Pressure Converter

Convert bar, psi, pascal, atmosphere, kilopascal, and more

💡 Tip: Press Ctrl+D for dark mode, Ctrl+K to focus converter

🌪️ Pressure Converter

Convert between bar, psi, pascal, atmosphere, and more

💡 Quick Tip: 1 bar ≈ 14.5 psi ≈ 100,000 Pa
1 Bar = 14.5038 PSI

Pressure Conversion Guide

Common Pressure Conversions

From To Multiply By Example
Bar PSI 14.5038 1 bar = 14.5038 psi
PSI Bar 0.0689476 1 psi = 0.0689 bar
Bar Pascal 100,000 1 bar = 100,000 Pa
Pascal Bar 0.00001 100,000 Pa = 1 bar
Atmosphere Bar 1.01325 1 atm = 1.01325 bar
Atmosphere PSI 14.696 1 atm = 14.696 psi
kPa PSI 0.145038 100 kPa = 14.5038 psi
Torr mmHg 1 1 torr = 1 mmHg
Atmosphere Torr 760 1 atm = 760 torr

Understanding Pressure Units

SI Units (International System)

Pascal (Pa) - The SI base unit of pressure. Named after Blaise Pascal. Defined as one newton per square meter (N/m²). Small unit - atmospheric pressure is ~101,325 Pa.

Kilopascal (kPa) - 1,000 pascals. More practical for everyday use. Standard atmospheric pressure is 101.325 kPa.

Megapascal (MPa) - 1,000,000 pascals. Used in engineering for high-pressure applications like hydraulics.

Metric Units

Bar - Exactly 100,000 pascals (100 kPa). Commonly used in meteorology and engineering. Close to atmospheric pressure (1 atm = 1.01325 bar).

Millibar (mbar) - 1/1,000 of a bar or 100 pascals. Standard unit in meteorology for atmospheric pressure.

Imperial/US Units

PSI (Pounds per Square Inch) - Pressure from one pound-force applied to one square inch. Standard in the US for tire pressure, compressed air, and industrial applications.

Atmospheric Units

Atmosphere (atm) - Standard atmospheric pressure at sea level. Equals 101,325 Pa, 1.01325 bar, or 14.696 psi. Used in chemistry and diving.

Torr - 1/760 of an atmosphere. Named after Evangelista Torricelli, inventor of the barometer. Used in vacuum measurements.

mmHg (Millimeters of Mercury) - Height of mercury column at 0°C. Practically identical to torr. Used in medicine (blood pressure) and meteorology.

Practical Pressure Examples

  • 🌍 Sea Level Atmospheric Pressure: 1 atm = 1.01325 bar = 14.696 psi = 101.325 kPa
  • 🚗 Car Tire Pressure: 30-35 psi = 2.07-2.41 bar = 207-241 kPa
  • 🚲 Bicycle Tire (Road): 80-130 psi = 5.5-9 bar = 550-900 kPa
  • ⚽ Soccer Ball: 8.5-15.6 psi = 0.6-1.1 bar = 60-110 kPa
  • 🏀 Basketball: 7.5-8.5 psi = 0.52-0.59 bar = 52-59 kPa
  • 🩺 Normal Blood Pressure: 120/80 mmHg (systolic/diastolic)
  • ☕ Espresso Machine: 9 bar = 130.5 psi = 900 kPa
  • 🏔️ Mount Everest Summit: 0.33 atm = 0.34 bar = 4.89 psi
  • ✈️ Airplane Cabin: 0.75-0.85 atm = 11-12.5 psi
  • 🏊 10m Underwater: 2 atm = 2.03 bar = 29.4 psi
  • 🔬 High Vacuum: < 0.001 torr
  • 💎 Diamond Formation: ~50,000 atm = 50,000 bar

Why Different Pressure Units?

Different pressure units evolved for different applications:

  • 🔬 Pascal: SI standard - fundamental for physics and engineering calculations
  • 🌡️ Bar: Convenient magnitude close to atmospheric pressure - popular in Europe
  • 🇺🇸 PSI: Imperial unit - standard in US industry and automotive
  • 🌍 Atmosphere: Based on Earth's average sea-level pressure - diving and chemistry
  • 🩺 mmHg/Torr: Medical tradition (blood pressure) and vacuum science
  • ☁️ Millibar: Meteorology standard for weather forecasting

Pressure Conversion Formulas

Bar to PSI:

psi = bar × 14.5038

PSI to Bar:

bar = psi × 0.0689476

Bar to Pascal:

Pa = bar × 100,000

Pascal to Bar:

bar = Pa ÷ 100,000

Atmosphere to Bar:

bar = atm × 1.01325

Atmosphere to PSI:

psi = atm × 14.696

Quick Mental Math Tips

Bar to PSI (approximate):

  • Multiply bar by 15 (slightly high) → Example: 2 bar × 15 ≈ 30 psi (actual: 29.01 psi) ✓
  • More accurate: multiply by 14.5

PSI to Bar (approximate):

  • Divide psi by 15 → Example: 30 psi ÷ 15 = 2 bar ✓
  • More accurate: divide by 14.5 or multiply by 0.07

Bar to kPa:

  • Multiply bar by 100 → Example: 2 bar × 100 = 200 kPa ✓

Atmosphere to PSI:

  • Remember: 1 atm ≈ 15 psi → Example: 2 atm ≈ 30 psi (actual: 29.39 psi)

Pressure in Different Contexts

Automotive & Tires:

  • 🚗 Car tires: 32 psi = 2.2 bar = 220 kPa (typical)
  • 🚙 SUV tires: 35-40 psi = 2.4-2.8 bar
  • 🏍️ Motorcycle: 28-42 psi (front/rear)
  • 🚚 Truck tires: 80-100 psi = 5.5-7 bar

Diving & Underwater:

  • 🏊 Every 10m depth: +1 atm pressure
  • 🤿 Recreational diving limit: ~40m = 5 atm
  • 🌊 Deepest ocean (Mariana): ~1,100 atm = 16,000 psi

Weather & Altitude:

  • ☁️ Low pressure system: < 1013 mbar (indicates storms)
  • ☀️ High pressure system: > 1013 mbar (clear weather)
  • 🏔️ Pressure drops ~12% per 1,000m altitude
  • ✈️ Cruising altitude (10km): ~0.25 atm

Industrial & Medical:

  • 💉 Syringe injection: 1-10 psi
  • 🩺 Blood pressure cuff: 0-300 mmHg
  • 🔧 Hydraulic systems: 1,500-3,000 psi = 100-200 bar
  • ⚙️ Industrial compressor: 100-150 psi = 7-10 bar

Historical Context

  • 📜 Torricelli (1643): Invented the barometer, discovered atmospheric pressure
  • 🎓 Pascal (1648): Proved atmospheric pressure decreases with altitude
  • 🔬 SI Adoption (1971): Pascal became the official SI pressure unit
  • 🌡️ Bar Origin: From Greek "baros" meaning weight - introduced in 1909

Frequently Asked Questions

How do I convert bar to psi?

Multiply the bar value by 14.5038. For example, 2 bar × 14.5038 = 29.01 psi. This conversion is commonly used for tire pressure between European (bar) and US (psi) standards.

How many psi is 1 bar?

1 bar equals 14.5038 psi. For quick estimates, you can round to 14.5 or even 15 psi per bar.

What is atmospheric pressure?

Standard atmospheric pressure at sea level is 1 atm = 101,325 pascals = 1.01325 bar = 14.696 psi = 760 mmHg. It's the pressure exerted by the weight of the Earth's atmosphere.

What is the difference between bar and pascal?

Both measure pressure, but bar is larger. 1 bar = 100,000 pascals (100 kPa). Pascal is the SI unit (very small), while bar is more convenient for practical applications since it's close to atmospheric pressure.

Why is blood pressure measured in mmHg?

Historical tradition from mercury sphygmomanometers (blood pressure cuffs). The original devices measured pressure by the height of a mercury column. 1 mmHg = 1 torr ≈ 133.322 Pa. Normal blood pressure is 120/80 mmHg.

What tire pressure should I use: bar or psi?

Both are correct - just different units. Most European cars spec pressure in bar (e.g., 2.2 bar), while US cars use psi (e.g., 32 psi). Your tire's sidewall shows the max pressure in both units. Use whichever your gauge displays.

How accurate is this pressure converter?

Our converter uses exact conversion factors from international standards (NIST, BIPM). Results are accurate up to 10 decimal places, exceeding the precision of most pressure gauges.

Quick Reference Chart

1 Bar equals:

  • 100,000 pascals (Pa)
  • 100 kilopascals (kPa)
  • 0.1 megapascals (MPa)
  • 14.5038 psi
  • 0.986923 atmospheres (atm)
  • 750.062 torr
  • 750.062 mmHg

1 PSI equals:

  • 6,894.76 pascals (Pa)
  • 6.89476 kilopascals (kPa)
  • 0.0689476 bar
  • 0.068046 atmospheres (atm)
  • 51.7149 torr
  • 51.7149 mmHg

1 Atmosphere equals:

  • 101,325 pascals (Pa)
  • 101.325 kilopascals (kPa)
  • 1.01325 bar
  • 14.696 psi
  • 760 torr
  • 760 mmHg

Common Tire Pressures:

  • 30 psi = 2.07 bar = 207 kPa
  • 32 psi = 2.21 bar = 221 kPa (typical car)
  • 35 psi = 2.41 bar = 241 kPa
  • 40 psi = 2.76 bar = 276 kPa (SUV/truck)