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🔧 Pressure Unit Converter

Pressure Unit Converter

Inputs

Conversion Results

Enter a value to convert

Calculator Description

Pressure is force per unit area, expressed in various units across different industries. This calculator converts between major pressure units including Pa, kPa, bar, atm, psi, mmHg, cmH₂O, and inH₂O.

What this calculator finds

It accurately converts an input pressure value from the selected source unit to the target unit. All conversions are based on the standard atmospheric pressure of 1 atm = 101,325 Pa.

Why it matters

  • Different countries and industries use different pressure units, making accurate conversion essential
  • Unit confusion in fluid piping, pressure vessels, and HVAC design can cause critical errors
  • Calibration of instruments and data comparison require conversion to a common unit basis

Formula

Pressure Unit Conversion Formulas

All pressure units are converted using exact conversion factors based on the standard atmospheric pressure of 1 atm = 101,325 Pa.

1 atm=101,325 Pa=101.325 kPa=1.01325 bar1\ \text{atm} = 101{,}325\ \text{Pa} = 101.325\ \text{kPa} = 1.01325\ \text{bar}
1 atm=14.696 psi=760 mmHg=10,332.6 cmH2O1\ \text{atm} = 14.696\ \text{psi} = 760\ \text{mmHg} = 10{,}332.6\ \text{cmH}_2\text{O}
  • Pa (Pascal) — SI base unit, 1 N/m²
  • atm (표준 대기압) — Standard atmospheric pressure at sea level
  • bar — Exactly equal to 100,000 Pa
  • psi — Commonly used in US/UK, 1 lbf/in²
  • mmHg — Based on mercury column, used in medical fields
  • cmH₂O / inH₂O — Water column based, suitable for low-pressure measurement

General conversion formula

Ptarget=Psource(CtargetCsource)P_{\text{target}} = P_{\text{source}}\left(\dfrac{C_{\text{target}}}{C_{\text{source}}}\right)

where C is the Pa-equivalent conversion factor for each unit.

Useful Tips

Practical tips

  • 1 bar ≈ 1 atm ≈ 14.5 psi, useful for quick approximations
  • Piping design typically uses bar or psi; medical fields use mmHg
  • High vacuum applications typically use Pa or Torr

Limitations & cautions

  • You must distinguish between gauge pressure and absolute pressure when entering values
  • This calculator uses absolute pressure; add atmospheric pressure (101.325 kPa) for gauge pressure
  • Mercury/water column units may vary slightly depending on temperature and gravitational acceleration