Convert Centimeters of Water to Millibars

Convert Centimeters of Water (cmH₂O) to Millibars (mbar) instantly and accurately.

Centimeters of Water (cmH₂O)
Millibars (mbar)

Conversion Formula

mbar = cmH₂O × 0.980665

About Centimeters of Water

One centimetre of water column (cmH₂O) ≈ 98.07 Pa - the clinical pressure unit for respiratory and intravascular measurements. Mechanical ventilator settings are in cmH₂O: peak inspiratory pressure (PIP) 15-30 cmH₂O; PEEP 5-15 cmH₂O; plateau pressure should stay below 30 cmH₂O to avoid lung injury. Lumbar puncture CSF opening pressure is normally 8-20 cmH₂O. CPAP/BiPAP therapy for sleep apnea: 4-20 cmH₂O. Central venous pressure is also reported in cmH₂O. 1 cmH₂O = 98.0665 Pa.

About Millibars

A millibar (mbar) = 100 Pa = 1 hPa - the historically dominant meteorological pressure unit. Standard sea-level pressure is 1013.25 mbar. Hurricane intensity is characterised by central pressure: Category 5 storms typically below 920 mbar (US record: 892 mbar, 1935). Upper-air analysis levels - 850, 700, 500, 300, 200 mbar - appear throughout decades of archived meteorological data. Aircraft cabins are pressurised to ~750-800 mbar at cruise altitude. 'Weather bombs' see pressure fall 24+ mbar in 24 hours. 1 mbar = 100 Pa.

Quick Reference Table

Centimeters of Water (cmH₂O)Millibars (mbar)
1 cmH₂O0.980665 mbar
2 cmH₂O1.96133 mbar
5 cmH₂O4.90332 mbar
10 cmH₂O9.80665 mbar
25 cmH₂O24.5166 mbar
50 cmH₂O49.0333 mbar
100 cmH₂O98.0665 mbar

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