Compare historical dosing formulas and healthy BMI ranges.
Clinically Audited
4-Formula Comparison
Healthy BMI Fallback
175 cm
cm
100 cm220 cm
Recommended Ideal Weight (Devine Formula)
70.5 kg
Visualization: Formulas vs. WHO Healthy BMI Range
Devine: 70.5kg
Robinson: 68.9kg
Miller: 68.8kg
Hamwi: 72.0kg
Min BMI: 56.7kg
Max BMI: 76.3kg
Devine Formula (1974)70.5 kg
Robinson Formula (1983)68.9 kg
Miller Formula (1983)68.8 kg
Hamwi Formula (1964)72.0 kg
Healthy BMI Weight Range (18.5 - 24.9):56.7 kg - 76.3 kg
How is this calculated? (Worked Math substitution)
Traditional formulas require a baseline height of 5 feet (60 inches / 152.4 cm).
Your height is 68.9 inches, which is 8.9 inches over 5 feet.
Devine: 50.0 + 2.3 × 8.9 = 70.5 kg
Robinson: 52.0 + 1.9 × 8.9 = 68.9 kg
Miller: 56.2 + 1.41 × 8.9 = 68.8 kg
Hamwi: 48.0 + 2.7 × 8.9 = 72.0 kg
References & Scientific Sources
Devine Formula: Devine BJ. Gentamicin therapy. Drug Intell Clin Pharm. 1974;8:650–655. View Paper
Robinson Formula: Robinson JD, et al. Evaluation of methods for estimating ideal body weight. Am J Hosp Pharm. 1983;40(6):1016-1019. PubMed
Miller Formula: Miller DR, et al. Clinical evaluation of three methods for calculating ideal body weight. Am J Hosp Pharm. 1983;40(6):1016-1019. PubMed
Hamwi Formula: Hamwi GJ. Changing concepts in status of diabetes. Am Diet Assoc. 1964;13:13-17.
Clinical Review: Pai MP, Paloucek FP. The origin of the "ideal" body weight equations. Ann Pharmacother. 2000;34(9):1066-1069. PubMed
About the Ideal Weight Calculator
Ideal Body Weight (IBW) is a clinical standard developed to estimate the optimal, healthy body mass of an individual based on height, biological sex, and bone frame. Initially conceived in 1964 by Dr. G.J. Hamwi for estimating diabetes diets and later popularized in 1974 by Dr. B.J. Devine, IBW calculations were designed primarily to standardize pharmacotherapy dosing (such as calculating clearances for narrow therapeutic index drugs like aminoglycosides or anesthetics). Because adipose tissue has less vascular perfusion than lean body mass, dosing certain medications based on actual weight in obese patients can lead to toxic overdoses. In addition to the Hamwi and Devine formulas, other widely cited clinical models include the Robinson and Miller equations. Modern healthcare practitioners combine these height-based formulas with healthy Body Mass Index (BMI) ranges (typically 18.5 to 24.9 kg/m²) to establish target healthy weights, while acknowledging that they do not account for muscle mass, age, or ethnic variations.
Mathematical Formula & Logic
Ideal Body Weight equations utilize a baseline weight for the first 5 feet (60 inches / 152.4 cm) of height, adding a fixed weight increment for each additional inch. BMI-based ranges are calculated using height in meters:
1. Devine Formula (1974):
- Men: IBW_kg = 50.0 + 2.3 × (Height_inches - 60)
- Women: IBW_kg = 45.5 + 2.3 × (Height_inches - 60)
2. Robinson Formula (1983):
- Men: IBW_kg = 52.0 + 1.9 × (Height_inches - 60)
- Women: IBW_kg = 49.0 + 1.7 × (Height_inches - 60)
3. Miller Formula (1983):
- Men: IBW_kg = 56.2 + 1.41 × (Height_inches - 60)
- Women: IBW_kg = 53.1 + 1.36 × (Height_inches - 60)
4. Hamwi Formula (1964):
- Men: IBW_kg = 48.0 + 2.7 × (Height_inches - 60)
- Women: IBW_kg = 45.5 + 2.2 × (Height_inches - 60)
5. Healthy BMI Range Limits (BMI of 18.5 to 24.9):
- Weight_min = 18.5 × (Height_meters)^2
- Weight_max = 24.9 × (Height_meters)^2
Step-by-Step Example
Calculate the ideal body weight for a male who is 175 cm tall using the Devine formula and find his healthy BMI weight range:
1. Convert height to inches: Height_inches = 175 / 2.54 ≈ 68.898 inches
2. Calculate inches over 5 feet: 68.898 - 60 = 8.898 inches
3. Apply Devine formula: IBW = 50.0 + 2.3 × 8.898 = 50.0 + 20.465 ≈ 70.5 kg (155.4 lbs)
4. Convert height to meters: Height_meters = 1.75 m
5. Calculate BMI healthy range limits:
- Weight_min = 18.5 × (1.75)^2 = 18.5 × 3.0625 ≈ 56.7 kg (125.0 lbs)
- Weight_max = 24.9 × (1.75)^2 = 24.9 × 3.0625 ≈ 76.3 kg (168.2 lbs)
6. The Devine ideal weight is 70.5 kg, and the healthy BMI weight range spans from 56.7 kg to 76.3 kg.
Reference Data & Values
height
gender
devine
robinson
bmi range
160 cm (5'3")
Female
52.4 kg
54.1 kg
47.4 - 63.7 kg
170 cm (5'7")
Female
61.5 kg
60.8 kg
53.5 - 72.0 kg
175 cm (5'9")
Male
70.5 kg
68.9 kg
56.7 - 76.3 kg
185 cm (6'1")
Male
79.6 kg
76.4 kg
63.3 - 85.2 kg
Frequently Asked Questions
Clinically, no single formula is universally more accurate. The Devine formula is the most widely used in hospital settings for drug dosing, while the Robinson and Miller formulas are newer refinements based on modern statistical tables.
All four traditional formulas use a baseline height of 5 feet (152.4 cm). If you are under 5 feet tall, these formulas are not clinically validated, and standard medical practice is to refer to the Healthy BMI Range instead.
Biological sex is used because men and women have different average skeletal proportions, bone densities, and muscle-to-fat ratios, which affect ideal weight guidelines.
No. Traditional ideal body weight formulas do not distinguish between muscle mass and fat mass. Therefore, muscular athletes may be flagged as overweight despite being extremely lean and healthy.
The Hamwi formula, developed in 1964, is an early bedside heuristic that estimates ideal body weight by adding 6 lbs (for men) or 5 lbs (for women) per inch above a 5-foot baseline.
Ideal weight is a strict mathematical estimation from clinical dosing formulas, whereas healthy weight is a broader range (usually based on a BMI of 18.5 to 24.9) that accommodates variations in body frame and muscle.
Seniors often experience changes in bone density and body composition. These formulas do not adjust for age, so consulting a physician is recommended for seniors.
If you are under 5 feet tall, traditional IBW formulas are not recommended. You should use the healthy BMI range as a reference and consult a healthcare provider.