Which IBW formula is most accurate?

No single formula is universally most accurate. The Devine formula is the most widely used in clinical practice, especially for drug dosing. Robinson is considered slightly more accurate for women. All four formulas are shown so you can compare.

What is adjusted body weight?

Adjusted body weight (ABW) is used for drug dosing when actual weight exceeds IBW by more than 20%. Formula: ABW = IBW + 0.4 × (actual weight − IBW). It accounts for increased drug distribution in obese patients.

Is IBW the same as a healthy weight?

IBW formulas were developed for clinical drug dosing, not as health targets. A healthy weight range (BMI 18.5–24.9) may differ from IBW, especially for muscular individuals. Use IBW alongside BMI and body fat % for context.

Can I use IBW for drug dosing?

Yes. IBW is used for dosing weight-sensitive drugs (e.g. aminoglycosides, digoxin, heparin) in clinical practice. Always verify dosing with a pharmacist using current guidelines.

What if I am shorter than 5 feet (152 cm)?

The standard IBW formulas are less reliable for adults under 5 feet (152 cm). For these patients, IBW is typically calculated as: males 50 kg, females 45.5 kg, with no height-based addition.

Is this IBW calculator free?

Yes — completely free, no sign-up required. Results export to CSV or print as PDF.

Medical › Body Metrics

Ideal Body Weight Calculator

Calculate ideal body weight (IBW) using four validated clinical formulas — Devine, Robinson, Miller, and Hamwi. Includes adjusted body weight (ABW) for obese patients, BMI-based healthy range, and weight status relative to your actual weight.

🏋️ Calculate Ideal Body Weight

Biological Sex

Age (years, optional)

Height (cm)

Actual Weight (kg, optional)

Advertisement — 468×60

Ideal Body Weight (Devine)

—

Your Weight vs Healthy Range

UnderweightHealthyOverweightObese

All Formulas Compared

Advertisement — 970×90

You May Also Need

⚖️

BMI Calculator

Compare IBW with your BMI classification.

🔥

Calorie Calculator

Set calorie targets to reach your ideal weight.

📏

Body Fat % Calculator

Assess body composition alongside ideal weight.

⚡

BMR Calculator

Calculate metabolic rate for your IBW target.

Advertisement — 970×90

Ideal Body Weight Formulas — Clinical Reference

Ideal body weight (IBW) formulas were originally developed for clinical dosing of medications — particularly weight-sensitive drugs where actual body weight (ABW) may lead to overdose in obese patients. They are also used to set weight management targets and assess body composition. Four formulas are widely used in clinical practice.

Devine Formula (1974) — Most Widely Used

Males: IBW (kg) = 50 + 2.3 × (height in inches − 60)
Females: IBW (kg) = 45.5 + 2.3 × (height in inches − 60)

Robinson Formula (1983)

Males: IBW = 52 + 1.9 × (height in inches − 60)
Females: IBW = 49 + 1.7 × (height in inches − 60)

Miller Formula (1983)

Males: IBW = 56.2 + 1.41 × (height in inches − 60)
Females: IBW = 53.1 + 1.36 × (height in inches − 60)

Hamwi Formula (1964)

Males: IBW = 48 + 2.7 × (height in inches − 60)
Females: IBW = 45.5 + 2.2 × (height in inches − 60)

Adjusted Body Weight (ABW)

When actual body weight exceeds IBW by more than 20%, adjusted body weight is used for drug dosing: ABW = IBW + 0.4 × (ABW − IBW). This accounts for the increased distribution volume in obese patients without using the full actual weight.

Pair IBW with our BMI calculator, calorie calculator, and BMR calculator for a complete weight management plan. For drug dosing using IBW or ABW, see our drug dosage calculator.

⚠️ IBW formulas are clinical reference tools, not definitive targets. Individual healthy weight varies by frame size, muscle mass, and age. Consult a healthcare professional for personalised weight management advice.