# Pounds per square inch

**psilb f /in 2 psiglbf/in²ksipounds-force per square inchpsiap.s.i.pound per square inchlbf/in 2**

The pound per square inch or, more accurately, pound-force per square inch (symbol: lbf/in 2 ; abbreviation: psi) is a unit of pressure or of stress based on avoirdupois units.wikipedia

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### Atmospheric pressure

**barometric pressureair pressurepressure**

The standard atmosphere (symbol: atm) is a unit of pressure defined as 101325 Pa, equivalent to 760mm Hg, 29.9212inchesHg, or 14.696psi.

### Pound (force)

**lbflb f pound-force**

It is the pressure resulting from a force of one pound-force applied to an area of one square inch.

### Inch of water

**inches of waterinH 2 Oin H 2 O**

This is in contrast to inches of mercury or pounds per square inch (psi, lbf/in) for larger pressures.

### Pressure

**water pressurenegative pressurefluid pressure**

The pound per square inch or, more accurately, pound-force per square inch (symbol: lbf/in 2 ; abbreviation: psi) is a unit of pressure or of stress based on avoirdupois units.

Some of these derive from a unit of force divided by a unit of area; the SI unit of pressure, the pascal (Pa), for example, is one newton per square metre (N/m 2 ); similarly, the pound-force per square inch (psi) is the traditional unit of pressure in the imperial and US customary systems.

### Pressure measurement

**manometerpressure gaugegauge pressure**

A vacuum gauge is a pressure gauge used to measure pressures lower than the ambient atmospheric pressure, which is set as the zero point, in negative values (e.g.: −15 psig or −760 mmHg equals total vacuum).

### Ultimate tensile strength

**tensile strengthtensileultimate strength**

They are mostly used in materials science, where the tensile strength of a material is measured as a large number of psi.

A United States customary unit is pounds per square inch (lb/in² or psi), or kilo-pounds per square inch (ksi, or sometimes kpsi), which is equal to 1000 psi; kilo-pounds per square inch are commonly used in one country (US), when measuring tensile strengths.

### Millimetre of mercury

**mmHgmm Hgmillimetres of mercury**

### Pascal (unit)

**hPaMPakPa**

The pascal (Pa) or kilopascal (kPa) as a unit of pressure measurement is widely used throughout the world and has largely replaced the pounds per square inch (psi) unit, except in some countries that still use the imperial measurement system or the US customary system, including the United States.

### Conversion of units

**conversion factorunit conversionConversions**

### United States customary units

**USUS customary unitsU.S. customary units**

### Avoirdupois system

**avoirdupoislbavoirdupois ounce**

The pound per square inch or, more accurately, pound-force per square inch (symbol: lbf/in 2 ; abbreviation: psi) is a unit of pressure or of stress based on avoirdupois units.

### Square inch

**in 2 in²inches square**

It is the pressure resulting from a force of one pound-force applied to an area of one square inch.

### International System of Units

**SISI unitsSI unit**

In SI units, 1 psi is approximately equal to 6895 N/m 2.

### Newton (unit)

**kNnewtonN**

In SI units, 1 psi is approximately equal to 6895 N/m 2.

### Square metre

**m 2 square meterm²**

In SI units, 1 psi is approximately equal to 6895 N/m 2.

### Vacuum

**free spaceevacuatedhigh vacuum**

Pounds per square inch absolute (psia) is used to make it clear that the pressure is relative to a vacuum rather than the ambient atmospheric pressure.

### Sea level

**mean sea levelMSLAMSL**

Since atmospheric pressure at sea level is around 14.7 psi, this will be added to any pressure reading made in air at sea level.

### Materials science

**material sciencematerials engineeringmaterials scientist**

They are mostly used in materials science, where the tensile strength of a material is measured as a large number of psi.

### Mechanics

**mechanicaltheoretical mechanicsmechanician**

It is used in mechanics for the elastic modulus of materials, especially for metals.

### Elastic modulus

**modulus of elasticityelastic modulimodulus**

It is used in mechanics for the elastic modulus of materials, especially for metals.

### Blood pressure

**systolic blood pressurediastolic blood pressurearterial blood pressure**