Tidal Volume Calculator
Tidal volume for mechanical ventilation should be based on ideal body weight, not actual body weight. This calculator uses the Devine formula to estimate ideal body weight from height and sex, then calculates the tidal volume at your target mL/kg setting.
The ARDSNet trial demonstrated that lower tidal volumes (6 mL/kg of ideal body weight) reduce mortality in patients with acute respiratory distress syndrome compared to traditional volumes of 12 mL/kg. Today, lung-protective ventilation using 6 to 8 mL/kg of IBW is standard practice for most mechanically ventilated patients, not just those with ARDS.
Ideal body weight is calculated using the Devine formula: for males, IBW = 50 + 2.3 x (height in inches - 60); for females, IBW = 45.5 + 2.3 x (height in inches - 60). This formula was originally designed for drug dosing but has become the standard for ventilator settings because lung size correlates more closely with height than with actual body weight.
Using actual body weight for tidal volume calculations in obese patients leads to overdistension and ventilator-induced lung injury. A 5'4" woman has the same lung capacity regardless of whether she weighs 130 or 250 pounds, so her tidal volume should be the same. Always use predicted or ideal body weight for ventilator settings.