Tidal Volume Calculator

About this calculator

Tidal volume is the amount of air moved in a single breath, and in mechanical ventilation, using too large a tidal volume can overstretch and injure the lungs — a problem especially critical in patients with acute respiratory distress syndrome (ARDS). Lung-protective ventilation protocols, most notably the ARDSnet strategy, target roughly 6 to 8 mL per kilogram of ideal body weight (IBW), not actual body weight, since lung size correlates with height and sex rather than with fat mass.

Ideal body weight is estimated from height and sex using formulas such as the Devine formula, and the tidal volume target is then derived from that IBW rather than the patient's measured weight — meaning an obese patient and a lean patient of the same height receive the same target tidal volume. This calculator takes height and sex, estimates ideal body weight, and returns the 6 to 8 mL/kg tidal volume range clinicians use to set protective ventilator settings.