Pounds per Square Inch (psi) Conversion Tool - Convert psi to Any Unit
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psi Conversion Table
This comprehensive psi conversion table shows how various units relate to pounds per square inch, a common unit for pressure measurement. Use this reference for quick conversions between psi and other pressure units.
| Conversion | To Unit | Multiplier |
|---|---|---|
| psi to pascals | Pascals | 6894.76 |
| psi to kilopascals | Kilopascals | 6.89476 |
| psi to bars | Bars | 0.0689476 |
| psi to millibars | Millibars | 68.9476 |
| psi to atmospheres | Atmospheres | 0.068046 |
| psi to torr | Torr | 51.7149 |
| psi to cmH₂O | Centimeters of Water | 70.307 |
| psi to inHg | Inches of Mercury | 2.03602 |
This psi conversion reference table provides accurate conversion factors for both metric and imperial pressure units. All values are based on internationally recognized standards for maximum precision in scientific and engineering applications.
What is Pounds per Square Inch (psi)?
Pounds per square inch (symbol: psi) is a unit of pressure based on the avoirdupois system. It is defined as the pressure resulting from a force of one pound-force applied to an area of one square inch. This makes psi equal to approximately 6,894.76 pascals (the SI unit for pressure).
Psi is commonly used in the United States for measuring pressure in various applications, including tire pressure, scuba tank pressure, and industrial systems. Our psi conversion tool helps you easily convert between psi and other pressure units. For example, 1 psi equals approximately 0.06895 bars or 51.715 torr.
What is the SI of Pounds per Square Inch?
Pounds per square inch (psi) is not an SI unit. The SI unit for pressure is the pascal (Pa), which is defined as one newton per square meter (N/m²). However, psi is widely used in the United States and other countries that use the imperial system. All pressure units can be converted to the SI base unit for pressure conversion:
- 1 psi = 6,894.76 pascals
- 1 psi = 6.89476 kilopascals
- 1 psi = 0.0689476 bars
- 1 psi = 0.068046 atmospheres
- 1 psi = 51.7149 torr
What is psi Used For?
Pounds per square inch (psi) is used in a wide range of applications across engineering, automotive, industrial, and everyday contexts. Though not an SI unit, psi is the standard pressure measurement in the United States for pressure conversion:
Automotive Industry
Tire pressure specifications, fuel system pressure, and engine compression ratios. For example, typical car tire pressure ranges from 32 to 35 psi.
Industrial Systems
Hydraulic systems, pneumatic equipment, and process control. For example, industrial air compressors often operate at pressures between 100 and 150 psi.
Engineering Applications
Structural analysis, material testing, and mechanical design. For example, determining that a pipe rated for 150 psi can withstand approximately 1,034,214 pascals.
Medical Equipment
Blood pressure measurements and respiratory equipment. For example, normal blood pressure is around 120/80 mmHg, which is approximately 2.32/1.55 psi.
Etymology and History
The term "pounds per square inch" comes from combining the imperial unit of force (pound) with the unit of area (square inch). The pound-force used in psi is defined as the gravitational force exerted on a mass of one avoirdupois pound on the surface of Earth. This definition makes psi a convenient unit for practical engineering applications in countries using the imperial system.
Although psi is not part of the International System of Units (SI), it remains widely used in the United States and other countries that have not fully adopted the metric system. The SI unit for pressure, the pascal, is increasingly used in scientific contexts globally, even in the U.S., making pressure conversion between psi and pascals essential for international collaboration.
Frequently Asked Questions
Why is psi used instead of SI units?
Psi is used primarily in the United States due to historical adoption of the imperial system. While the SI unit for pressure is the pascal (Pa), psi remains the standard for many practical applications like tire pressure and industrial systems in the U.S. This is why pressure conversion between psi and SI units is important for international work.
How accurate is the psi definition?
The definition of psi is quite precise as it's based on the pound-force and the square inch, both of which have exact definitions. 1 psi equals exactly 6,894.757293168361 pascals. This makes pressure conversion from psi to SI units highly accurate when using the correct conversion factor.
What's the difference between psia and psig?
Psia (pounds per square inch absolute) measures pressure relative to a perfect vacuum, while psig (pounds per square inch gauge) measures pressure relative to atmospheric pressure. For example, if a tire pressure gauge reads 32 psi, that's 32 psig, but the absolute pressure (psia) would be about 46.7 psi (32 + 14.7 atm).
How do I convert psi to other units?
Use our psi conversion calculators above, or multiply by the appropriate conversion factor. For example, to convert psi to pascals, multiply by 6,894.76; to convert psi to bars, multiply by 0.06895. For detailed instructions on converting psi to pascals, visit our psi to Pa converter.
What are common uses for psi conversion?
Psi conversion is essential in automotive maintenance (tire pressure), engineering projects (hydraulic systems), industrial processes (pneumatic equipment), and scientific research. Whether calculating scuba tank pressure or converting engineering specifications, our psi converter tool simplifies these everyday tasks.
How does psi conversion differ from other pressure units?
Unlike SI units which are based on meters and newtons, psi is based on inches and pounds, reflecting the imperial system. This makes pressure conversion between psi and SI units necessary for international work. The relationship between psi and other imperial units is straightforward, but conversion to metric requires specific factors.
Can I convert very high or low pressures in psi?
Yes, our psi converter handles both extremely high and low pressures with precision. For vacuum work, convert micropascals to psi (1 μPa = 1.45038e-10 psi). For high-pressure applications, convert psi to megapascals (1 psi ≈ 0.006895 MPa). Our smart rounding feature ensures readable results for all scales.
Is your psi conversion tool free to use?
Yes, our psi conversion calculator is completely free with no registration required. Simply enter your value, select your target unit, and get instant, accurate results. We believe precise pressure conversion should be accessible to everyone, from automotive enthusiasts checking tire pressure to engineers working on complex hydraulic systems.