Convert Inches of Mercury to Pounds per Square Inch
Convert Inches of Mercury (inHg) to Pounds per Square Inch (psi) instantly and accurately.
Conversion Formula
psi = inHg × 0.4911541475
About Inches of Mercury
One inch of mercury (inHg) ≈ 3,386 Pa - the primary barometric pressure unit in US aviation and meteorology. ASOS weather stations, METARs, and altimeter settings in the US report in inHg. Standard sea-level pressure is 29.92 inHg. Altimeters are set to local QNH in inHg to maintain altitude reference. US barometers for home weather stations display inHg. Typical pressure range: 28.5-31.0 inHg in continental weather systems. Record low: ~25.70 inHg (Typhoon Tip, 1979). 1 inHg = 3,386.39 Pa.
About Pounds per Square Inch
One pound per square inch (psi) ≈ 6,894.76 Pa - the dominant pressure unit in US industry and consumer products. Car tyres: 32-36 psi; truck tyres 80-120 psi; bicycle road tyres 80-130 psi. Home water supply: 40-80 psi; residential maximum 80 psi per plumbing code. Compressed air tools: 90-150 psi. Steam autoclave sterilisation: 15-30 psi. The distinction between gauge (psig) and absolute (psia) pressure is critical: gauge pressure is relative to ambient; absolute = gauge + ~14.696 psi. 1 psi = 6,894.76 Pa.
Quick Reference Table
| Inches of Mercury (inHg) | Pounds per Square Inch (psi) |
|---|---|
| 1 inHg | 0.491154 psi |
| 2 inHg | 0.982308 psi |
| 5 inHg | 2.45577 psi |
| 10 inHg | 4.91154 psi |
| 25 inHg | 12.2789 psi |
| 50 inHg | 24.5577 psi |
| 100 inHg | 49.1154 psi |