Your Measurements
Weight Range Indicator
Ideal Weight by Formula
BMI Analysis
Formula Comparison Chart
Detailed Formula Breakdown
📖 How to Use
- Enter your height (in cm or feet/inches).
- Select your gender.
- Optionally set your age for more accurate results.
- Click Calculate — see your ideal weight range from multiple formulas.
❓ Frequently Asked Questions
Ideal Weight Calculator — Four Formulas, One Honest Answer
The concept of an "ideal body weight" has a more complex and clinically specific history than most people realise. The formulas used to calculate it were not designed for general wellness guidance — they were developed by pharmacologists and clinicians to calculate drug dosages based on body weight, since many medications (particularly those used in intensive care, anaesthesia, and nephrology) must be dosed against lean body mass rather than actual body weight.
Understanding this clinical origin helps put the result in perspective: your "ideal weight" from these formulas is a pharmacological reference point, not an aesthetic or health judgment. A person 10 kg above their formula-derived ideal weight can be perfectly healthy; someone exactly at their ideal weight might be unhealthy. The number is a useful starting reference, not a verdict.
The Four Ideal Body Weight Formulas
| Formula | Published | Men (kg) | Women (kg) | Primary Use |
|---|---|---|---|---|
| Devine | 1974 | 50 + 2.3 × (inches over 5 ft) | 45.5 + 2.3 × (inches over 5 ft) | Drug dosing (most clinical standard) |
| Robinson | 1983 | 52 + 1.9 × (inches over 5 ft) | 49 + 1.7 × (inches over 5 ft) | More conservative estimate |
| Miller | 1983 | 56.2 + 1.41 × (inches over 5 ft) | 53.1 + 1.36 × (inches over 5 ft) | Smaller frame reference |
| Hamwi | 1964 | 48 + 2.7 × (inches over 5 ft) | 45.5 + 2.2 × (inches over 5 ft) | Original dietetic reference |
Worked Example: Male, 175 cm (5 ft 9 in)
Height above 5 ft = 9 inches
- Devine: 50 + 2.3 × 9 = 50 + 20.7 = 70.7 kg
- Robinson: 52 + 1.9 × 9 = 52 + 17.1 = 69.1 kg
- Miller: 56.2 + 1.41 × 9 = 56.2 + 12.7 = 68.9 kg
- Hamwi: 48 + 2.7 × 9 = 48 + 24.3 = 72.3 kg
Range: 68.9–72.3 kg. The tool displays all four results and highlights the Devine formula (most clinically used) as the primary reference while showing the full range to illustrate that no single number is absolute.
Limitations of Ideal Weight Formulas
- No ethnic adjustment — all four formulas were developed on Western populations; South Asians often have lower lean mass at the same height
- No account for muscle mass — a muscular athlete will be well above formula ideal weight with very low body fat
- Height is the only variable — age, sex (used only to distinguish male/female), and frame size are not accurately reflected
- Not valid below 5 ft (152 cm) — formulas were designed for adults 5 ft and above; results become less reliable for shorter statures
Frequently Asked Questions
Which ideal weight formula is most accurate?
No single formula is universally accurate — each was developed for a specific clinical purpose and population. Devine is most commonly used in clinical pharmacology for drug dosing. For personal health tracking, the range across all four formulas gives a more useful picture than any single value. The true "ideal" weight for an individual depends on factors none of these formulas capture.
Should I try to reach my ideal body weight?
Not necessarily. These formulas define a pharmacological reference point, not an optimal health target. Many people are perfectly healthy at weights above their formula ideal. Rather than targeting a specific number, health professionals generally recommend focusing on: maintaining an active lifestyle, eating a balanced diet, keeping metabolic markers (blood pressure, blood glucose, cholesterol) in healthy ranges, and maintaining weight stability rather than constant fluctuation.
How is ideal body weight used in medicine?
In clinical settings, ideal body weight (IBW) is used to calculate doses of drugs that distribute in lean tissue (e.g., aminoglycosides, digoxin, some chemotherapy agents). For ventilator settings in ICU, tidal volume targets are often calculated per kg of predicted body weight (equivalent to IBW) to avoid lung injury. Using actual body weight in obese patients would lead to overdosing for these medications.
What is adjusted body weight (AdjBW)?
For obese patients, using pure IBW can underdose some medications (because obese patients have more adipose tissue that the drug does distribute into, partially). Adjusted body weight = IBW + 0.4 × (Actual weight − IBW). This is used for certain drug dose calculations and caloric requirement estimates in obese patients.
Is ideal body weight relevant for children?
No — these formulas are designed for adults. Paediatric ideal weight and growth assessment use age-specific weight-for-height and weight-for-age percentile charts from WHO or CDC growth standards. For children, refer to a paediatrician for proper growth assessment.