liminfoIdeal Weight Calculator
Free web tool: Ideal Weight Calculator
Devine Formula
65.9 kg
145.4 lbs
Robinson Formula
65.2 kg
143.7 lbs
Miller Formula
66.0 kg
145.5 lbs
Hamwi Formula
66.7 kg
147.1 lbs
Healthy BMI Range (18.5-24.9)
53.5 - 72.0 kg
Formula Average
65.9 kg
About Ideal Weight Calculator
The Ideal Weight Calculator computes your ideal body weight using four clinically established formulas simultaneously: Devine (1974), Robinson (1983), Miller (1983), and Hamwi (1964). Each formula was developed for specific clinical contexts—the Devine formula originated in pharmacology for drug dosing, Robinson and Miller were derived from life insurance actuarial data, and Hamwi is widely used by dietitians. By presenting all four results side-by-side, this tool lets you understand the range of opinion in the medical literature rather than relying on a single arbitrary number.
The calculator accepts height in centimeters or feet and inches, and accepts male or female gender to apply the correct formula variant. For every formula, ideal weight is computed by starting from a base weight at 5 feet (60 inches) and adding a per-inch increment above that threshold. For example, the Devine formula gives 50 kg for a 5-foot male plus 2.3 kg per additional inch of height. Results are displayed in both kilograms and pounds. The tool also shows the healthy BMI weight range (BMI 18.5–24.9) computed from your height for additional context.
Ideal weight formulas are best understood as statistical guidelines rather than absolute targets. Body composition, muscle mass, bone density, age, and ethnicity all affect what a healthy weight looks like for an individual. Clinicians typically use these formulas for medication dosing calculations (e.g., tidal volume in mechanical ventilation) rather than as fitness goals. Always consult a healthcare professional for personalized weight management advice.
Key Features
- Four simultaneous calculations: Devine, Robinson, Miller, and Hamwi formulas
- Male and female variants with gender-specific base weights and per-inch increments
- Height input in centimeters or feet and inches with automatic conversion
- Results displayed in both kilograms and pounds for international users
- Formula average displayed to give a consensus estimate across all four methods
- Healthy BMI range (18.5–24.9) shown as a weight range for your specific height
- Real-time computation — results update instantly as you change any input
- 100% client-side processing — no health data transmitted to any server
Frequently Asked Questions
What is the Devine ideal weight formula?
The Devine formula (1974) calculates ideal body weight as 50 kg (males) or 45.5 kg (females) for a height of 5 feet, plus 2.3 kg for each inch above 5 feet. It was originally developed by Dr. B.J. Devine for drug dosing in pharmacology and is still used in clinical settings for calculating adjusted body weight and medication doses.
How does the Robinson formula differ from Devine?
The Robinson formula (1983) starts at 52 kg (males) or 49 kg (females) at 5 feet and adds 1.9 kg/inch (males) or 1.7 kg/inch (females) for each inch above 5 feet. It was derived from life insurance actuarial data and tends to produce slightly higher ideal weights than Devine for taller individuals.
What is the Hamwi formula used for?
The Hamwi formula (1964) starts at 48 kg (males) or 45.5 kg (females) at 5 feet, adding 2.7 kg/inch (males) or 2.2 kg/inch (females). It is widely used by registered dietitians for nutritional assessment and meal planning, as it was specifically developed for clinical nutrition practice.
Which ideal weight formula is most accurate?
No single formula is universally more accurate. Each was developed in a different clinical context. The Devine formula is most commonly used in pharmacology and critical care medicine. Robinson and Miller are used in general medicine. Hamwi is preferred in nutrition counseling. The average of all four gives a reasonable consensus estimate. None should be treated as a precise target.
Should I try to reach my calculated ideal weight?
Ideal weight formulas were designed as statistical averages and clinical references, not personal fitness targets. Muscle weighs more than fat, so athletes may exceed these ranges while being perfectly healthy. The healthy BMI range (18.5–24.9) shown in this calculator provides a complementary perspective. Consult a doctor or registered dietitian for personalized guidance.
What is the healthy BMI range shown in the results?
The BMI-based weight range shows the minimum weight at BMI 18.5 and the maximum at BMI 24.9 for your entered height. This range is calculated as BMI × height(m)². A BMI below 18.5 is considered underweight; 25–29.9 is overweight; 30+ is obese, according to WHO classification. BMI has known limitations for muscular individuals and older adults.
Why do the four formulas give different results?
The four formulas were developed independently by different researchers using different reference populations, time periods, and methodologies. They encode slightly different assumptions about the relationship between height and healthy body weight. The spread of results reflects genuine uncertainty in the medical literature about what "ideal" weight means for any given individual.
Does this calculator work for people under 5 feet tall?
The ideal weight formulas are based on inches above 60 inches (5 feet). For heights below 5 feet, the "over 60 inches" term becomes zero or negative, which can produce unreliable results. The calculator accepts heights from 100 cm (about 3'3") to 250 cm, but results for heights well below 5 feet should be interpreted cautiously. Consult a pediatric or clinical specialist for below-average height assessments.