What is a good PSI for car tires?

Standard car tire pressure : 32-35 PSI (when cold) Always check your specific vehicle : Driver's door jamb sticker (most reliable) Owner's manual Fuel filler door (some vehicles) By vehicle type : Compact cars: 30-33 PSI Sedans: 32-35 PSI SUVs/Light trucks: 35-45 PSI High-performance: 36-40 PSI Important : Check when tires are COLD (before driving). Tire pressure increases 4-6 PSI after driving. Convert to your region: PSI to Bar →

How do I convert PSI to bar?

Formula : Bar = PSI × 0.0689476 (or divide PSI by 14.5) Examples : 10 PSI = 0.69 bar 30 PSI = 2.07 bar 50 PSI = 3.45 bar 100 PSI = 6.89 bar Quick mental math : Divide PSI by 14.5 or 15 30 PSI ÷ 15 ≈ 2 bar (actual: 2.07) Use our PSI to Bar converter →

What does PSIG vs PSIA mean?

PSIG (Pounds per Square Inch Gauge) : Pressure relative to atmospheric pressure 0 PSIG = atmospheric pressure (14.7 PSIA at sea level) What most pressure gauges show Used for tires, compressors, hydraulics PSIA (Pounds per Square Inch Absolute) : Pressure relative to perfect vacuum 0 PSIA = absolute vacuum 14.7 PSIA = atmospheric pressure at sea level Used in scientific/engineering calculations Conversion : PSIA = PSIG + 14.7 (at sea level) Example : 32 PSIG tire pressure = 46.7 PSIA total pressure

What is 100 PSI in bar and kPa?

100 PSI equals : 6.89 bar 689.5 kPa (kilopascals) 0.689 MPa (megapascals) Quick conversions : 100 PSI to Bar → 100 PSI to kPa → Context : 100 PSI is typical for: Heavy-duty air compressor output Semi-truck tire pressure Pneumatic tool operating pressure

Is 40 PSI good tire pressure?

40 PSI can be correct depending on your vehicle : Good for : Large SUVs and trucks Some high-performance vehicles Vehicles when fully loaded Too high for : Most passenger cars (typically 32-35 PSI) Compact cars (typically 30-33 PSI) How to know : Check driver's door jamb sticker Consult owner's manual Never rely on tire sidewall (that's MAX pressure) Effects of overinflation : Harsher ride Reduced traction Uneven tire wear (center wears faster) Always check : When tires are COLD, before driving.

How many PSI in 1 atmosphere?

1 atmosphere (atm) = 14.6959 PSI (approximately 14.7 PSI) Standard atmospheric pressure at sea level : 14.696 PSI (PSIA) 101.325 kPa 1.01325 bar 760 mmHg / 760 Torr 29.92 inHg Altitude effects : Sea level: 14.7 PSI Denver (5,280 ft): ~12.1 PSI 10,000 ft: ~10.1 PSI Convert Atmosphere to PSI →

What PSI should I set my air compressor to?

Typical settings : General Shop Use : 90-100 PSI Most pneumatic tools operate best at 90 PSI Allows for pressure drop in hoses Specific Applications : Impact wrench: 90 PSI Nail gun: 70-120 PSI (tool dependent) Paint sprayer: 25-50 PSI Tire inflation: 30-40 PSI Sandblasting: 80-100 PSI Air brush: 15-30 PSI Compressor tank pressure : 125-150 PSI (maximum) Compressor cuts off at max (e.g., 135 PSI) Compressor cuts on when drops (e.g., 100 PSI) Set regulator to desired tool pressure (e.g., 90 PSI) Pro tip : Set higher tank pressure, use regulator for precise tool pressure.

Why is PSI used instead of bar in the US?

Historical reasons : Imperial system was established before metric US industry standardized on PSI in early 1900s Extensive infrastructure built around imperial units Practical resistance to change : All existing gauges, equipment use PSI Workforce trained in PSI Replacement costs would be enormous Cultural familiarity Current situation : US is primary country still using PSI Scientific/international work uses metric (bar, kPa) Some US industries use both systems For travelers : Most modern tire gauges show both PSI and bar. Convert between systems: PSI to Bar →

Pound per Square Inch (psi) - Unit Information & Conversion

Symbol:psi

Plural:pounds per square inch

Category:Pressure

🔄 Quick Convert Pound per Square Inch

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What is a Pound per Square Inch?

PSI (pounds per square inch) is the standard pressure unit in the United States, measuring force in pounds over one square inch of area. Widely used for tire pressure, air compressors, hydraulics, pneumatic tools, plumbing, and HVAC systems.

History of the Pound per Square Inch

Derived from imperial units of pound-force and inch. Became standard in US industry and automotive applications in the early 20th century. Despite global metric adoption, PSI remains dominant in American manufacturing, construction, and automotive industries.

Quick Answer

What is PSI? PSI (pounds per square inch) measures pressure as pounds of force applied over one square inch. It's the standard pressure unit in the US for automotive tire pressure, air compressors, hydraulics, and plumbing. Typical car tire pressure is 32-35 PSI. Use our pressure converter to convert PSI to bar, kPa, atmospheres, and other units instantly.

Quick Comparison Table

PSI	Bar	kPa	Context	Convert Now
14.7	1.01	101.3	Standard atmospheric pressure	PSI to Bar →
30	2.07	206.8	Bike tire pressure	PSI to kPa →
32-35	2.2-2.4	220-240	Car tire pressure	PSI to Bar →
50	3.45	344.7	Truck tire pressure	PSI to kPa →
90-120	6.2-8.3	620-827	Air compressor, pneumatic tools	PSI to Bar →
2000+	138+	13,790+	Hydraulic systems	PSI to MPa →

Need a different conversion? Try our pressure converter for all pressure units.

Definition

PSI (pounds per square inch) is a unit of pressure expressing force in pounds-force distributed over an area of one square inch. One PSI equals approximately 6,894.76 Pascals or 0.0689 bar.

Key conversions:

1 PSI = 6,894.76 Pa (Pascals)
1 PSI = 6.895 kPa (Kilopascals)
1 PSI = 0.0689 bar
14.7 PSI = 1 atmosphere (atm)
Convert instantly with our PSI to bar converter

Important distinction:

PSIG (gauge pressure): Relative to atmospheric pressure (0 PSIG = atmospheric)
PSIA (absolute pressure): Relative to perfect vacuum
Most pressure gauges show PSIG

Real-World Examples

Automotive Tire Pressure

Passenger Cars:

Compact cars: 30-33 PSI (cold)
Sedans: 32-35 PSI (standard)
SUVs: 35-40 PSI
High-performance: 36-40 PSI

Trucks & Commercial:

Light trucks: 35-45 PSI
Semi-truck front: 100-120 PSI
Semi-truck rear (loaded): 80-100 PSI

Bicycles:

Road bike: 80-130 PSI
Mountain bike: 25-50 PSI
Hybrid: 50-70 PSI

Convert tire pressure: PSI to Bar →

Air Compressors & Pneumatic Tools

Workshop Equipment:

Pneumatic tools: 90-100 PSI (operating)
Portable air compressor: 125-175 PSI (maximum)
Industrial air compressor: 100-150 PSI (continuous)

Specific Tools:

Impact wrench: 90 PSI
Paint sprayer: 25-50 PSI
Nail gun: 70-120 PSI
Air ratchet: 90 PSI
Sandblaster: 80-100 PSI

Plumbing & Water Systems

Residential:

City water main: 40-80 PSI
Household minimum: 20 PSI
Optimal range: 45-60 PSI
Maximum safe: 80 PSI

Commercial & Industrial:

Fire hydrant: 50-70 PSI
High-rise buildings: 60-100 PSI
Irrigation systems: 30-50 PSI

HVAC & Refrigeration

Air Conditioning (R-410A):

Low side: 118-138 PSI
High side: 250-450 PSI

Heating Systems:

Boiler pressure: 12-15 PSI
Residential gas line: 0.25 PSI

Hydraulic Systems

Mobile Hydraulics:

Car hydraulic jacks: 1,500-2,000 PSI
Construction equipment: 2,500-3,500 PSI
Excavators: 3,000-5,000 PSI

Industrial Hydraulics:

Standard systems: 1,000-3,000 PSI
Heavy industrial: 3,000-5,000 PSI
High-pressure: 10,000+ PSI

Convert hydraulic pressure: PSI to Bar →

Common Uses

Automotive Industry

Primary pressure unit for tire inflation, fuel injection systems, turbo boost pressure, brake systems, and hydraulic lifts throughout North America.

Manufacturing & Industry

Standard for hydraulic presses, pneumatic systems, compressors, pressure vessels, and industrial equipment specifications in the US.

Construction

Used for concrete pumps, hydraulic tools, pneumatic nailing equipment, sandblasting, and compressed air systems.

HVAC & Refrigeration

Universal unit for refrigerant pressures, duct static pressure, gas line pressure, and system diagnostics in US HVAC industry.

Plumbing

Standard for water pressure measurements, pressure regulators, well pumps, and municipal water systems in the United States.

Common Conversion Mistakes to Avoid

❌ Mistake #1: Confusing PSIG and PSIA

Wrong: Assuming 30 PSI tire gauge = 30 PSIA
Correct: 30 PSIG = 44.7 PSIA (add atmospheric 14.7 PSI)
Fix: Most gauges show PSIG (gauge pressure), not absolute

❌ Mistake #2: Wrong PSI to Bar Conversion

Wrong: 30 PSI = 30 bar
Correct: 30 PSI = 2.07 bar (divide by 14.5, not 1)
Tool: PSI to Bar converter

❌ Mistake #3: Reading Tire Placard Wrong

Wrong: Using max PSI from tire sidewall
Correct: Use PSI from door jamb sticker (vehicle-specific)
Note: Tire sidewall shows MAXIMUM safe pressure, not recommended

❌ Mistake #4: Hot vs Cold Tire Pressure

Wrong: Setting pressure while tires are hot
Correct: Check/adjust when cold (before driving)
Reason: Pressure increases 4-6 PSI when tires heat up from driving

Pound per Square Inch Conversion Formulas

To Pascal:

1 psi = 6894.757293 Pa

Example: 5 pounds per square inch = 34473.786466 pascals

To Kilopascal:

1 psi = 6.894757 kPa

Example: 5 pounds per square inch = 34.473786 kilopascals

To Megapascal:

1 psi = 0.006895 MPa

Example: 5 pounds per square inch = 0.034474 megapascals

To Hectopascal:

1 psi = 68.947573 hPa

Example: 5 pounds per square inch = 344.737865 hectopascals

To Bar:

1 psi = 0.068948 bar

Example: 5 pounds per square inch = 0.344738 bars

To Millibar:

1 psi = 68.947573 mbar

Example: 5 pounds per square inch = 344.737865 millibars

To Atmosphere:

1 psi = 0.068046 atm

Example: 5 pounds per square inch = 0.34023 atmospheres

To Technical Atmosphere:

1 psi = 0.070307 at

Example: 5 pounds per square inch = 0.351535 technical atmospheres

To Torr:

1 psi = 51.714933 Torr

Example: 5 pounds per square inch = 258.574663 torr

To Millimeter of Mercury:

1 psi = 51.714933 mmHg

Example: 5 pounds per square inch = 258.574663 millimeters of mercury

To Inch of Mercury:

1 psi = 2.03602 inHg

Example: 5 pounds per square inch = 10.180102 inches of mercury

To Kilopound per Square Inch:

1 psi = 0.001 ksi

Example: 5 pounds per square inch = 0.005 kilopounds per square inch

To Kilogram-force per Square Centimeter:

1 psi = 0.070307 kgf/cm²

Example: 5 pounds per square inch = 0.351535 kilograms-force per square centimeter

To Kilogram-force per Square Meter:

1 psi = 703.06958 kgf/m²

Example: 5 pounds per square inch = 3515.347898 kilograms-force per square meter

To Millimeter of Water Column:

1 psi = 703.06958 mmH₂O

Example: 5 pounds per square inch = 3515.347898 millimeters of water column

To Inch of Water Column:

1 psi = 27.679905 inH₂O

Example: 5 pounds per square inch = 138.399524 inches of water column

Frequently Asked Questions

Standard car tire pressure: 32-35 PSI (when cold) Always check your specific vehicle:

Driver's door jamb sticker (most reliable)
Owner's manual
Fuel filler door (some vehicles) By vehicle type:
Compact cars: 30-33 PSI
Sedans: 32-35 PSI
SUVs/Light trucks: 35-45 PSI
High-performance: 36-40 PSI Important: Check when tires are COLD (before driving). Tire pressure increases 4-6 PSI after driving. Convert to your region: PSI to Bar →

Convert Pound per Square Inch

Need to convert Pound per Square Inch to other pressure units? Use our conversion tool.

Go to Pressure Converter Convert from Pound per Square Inch

Pound per Square Inch Quick Info

psi

Symbol:psi

Category:Pressure

System:Various

Convert Pound per Square Inch

Popular Conversions

See all pressure conversions →

Pound per Square Inch (psi) - Unit Information & Conversion

🔄 Quick Convert Pound per Square Inch

What is a Pound per Square Inch?

History of the Pound per Square Inch

Quick Answer

Quick Comparison Table

Definition

Real-World Examples

Automotive Tire Pressure

Air Compressors & Pneumatic Tools

Plumbing & Water Systems

HVAC & Refrigeration

Hydraulic Systems

Common Uses

Automotive Industry

Manufacturing & Industry

Construction

HVAC & Refrigeration

Plumbing

Common Conversion Mistakes to Avoid

Pound per Square Inch Conversion Formulas

Frequently Asked Questions

What is a good PSI for car tires?

How do I convert PSI to bar?

What does PSIG vs PSIA mean?

What is 100 PSI in bar and kPa?

Is 40 PSI good tire pressure?

How many PSI in 1 atmosphere?

What PSI should I set my air compressor to?

Why is PSI used instead of bar in the US?

Convert Pound per Square Inch

Pound per Square Inch Quick Info

Related Pressure Units

Popular Conversions