How this calculator works
The cited ARDSNet protocol gives predicted body weight as 50 + 2.3 x (height in inches - 60) for males and 45.5 + 2.3 x (height in inches - 60) for females. This page uses those inch-based equations consistently after converting the height. It multiplies predicted weight by the stated mL/kg factor and also shows 4, 6 and 8 mL/kg references. Actual ventilation depends on pressures, gas exchange, respiratory mechanics and the treating team's protocol. The result is an estimate for information only and is not medical advice.
Formula
PBW male (kg) = 50 + 2.3 x (height in inches - 60). PBW female (kg) = 45.5 + 2.3 x (height in inches - 60). Tidal volume (mL) = PBW x stated mL/kg factor. Height (inches) = (volume/factor - intercept)/2.3 + 60.
Worked example
At 70 inches, male PBW = 50 + 2.3 x 10 = 73 kg. The 4, 6 and 8 mL/kg reference volumes are 292, 438 and 584 mL. At 60 inches, female PBW is 45.5 kg and the 6 mL/kg reference is 273 mL.
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Frequently asked questions
Why not use actual body weight?
The protocol uses height and sex to estimate lung size. Actual body weight, especially with excess adipose tissue, does not scale directly with lung volume.
Are these ventilator prescriptions?
No. These are formula references for trained clinicians. Volume targets and changes require the full bedside protocol and monitoring.
Does the inverse mode recommend a height or volume?
No. It only shows the height implied by a stated volume and factor. It cannot validate a patient's ventilation plan.