Health, Medical & SportsPBW (Male) = 50 + 0.91 × (Height_cm - 152.4)

Tidal Volume Calculator (ARDSNet)

Calculate lung-protective mechanical ventilation tidal volumes (4-8 mL/kg) based on Ideal Body Weight (IBW) derived from ARDSNet guidelines.

Tidal Volume & PBW Solver

ARDSNet protocol • 4, 6, 8 mL/kg • Minute ventilation

Presets:

1. Patient Demographics

Biological Sex

MaleFemale

Patient Height

Respiratory Rate (RR)

bpm

2. Predicted Body Weight (PBW)Clinical Standard

Ideal Lung Weight

73.3 kg (161.6 lbs)

3. Target Tidal Volume Targets (V_T)

Standard ARDSNet Target (6 mL/kg)Recommended initial lung-protective ventilation

440 mLV_E: 7.0 L/min

Ultra-Protective (4 mL/kg)Severe ARDS with elevated plateau pressures

293 mLV_E: 4.7 L/min

Acceptable Range (8 mL/kg)Upper boundary for non-ARDS patients

586 mLV_E: 9.4 L/min

Formulas, calculation steps & FAQs below↓

Formulas & Calculation Guide

Clinical Principles of Lung-Protective Mechanical Ventilation

Prior to the year 2000, intensive care units routinely ventilated patients with acute respiratory failure at high tidal volumes (10–15 mL/kg). In 2000, the Acute Respiratory Distress Syndrome Network (ARDSNet) published the landmark ARMA trial in the New England Journal of Medicine, establishing that lower tidal volume ventilation targeting 6 mL/kg PBW dramatically decreases mortality and increases ventilator-free days.

Predicted Body Weight (PBW) Formulas

Because thoracic dimensions correlate with skeletal height rather than body mass index (BMI):

Males (cm): PBW (kg) = 50 + 0.91 × (Height in cm - 152.4)
Males (inches): PBW (kg) = 50 + 2.3 × (Height in inches - 60)
Females (cm): PBW (kg) = 45.5 + 0.91 × (Height in cm - 152.4)
Females (inches): PBW (kg) = 45.5 + 2.3 × (Height in inches - 60)

Ventilator setting – calculation example

Let’s see an example calculation for an adult male measuring 5 ft 10 in (70 inches / 178 cm):

Select patient sex: sex = Male.
Enter patient height: height = 70 inches (178 cm).
The calculation results are available for you: Predicted Body Weight (PBW) = 73.0 kg.
Initial ARDSNet protective target: 6 mL/kg PBW = 438 mL.
Safe protective range: 4 to 8 mL/kg PBW = 292 to 584 mL.

💡 Ventilator tidal volumes should always be calibrated to PBW (lung size) rather than actual total weight to avoid barotrauma in patients with elevated BMI.

Ventilator Target Ranges by Clinical Protocol

Setting	Formula Target	Clinical Context
Initial ARDS Target	6 mL/kg PBW	Standard lung-protective target for acute lung injury and general ICU ventilation.
Severe ARDS / High Plateau	4 – 5 mL/kg PBW	Used when plateau pressure (P_plat) exceeds 30 cm H₂O or driving pressure is elevated.
Weaning / Normal Compliance	7 – 8 mL/kg PBW	Mild recovery phase, spontaneous breathing trials, or patients without parenchymal lung injury.

Clinical Note: This tool is intended for medical education and reference. Ventilator settings must always be individualized based on arterial blood gas (ABG) values, plateau airway pressures, and patient clinical status.

Frequently Asked Questions

Expert answers to common calculations, unit conversions, and dimensional requirements.

Why must ventilator tidal volume be based on Predicted Body Weight (PBW) instead of actual weight?↓

Normal human lung size is determined almost exclusively by skeletal height and biological sex, not by body fat or obesity. An obese patient weighing 140 kg has the same lung volume as a lean patient of the same height weighing 70 kg. Ventilating based on actual weight delivers massive excessive volume (volutrauma), causing alveolar rupture and worsened mortality.

What is the standard ARDSNet lung-protective tidal volume target?↓

The landmark ARDS Network (ARMA trial) demonstrated that lower tidal volume ventilation targeting 6 mL/kg of Predicted Body Weight (PBW) reduced mortality by 22% compared to traditional 12 mL/kg ventilation. In severe ARDS or low lung compliance, tidal volume is often titrated down to 4–5 mL/kg.

What is the formula for Predicted Body Weight (PBW)?↓

The Devine formula modified by ARDSNet: Males: PBW (kg) = 50 + 0.91 · (Height in cm - 152.4). Females: PBW (kg) = 45.5 + 0.91 · (Height in cm - 152.4). In inches: Males: 50 + 2.3 · (Height in inches - 60); Females: 45.5 + 2.3 · (Height in inches - 60).

What is normal resting tidal volume in an unventilated healthy adult?↓

A healthy resting adult breathes at roughly 500 mL per breath (approximately 6 to 8 mL/kg PBW) at a respiratory rate of 12 to 16 breaths per minute, producing a minute ventilation of approximately 6 to 8 liters per minute.