Calculate static compliance (Cstat) and driving pressure from tidal volume, plateau pressure, and total PEEP. The calculator keeps measurement quality visible because a precise-looking result can still be unreliable when the inspiratory hold, patient effort, auto-PEEP, or leak is not accounted for.
Core equations
Cstat = VT ÷ (Pplat − PEEPtotal)
Driving pressure = Pplat − PEEPtotal
Enter values obtained at approximately the same ventilator conditions and time point.
With a tidal volume of 450 mL, plateau pressure of 25 cm H₂O, and total PEEP of 10 cm H₂O:
This is respiratory-system compliance, so the result reflects the combined mechanical behavior of the lungs and chest wall.
Plateau pressure is measured during an end-inspiratory occlusion after flow reaches zero. A leak, continued flow, active inspiratory or expiratory effort, or an unstable maneuver can make the apparent plateau misleading.
Use your ventilator's validated measurement workflow and local protocol. The calculator does not determine whether the maneuver itself was valid.
The elastic pressure change is plateau pressure minus total PEEP. Total PEEP includes the PEEP set on the ventilator plus intrinsic PEEP that remains at end expiration.
If you enter measured total PEEP, do not add auto-PEEP a second time. If you use the component mode, enter set PEEP and measured auto-PEEP separately.
Static compliance uses plateau pressure during no flow and focuses on elastic load. Dynamic compliance uses peak inspiratory pressure during flow and therefore reflects both elastic and airway-resistive pressure.
A change in peak pressure without a similar change in plateau pressure points toward a resistive contribution; interpret waveforms and the full bedside assessment.
Body habitus, position, chest-wall mechanics, recruited lung volume, ventilator settings, and technique can all change Cstat. A repeatable trend under comparable conditions is usually more interpretable than a single value.
Reduced compliance may accompany edema, ARDS, atelectasis, pneumonia, pneumothorax, low lung volume, increased abdominal or chest-wall load, or a flawed pressure measurement. Cstat alone does not identify the cause.
Static respiratory system compliance is tidal volume divided by the difference between plateau pressure and total PEEP: Cstat = VT / (Pplat − PEEPtotal). Tidal volume is expressed in mL and the result in mL/cm H2O.
Use total PEEP when available because it includes intrinsic PEEP. If total PEEP is not displayed directly, add measured auto-PEEP to set PEEP. Do not add auto-PEEP again when entering a measured total PEEP.
There is no single universal bedside cutoff that is appropriate for every patient. Reviews commonly cite adult respiratory-system compliance values beginning around 50 mL/cm H2O, with ranges such as 50–70 or 50–100 mL/cm H2O. Values substantially below 50 therefore appear reduced, but body habitus, chest-wall mechanics, lung volume, position, measurement technique, and disease all affect the result.
Yes. Patient effort can distort plateau pressure and make the calculated compliance unreliable. Interpret the result only when the pressure measurement reflects a valid no-flow condition without meaningful patient effort or leak.
Static compliance uses plateau pressure measured during a no-flow pause and primarily reflects the elastic behavior of the respiratory system. Dynamic compliance uses peak inspiratory pressure during flow and is affected by both elastic and airway-resistive pressure.
For education and clinical support only. This tool does not replace validated ventilator measurement technique, local protocols, or clinician assessment, and it does not diagnose the cause of altered respiratory mechanics. No entered values are stored.