Ideal Weight Calculator
Calculate your ideal body weight using multiple formulas (Devine, Robinson, Miller). Get healthy weight range based on height, age, and gender. Free tool.
Reviewed by CalculatorApp.me Health Team
Ideal Weight Calculator — Complete Guide
Hamwi, Devine, Robinson, and Miller formulas, healthy BMI weight ranges, and clinical interpretation of ideal body weight.
4
IBW formulas compared
18.5–24.9
Healthy BMI weight range
±10%
Normal frame size variation
2.3 kg
Per inch over 5 ft (Hamwi men)
What Is Ideal Body Weight (IBW)?
Ideal Body Weight (IBW) refers to a target body weight associated with optimal health outcomes for a given height. It is primarily used in clinical medicine for dosing medications, anaesthesia, ventilator settings, and nutritional planning — not as a personal aesthetic target. IBW represents the weight at which health risks from both underweight and overweight are minimised.
Several formulas were developed in the 1960s and 1970s to create quick bedside estimates for clinical use. The most common — Hamwi, Devine, Robinson, and Miller — were not derived from large epidemiological datasets but from clinical observations. Today, they are best used as starting estimates, with BMI-based healthy ranges providing a more evidence-based complement.
It is important to recognise that "ideal weight" is a range, not a single number. Two people of the same height can have very different optimal weights depending on muscle mass, bone density, age, sex, and ethnicity. Frame size — whether small, medium, or large — can shift ideal weight by 10% in either direction.
Ideal Body Weight Formulas
Men: IBW = 48 kg + 2.7 kg per inch over 5 ft Women: IBW = 45.5 kg + 2.2 kg per inch over 5 ft Examples: Man, 5'10" (70 inches → 10 inches over 5 ft): IBW = 48 + 2.7(10) = 48 + 27 = 75 kg IBW range = 67.5 – 82.5 kg (±10%) Woman, 5'5" (65 inches → 5 inches over 5 ft): IBW = 45.5 + 2.2(5) = 45.5 + 11 = 56.5 kg IBW range = 50.9 – 62.2 kg (±10%) Under 5 ft: Men: 48 − 2.7 × (60 − height in inches) Women: 45.5 − 2.2 × (60 − height in inches)
The Hamwi formula was developed for clinical use by diabetologist G.J. Hamwi in 1964. It is still the most commonly used IBW formula in hospitals and clinical nutrition practice.
Men: IBW = 50 kg + 2.3 kg per inch over 5 ft Women: IBW = 45.5 kg + 2.3 kg per inch over 5 ft Note: Same as Hamwi for women; slightly different for men (+2.3 vs +2.7/inch) Examples: Man, 6'0" (72 inches → 12 inches over 5 ft): IBW = 50 + 2.3(12) = 50 + 27.6 = 77.6 kg Woman, 5'8" (68 inches → 8 inches over 5 ft): IBW = 45.5 + 2.3(8) = 45.5 + 18.4 = 63.9 kg Most commonly cited in pharmacokinetics for drug dosing, particularly renal clearance calculations and anaesthesia.
The Devine formula was published in a Drug Intelligence paper and became widely adopted for pharmacokinetic drug dosing. It is still the standard for creatinine clearance estimation and anaesthesia weight-based dosing.
Men: IBW = 52 kg + 1.9 kg per inch over 5 ft Women: IBW = 49 kg + 1.7 kg per inch over 5 ft Examples: Man, 5'10" (10 inches over 5 ft): IBW = 52 + 1.9(10) = 52 + 19 = 71 kg Woman, 5'6" (6 inches over 5 ft): IBW = 49 + 1.7(6) = 49 + 10.2 = 59.2 kg Comparison at 5'10" male: Hamwi: 75 kg | Devine: 72.6 kg Robinson: 71 kg | Miller: 68 kg Robinson tends to give lower estimates than Hamwi and Devine, particularly for taller individuals.
Robinson et al. derived this formula in 1983 from a large dataset of adults. It generally gives more conservative (lower) weight targets than Hamwi, which some researchers consider more appropriate for most body types.
Healthy weight = BMI 18.5–24.9 Weight range for BMI 18.5–24.9: Weight (kg) = BMI × height² (m²) Example: 5'10" = 1.78 m: Lower (BMI 18.5): 18.5 × 1.78² = 58.6 kg Upper (BMI 24.9): 24.9 × 1.78² = 78.9 kg Healthy range: 58.6 – 78.9 kg Example: 5'5" = 1.65 m: Lower (BMI 18.5): 18.5 × 1.65² = 50.3 kg Upper (BMI 24.9): 24.9 × 1.65² = 67.7 kg Healthy range: 50.3 – 67.7 kg BMI-range approach is most consistent with WHO and CDC health guidance.
The BMI 18.5–24.9 approach gives a range rather than a single target, which better reflects the reality that optimal weight varies significantly within the same height due to body composition differences.
Adjusting for Frame Size
Small Frame
Subtract 10%
Wrist circumference smaller than typical for height; visible bone structure
Medium Frame
Use IBW as-is
Wrist circumference within typical range; average bone density
Large Frame
Add 10%
Wrist circumference larger than typical; dense bone structure
Wrist Circumference Method
Women (height > 5'5") Men Wrist < 6.0" → Small Wrist < 6.5" → Small Wrist 6.0–6.5" → Medium Wrist 6.5–7.5" → Medium Wrist > 6.5" → Large Wrist > 7.5" → Large
Frequently Asked Questions
Are ideal weight formulas accurate for modern populations?▼
The Hamwi, Devine, Robinson, and Miller formulas were developed in the 1960s–1980s on limited datasets. They are clinical tools for drug dosing and ventilator management — not personal health targets. The BMI-based healthy weight range (18.5–24.9 kg/m²) is better supported by modern epidemiological research for individual health guidance.
What is a healthy weight for my height?▼
A healthy weight range corresponds to BMI 18.5–24.9. For a 5'8" (173 cm) adult, that is 57–80 kg. The ideal point within that range depends on your muscle mass, bone density, age, and fitness goals. An athletic person with high lean mass may feel best at the upper end; a sedentary person may benefit from the lower half.
Should I aim for a specific number on the scale?▼
Weight is just one metric. Body fat percentage, waist circumference, blood pressure, blood glucose, and fitness level are equally — or more — important indicators of health. Many clinicians now use waist-to-height ratio (<0.5) as a more meaningful target than any specific body weight.
References & Clinical Sources
- Hamwi GJ. Changing dietary concepts. In: Danowski TS (ed), Diabetes Mellitus: Diagnosis and Treatment. 1964.
- Devine BJ. Gentamicin therapy. Drug Intelligence Clin Pharmacy. 1974;8:650–5.
- Robinson JD, et al. Estimation of ideal body weight. Clin Pharmacy. 1983;2:56–8.
- Pai MP, Paloucek FP. The origin of the ideal body weight equations. Ann Pharmacother. 2000;34(9):1066–9.
Methodology, sources & limitations
This calculator uses a published formula and the values entered in the calculator to generate the result.
- Formula
- IBW(male) = 50 + 2.3×(height_in - 60); IBW(female) = 45.5 + 2.3×(height_in - 60)
- Jurisdiction & units
- Intended for US, IN, EU, GB, Global. Supports both units where applicable.
- Assumptions & limitations
- Results are screening or educational estimates based on the inputs you provide. They do not diagnose, treat, or replace advice from a qualified clinician.
- Review status
- Formula and automated QA completed June 21, 2026; independent professional review is pending. Next scheduled review: September 21, 2026.
Validation sources
- Devine BJ (1974)
- Robinson et al. (1983)
- Miller et al. (1983)
- Hamwi GJ (1964)
Ideal Weight Calculator — Answer & Method
Calculate ideal body weight using multiple validated formulas (Devine, Robinson, Miller, Hamwi).
Formula: Devine Formula
IBW(male) = 50 + 2.3×(height_in - 60); IBW(female) = 45.5 + 2.3×(height_in - 60)
Example Calculation
A 5'10" male has an ideal weight of approximately 72.7 kg (160 lbs) by the Devine formula.
Important limitation
This is an educational estimate, not a diagnosis or a substitute for professional medical advice.
Key Facts
- The Devine formula is the most commonly used ideal weight formula in clinical settings.
- Ideal weight calculations are estimates and do not account for muscle mass or body composition.