Convert Feet of Water to Millibars
Convert Feet of Water (ftH₂O) to Millibars (mbar) instantly and accurately.
Conversion Formula
mbar = ftH₂O × 29.8906692
About Feet of Water
One foot of water column (ftH₂O) ≈ 2,989 Pa - the US customary equivalent of cmH₂O used in civil and hydraulic engineering. Municipal water supply systems are designed for 40-80 psi head ≈ 92-184 ft; fire suppression sprinkler systems require minimum 7 psi ≈ 16 ft. Well pump specifications, sump pump head ratings, irrigation mainline pressure, and drainage calculations all use feet of head. 1 ft of water = 12 in WC = 0.4335 psi ≈ 2,989 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
| Feet of Water (ftH₂O) | Millibars (mbar) |
|---|---|
| 1 ftH₂O | 29.8907 mbar |
| 2 ftH₂O | 59.7813 mbar |
| 5 ftH₂O | 149.453 mbar |
| 10 ftH₂O | 298.907 mbar |
| 25 ftH₂O | 747.267 mbar |
| 50 ftH₂O | 1494.53 mbar |
| 100 ftH₂O | 2989.07 mbar |