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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.
Ideal Weight Calculator
Calculate your ideal body weight using multiple scientific formulas including Robinson, Miller, Devine, and Hamwi.
Expert reviewer: CalculatorApp.me Health Editorial Team
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Ideal body weight (IBW) is a clinically derived target weight for a given height. Four main formulas — Robinson (1983): men 52 kg + 1.9 kg/inch over 5 ft; Devine (1974): men 50 kg + 2.3 kg/inch over 5 ft; Miller (1983): men 56.2 kg + 1.41 kg/inch over 5 ft; Hamwi (1964): men 106 lb + 6 lb/inch over 5 ft — produce slightly different estimates. IBW was developed for clinical drug dosing (adjusted body weight = IBW + 0.4 × (actual − IBW)) and nutrition assessments, not cosmetic fitness targets. Average adult IBW ranges from ~55–70 kg (women) to ~60–80 kg (men) for heights of 5′2″–5′11″.
📚 Ideal Body Weight — Complete Guide
Reviewed by CalculatorApp.me Health Editorial Team · Updated March 2026 · 10 min read
4
Scientific Formulas
±10%
Frame Adjustment
60+
Years of Research
12
FAQ Answers
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What Is Ideal Body Weight?
Ideal body weight (IBW) is a clinically-derived target weight based on height and biological sex. Originally developed to standardize medication dosing, IBW is now a core metric in preventive care, sports nutrition, and rehabilitation planning.
Unlike BMI, which is a ratio, IBW gives you an absolute weight range in kg or lbs — making goal-setting concrete and measurable. Per the WHO, 1.9 billion adults are overweight while 462 million are underweight — IBW supports both contexts.
🔗 Related tools on this site
5 Evidence-Based Facts
- 1A 5–10% weight reduction cuts Type 2 diabetes risk by 58% (NEJM, 2002).
- 2Losing 0.5–1 kg/week preserves muscle far better than rapid cuts.
- 3The Devine formula is the global pharmacokinetics gold standard.
- 4Waist circumference + IBW predicts cardiovascular risk more accurately than scale weight alone.
- 5Maintaining IBW range lowers hypertension risk by 30–40%.
The 4 Validated IBW Formulas
♂ Men: 50 + 2.3 × (inches − 60)
♀ Women: 45.5 + 2.3 × (inches − 60)
Original drug-dosing formula. Most cited in pharmacokinetics literature.
♂ Men: 52 + 1.9 × (inches − 60)
♀ Women: 49 + 1.7 × (inches − 60)
Broader population sample. Preferred in wellness and fitness contexts.
♂ Men: 56.2 + 1.41 × (inches − 60)
♀ Women: 53.1 + 1.36 × (inches − 60)
Most generous values. Best for taller individuals and large frames.
♂ Men: 48 + 2.7 × (inches − 60)
♀ Women: 45.5 + 2.2 × (inches − 60)
First bedside clinical formula. Foundational for dietetics education.
Clinical Disclaimer: These formulas do not account for muscle mass, bone density, ethnicity, or body fat distribution. Athletes routinely exceed IBW while being metabolically healthy. Pregnant women, under-18s, and those with chronic conditions should consult a licensed healthcare provider before setting any weight targets.
History & Origins of IBW
Ideal weight science spans 160 years — from actuarial insurance tables to ICU ventilator protocols. Understanding its history helps you interpret your results with the right clinical context.
Metropolitan Life Insurance published the first height-weight tables correlating body weight with longevity. Limited to White, middle-class American men, but established the height-based weight norm paradigm still used today.
Dr. G. J. Hamwi created the first practical bedside formula for dietitians: 106 lbs for men or 100 lbs for women at 5 ft, adding 6 or 5 lbs per additional inch. Easy to calculate mentally during ward rounds without a calculator.
Dr. B. J. Devine solved the drug-overdose problem for obese patients by publishing an IBW formula specifically for calculating medication doses with narrow therapeutic windows (aminoglycosides, vancomycin, anesthesia agents).
Two independent research groups refined IBW coefficients for broader populations. Robinson is preferred for lifestyle use; Miller is most generous and suits taller individuals.
The National Institutes of Health published BMI-based classification guidelines, creating a parallel system to IBW. Both tools are now used together in clinical settings.
The landmark ARDSNet study proved that IBW-based mechanical ventilator tidal volume settings reduced ICU mortality by 22%. Published in the New England Journal of Medicine.
Modern tools combine IBW with body composition, waist metrics, and cardiometabolic markers. Multi-formula comparison — like this calculator — is now the evidence-based standard.
Worked Examples
Example A
Male · 5 ft 10 in · Medium Frame
| Formula | kg | lbs |
|---|---|---|
| Devine | 73.0 kg | 160.9 lbs |
| Robinson | 71.0 kg | 156.5 lbs |
| Miller | 70.3 kg | 155.0 lbs |
| Hamwi | 75.0 kg | 165.3 lbs |
Avg: 72.3 kg
70.3 – 75.0 kg
Example B
Female · 5 ft 4 in · Small Frame (−10%)
| Formula | kg | lbs |
|---|---|---|
| Devine | 54.7 kg | 120.6 lbs |
| Robinson | 55.8 kg | 123.0 lbs |
| Miller | 58.5 kg | 129.0 lbs |
| Hamwi | 54.3 kg | 119.7 lbs |
Avg: ~50.2 kg
Adjusted for small frame
Example C
Female · 5 ft 8 in · Large Frame (+10%)
| Formula | kg | lbs |
|---|---|---|
| Devine | 63.9 kg | 140.9 lbs |
| Robinson | 62.6 kg | 137.9 lbs |
| Miller | 64.0 kg | 141.1 lbs |
| Hamwi | 63.1 kg | 139.1 lbs |
Avg: ~69.7 kg
Adjusted for large frame
IBW vs BMI vs Body Fat — Full Comparison
Each metric measures something different. Use them as a layered system — not as competing alternatives — for the most accurate health picture. Compare with our BMI Calculator and Body Fat Calculator.
| Metric | Measures | Best For | Key Limitation |
|---|---|---|---|
| ⚖️ IBW | Estimated target weight (kg/lbs) from height + sex | Goal setting, drug dosing, clinical planning | No body composition; height-only input |
| 📊 BMI | Weight ÷ Height² ratio (kg/m²) | Population screening, quick risk triage | Misclassifies athletes; no fat distribution info |
| 💪 Body Fat % | Percentage of mass that is fat tissue | Composition analysis, athletic performance | Requires DEXA/BIA device for accuracy |
| 📏 Waist Circumference | Abdominal girth (proxy for visceral fat) | CV & metabolic risk (WHO: >88 cm women, >102 cm men) | Single dimension; not full composition picture |
Where IBW Is Used
Pharmacokinetics & Drug Dosing
Drugs with narrow therapeutic windows (gentamicin, vancomycin, chemotherapy, anesthesia) are dosed on IBW to prevent toxicity in obese patients. This remains the most clinically validated use of the Devine formula.
ICU Nutrition Support
Critical care teams use IBW to calculate calorie and protein targets for enteral/parenteral nutrition. Using actual weight in obese patients overestimates energy needs, worsening hyperglycemia and infection risk.
Mechanical Ventilation
Ventilator tidal volumes are set by PBW (= IBW). The ARDSNet trial (NEJM 2000) proved 6 mL/kg IBW-based settings reduced ICU mortality by 22% vs. actual-weight-based settings. NEJM ARDSNet Trial ↗
Bariatric Surgery
Surgical eligibility typically requires 100+ lbs over IBW or BMI ≥ 40. Post-op progress is tracked as "excess weight loss %" relative to IBW — a standard outcome metric in bariatric research.
Dietetics & Nutrition Therapy
Registered Dietitians set calorie and macro targets based on IBW rather than actual weight to create sustainable plans. The Harris-Benedict and Mifflin-St Jeor equations are often run using IBW in overweight patients. See our BMR Calculator →
Sports & Fitness
Coaches use IBW to set realistic category targets for weight-class sports and discuss body composition goals. Endurance athletes often target below-IBW weights to optimize power-to-weight ratio under sports medicine supervision.
Age & Gender Considerations
📅 By Age Group
IBW formulas are most accurate. Lean mass is at peak; standard ranges align well with health outcomes.
Sarcopenia begins (3–5% muscle/decade). May be "in IBW range" but have high body fat. Add waist measurement.
The "obesity paradox" (Flegal et al., JAMA 2013) suggests slightly higher weight may be protective. Prioritize lean mass over strict IBW adherence.
⚧ By Biological Sex
♂ Men
- • High muscle mass (BMI >25, body fat <18%) → above IBW is normal and healthy.
- • Testosterone decline after 40 → visceral fat rises even at stable weight.
♀ Women
- • Menstrual cycle → 1–3 kg water fluctuation. Use 4-week trend, not single weigh-in.
- • Post-menopause fat shifts to abdomen → waist > scale weight as risk marker.
- • Never use IBW during pregnancy — consult OB/GYN for gestational weight gain targets.
Scientific Research Base
Pai & Paloucek (2000)
Annals of Pharmacotherapy
Traced the origins of all four IBW equations; recommended reporting multiple formula variants to avoid clinical bias.
ARDSNet Trial (2000)
New England Journal of Medicine
IBW-based ventilator volumes (6 mL/kg) cut ICU mortality by 22% vs. actual-weight volumes. Landmark critical care evidence.
NDPP — Knowler et al. (2002)
New England Journal of Medicine
5–7% weight loss reduced incidence of Type 2 diabetes by 58%, validating IBW-range lifestyle goals.
Flegal et al. (2013)
JAMA
Meta-analysis of 2.88 million adults: slight overweight (BMI 25–30) associated with lower all-cause mortality over 65 — the obesity paradox.
Kyle UG et al. (2003)
Clinical Nutrition
BIA study: IBW formulas underestimate lean mass in taller individuals, reinforcing the need for frame-size adjustments.
WHO Waist Report (2011)
WHO Press
Established global waist-circumference risk thresholds (>88 cm women, >102 cm men) as complement to IBW assessment.
Expert Advice by Goal
Above Your IBW Range
- •500–750 kcal daily deficit → 0.5–0.75 kg/week loss without muscle sacrifice.
- •1.6–2.2 g protein per kg bodyweight daily to preserve lean mass.
- •Resistance training 3×/week + 150+ min aerobic activity/week (WHO guideline).
- •Track waist circumference monthly — abdominal fat loss precedes scale movement.
- •Prioritize sleep (7–9 hrs) and stress management to reduce cortisol-driven fat storage.
- •Expect 9–12 months to reach IBW from 20 kg above — plan the program, not the sprint.
Below Your IBW Range
- •300–500 kcal daily surplus from protein + complex carbs (not saturated fats).
- •Target 0.25–0.5 kg gain/week — slow gain maximizes lean tissue build.
- •Progressive overload resistance training 3× /week to direct surplus to muscle.
- •5–6 smaller meals if large volumes are uncomfortable.
- •Unexplained persistent weight loss despite adequate intake → seek medical review immediately.
- •Use our BMR Calculator to calculate your specific calorie surplus target.
Within Your IBW Range
- •Shift focus to strength benchmarks, VO₂ max, and cardiometabolic markers (glucose, BP, cholesterol).
- •Recalculate IBW every 6–12 months — composition shifts even when weight is stable.
- •Resistance training 2–3×/week is the #1 evidence-based longevity behavior after quitting smoking.
See a Doctor If…
- •Unintentional weight loss >5% body weight in 6–12 months without lifestyle change.
- •Persistent fatigue, hair loss, cold intolerance — possible thyroid dysfunction or anemia.
- •Edema causing >2 kg day-to-day weight swings.
- •Diagnosed with diabetes, heart disease, kidney disease, or eating disorder.
- •Pregnant, breastfeeding, or recovering from major surgery.
Myths vs. Facts
Myth
Everyone at the same height should weigh exactly the same.
Fact
IBW formulas provide a range, not a single target. Frame size, bone density, muscle mass, and health status all legitimately shift what is appropriate. Even the four standard formulas disagree by up to 5 kg for the same person.
Myth
If I am over my IBW, I am unhealthy.
Fact
Athletes with high muscle mass routinely exceed IBW while having excellent cardiometabolic markers. IBW is a planning guide, not a clinical diagnosis. Health involves blood markers, fitness, and body composition — not just the scale.
Myth
IBW formulas are outdated and no longer clinically used.
Fact
IBW-based dosing remains the standard in pharmacokinetics, ICU ventilation, and critical care nutrition. The ARDSNet ventilator trial saved thousands of lives using IBW. Medical schools still teach these formulas worldwide.
Myth
Reaching IBW as quickly as possible is the best strategy.
Fact
Rapid weight loss (>1 kg/week sustained) causes lean mass loss, hormonal disruption, nutrient deficiencies, and metabolic rate suppression. Gradual change consistently outperforms fast approaches for long-term maintenance.
Myth
IBW and BMI measure the same thing.
Fact
IBW is an absolute weight in kg or lbs. BMI is a dimensionless ratio (kg/m²). They correlate but serve different purposes. A very tall person can exceed IBW with a normal BMI; a short person can be at IBW with a slightly elevated BMI.
Frequently Asked Questions
Is ideal weight the same as healthy weight?+
Which IBW formula is the most accurate?+
Why does frame size matter in IBW calculations?+
Does ideal weight change with age?+
Is this calculator valid for children and teenagers?+
Can athletes use this calculator?+
Should I target the minimum, average, or maximum of my IBW range?+
Can ideal weight help me calculate daily calorie needs?+
What is the difference between IBW and Adjusted Body Weight (ABW)?+
How do I determine my frame size accurately?+
Why does my result differ from other IBW calculators?+
Is this tool suitable for medical decisions?+
References & Further Reading
- 1.Devine BJ. Gentamicin therapy. Drug Intelligence and Clinical Pharmacy. 1974;8:650–655.View ↗
- 2.Robinson JD et al. Determination of ideal body weight for drug dosage calculations. Am J Hosp Pharm. 1983;40(6):1016–1019.View ↗
- 3.Miller DR et al. Determining ideal body weight. Am J Hosp Pharm. 1983;40(10):1622.View ↗
- 4.Pai MP, Paloucek FP. The origin of the "ideal" body weight equations. Ann Pharmacother. 2000;34(9):1065–1069.View ↗
- 5.ARDSNet. Ventilation with lower tidal volumes for ALI/ARDS. N Engl J Med. 2000;342:1301–1308.View ↗
- 6.Knowler WC et al. (NDPP). Reduction in incidence of type 2 diabetes with lifestyle intervention. N Engl J Med. 2002;346:393–403.View ↗
- 7.Flegal KM et al. Association of all-cause mortality with overweight and obesity. JAMA. 2013;309(1):71–82.View ↗
- 8.WHO. Waist circumference and waist-hip ratio: Expert Consultation report. Geneva: WHO Press; 2011.View ↗
- 9.NIH. Clinical guidelines on identification, evaluation, and treatment of overweight and obesity in adults. Obes Res. 1998;6(Suppl 2).View ↗
This page is reviewed periodically by our Clinical Advisory Board. All content is for educational use only and does not constitute medical advice. For personalized guidance consult a qualified healthcare professional.
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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.