PSI to Pounds Per Square Foot (psi to psf)
1 pound per square inch equals 144 pounds per square foot exactly.
How to convert pounds per square inch to pounds per square foot
To convert pounds per square inch to pounds per square foot, multiply the number of pounds per square inch by 144. This factor is exact. To go the other way, multiply pounds per square foot by 0.006944444444 (rounded).
pounds per square foot = pounds per square inch × 144
Example: 10 pounds per square inch = 1,440 pounds per square foot.
About these units
Pound Per Square Inch (psi)
About 6,894.757 pascals. The common unit for tire pressure, hydraulics and gas pipelines in the US.
Unlike most pressure units, psi has no namesake: it simply spells out its own definition, one pound-force acting on one square inch, and it is based on avoirdupois units. Used mainly in the United States, it is about 6.895 kilopascals.
The letters after the unit matter. Psia is measured against a vacuum, while psig is measured against the surrounding air, so at sea level, where the atmosphere is about 14.7 psi, you add that amount to a gauge reading to get an absolute one. A bicycle tire at 65 psig is therefore at 79.7 psia, and the label psid means a difference between two pressures rather than a reference to ambient air.
Typical automobile tires are listed at about 32 psig, and road racing bicycle tires at about 120 psig. One standard atmosphere is 14.696 psi, which gives a feel for how many multiples of sea-level air those tire pressures represent.
1 pound per square inch = 6,894.757293 pascals (approximately).
Sources: Wikipedia: Pounds per square inch; Wikipedia: Standard atmosphere (unit)
Pound Per Square Foot (psf)
About 47.88 pascals. Used in US structural engineering for distributed loads.
A square foot is 144 square inches, so one pound per square foot is one 144th of a psi, which comes to about 47.88 Pa; NIST gives 47.88026. The number is easy to picture: spread one pound-force evenly over a floor tile a foot across and that is the pressure, tiny compared with the 101,325 Pa of one standard atmosphere.
Building codes in the United States commonly state loads on floors and roofs this way, and snow and wind pressures are tabulated in the same unit. Metric countries use kilopascals or newtons per square metre instead, and 1 kPa is about 20.9 psf. Multiplying a psf figure by 144 gives psi, and by 47.88 gives pascals, so a 40 psf floor load is about 1.9 kPa.
1 pound per square foot = 47.88025898 pascals (approximately).
Sources: NIST SP 811, Appendix B.8; Wikipedia: Pounds per square inch
Related conversions
- Pounds per square foot to PSI (reverse)
- PSI to pascals
- PSI to kilopascals
- PSI to bars
- PSI to standard atmospheres
- PSI to hectopascals
- PSI to megapascals
- PSI to millibars
- PSI to torr
- PSI to millimeters of mercury
- PSI to inches of mercury
- PSI to gigapascals
- PSI to kilopounds per square inch
- Pascals to pounds per square foot
- Kilopascals to pounds per square foot
- Bars to pounds per square foot
- Standard atmospheres to pounds per square foot
See all pressure units.