 3.24 = 59.9 kg
Maximum (BMI 24.9): 24.9 × 3.24 = 80.7 kg
Midpoint (BMI 21.75): 21.75 × 3.24 = 70.5 kg
Answer: Healthy range = 59.9 to 80.7 kg, midpoint = 70.5 kg
Practice Questions
Q1: Calculate the Devine ideal weight for a male who is 6'0" (183 cm).
Answer: Inches over 5 ft = 12. Devine = 50 + 2.3 × 12 = 77.6 kg (171.1 lbs)
Q2: A woman is 5'2" (157 cm). What is her Robinson ideal weight?
Answer: Inches over 5 ft = 2. Robinson (female) = 49 + 1.7 × 2 = 52.4 kg (115.5 lbs)
Q3: Which formula gives the highest ideal weight for a 6'2" male — Devine or Hamwi?
Answer: Inches over 5 ft = 14. Devine = 50 + 2.3×14 = 82.2 kg. Hamwi = 48 + 2.7×14 = 85.8 kg. Hamwi gives a higher value.
Q4: A man weighs 95 kg at 175 cm. How far is he from his Devine ideal weight?
Answer: Devine ideal = 50 + 2.3 × 9 = 70.7 kg. Difference = 95 − 70.7 = 24.3 kg above ideal weight.
Q5: For a 5'6" female, what is the healthy BMI weight range?
Answer: Height = 168 cm = 1.68 m, height² = 2.8224. Min: 18.5 × 2.8224 = 52.2 kg. Max: 24.9 × 2.8224 = 70.3 kg. Range: 52.2–70.3 kg.
Common Mistakes to Avoid
The most common mistake with ideal weight calculations is treating the result as an exact target rather than a reference point within a healthy range. These formulas were developed for population averages and do not account for individual factors like muscle mass, bone structure, or body composition — a muscular athlete may weigh significantly more than their "ideal" while being perfectly healthy. Another error is using formulas designed for adults on adolescents or children, who have different growth patterns. People also frequently confuse ideal weight with their goal weight — someone with a large frame or athletic build should target the higher end of the range. The Devine formula (most commonly used in medicine for drug dosing) was never designed as a fitness target, yet it's often misapplied this way. Finally, focusing solely on a number on the scale ignores body composition: two people at the same weight and height can have vastly different health profiles depending on their muscle-to-fat ratio.
Key Takeaways
- No single formula gives the "correct" ideal weight — averaging multiple formulas provides a more balanced estimate.
- All formulas use height as the primary variable; they do not account for age, muscle mass, or frame size.
- The BMI-based healthy range (18.5–24.9) gives a wider and often more realistic target than single-point formulas.
- The Devine formula is most commonly used in clinical medicine, while Robinson and Miller are considered more modern refinements.
- Ideal weight should be viewed as a range, not a fixed number — a 5–10 kg window around the average is perfectly normal.
- Body composition (muscle vs fat) matters more than scale weight — combine ideal weight with body fat percentage for a complete picture.