Respiratory

Predicted Body Weight (PBW) Calculator

Weight predicted from height and sex, the basis for lung-protective tidal volumes (6 mL/kg PBW in ARDS).

Reviewed by Alex G, BSN, RN, CEN, CCRN, CMC, NREMT-P · From the Reference tab of the app

Turn on JavaScript to use this calculator, or open it in the web app.

Formula

Male: 50 + 2.3 (height in inches - 60)
Female: 45.5 + 2.3 (height in inches - 60)

Key points

• Calculate tidal volume goals (6 mL/kg PBW) based on PBW, NOT actual body weight, to prevent volutrauma/barotrauma in ARDS.

Same formula as the app. Open it in the web app.

Related one-pagers

• Ventilator Modes and SettingsPBW: men 50 kg, women 45.5 kg, + 2.3 kg per inch over 5 feet
• ABG Interpretation in 6 StepsPaCO₂ varies inversely with alveolar ventilation. With CO₂ production and dead space constant, new rate = current rate × current PaCO₂ ÷ target PaCO₂: rate 14, PaCO₂ 60, target 45 gives about 19. Lung-protective ventilation keeps VT at 4–8 mL/kg predicted body weight with plateau 30 cm H₂O or less (ARDSNet 2000: 6 vs 12 mL/kg, mortality 31.0% vs 39.8%), so rate is the usual lever, up to 35. Change one setting at a time and recheck.
• ARDSPBW: men 50 kg, women 45.5 kg, + 2.3 kg per inch over 5 feet.
• Ventilator Liberation and TracheostomyBreathing · RR >35 or <8; SpO₂ <88–90%; Vt <4 mL/kg PBW; pH <7.30

Related calculators

• A-a Gradient
• Alveolar Gas Equation (PAO₂)
• Arterial Oxygen Content (CaO₂)
• Dead Space Fraction (Bohr)
• Driving Pressure
• Dynamic Compliance
• Minute Ventilation
• O₂ Extraction Ratio

For education and exam preparation only. Follow your institution’s protocols. For education and exam preparation only. Verify results independently and follow your institution’s protocols. Not a substitute for clinical judgment.