🔧 Pressure Unit Converter
Convert between different pressure units instantly. Supports psi, bar, kPa, atm, MPa, Pa, Torr, and more. Perfect for engineers, scientists, and anyone working with pressure measurements.
What Is Pressure?
Pressure is defined as the force applied perpendicular to a surface per unit area. The SI unit for pressure is the pascal (Pa), which is equivalent to one newton per square meter (N/m²).
In practice, many different pressure units are used in various fields:
- psi — pounds per square inch (common in the US, automotive, and tire pressure)
- bar — metric unit, approximately equal to atmospheric pressure at sea level
- kPa / MPa — kilopascal / megapascal (SI units, common in engineering)
- atm — standard atmosphere (reference atmospheric pressure)
- Torr / mmHg — millimeter of mercury (common in vacuum and medical applications)
- inHg — inch of mercury (weather and aviation)
- mmH₂O — millimeter of water (low-pressure applications)
How the Converter Works
This converter uses the pascal (Pa) as the base unit for all conversions:
Value in Pa = Input Value × Conversion Factor (from unit to Pa)
Result = Value in Pa ÷ Conversion Factor (to unit from Pa)
The conversion factors used are:
- 1 psi = 6,894.757 Pa
- 1 bar = 100,000 Pa
- 1 kPa = 1,000 Pa
- 1 MPa = 1,000,000 Pa
- 1 atm = 101,325 Pa
- 1 Torr = 133.322 Pa
- 1 mbar = 100 Pa
- 1 inHg = 3,386.389 Pa
- 1 mmH₂O = 9.80665 Pa
Why Use This Pressure Unit Converter?
- Comprehensive Units: Supports 10+ common pressure units.
- Instant Results: Get accurate conversions in real-time.
- All Conversions: See the value in every supported unit at once.
- Visual Chart: Compare pressure values across different units.
- Swap Feature: Quickly swap the "from" and "to" units.
- Free & Private: No registration, no data storage.
❓ Pressure Unit Converter FAQ
What is the SI unit for pressure?
The SI unit for pressure is the pascal (Pa), which is equal to one newton per square meter (N/m²).
How do I convert psi to bar?
Multiply psi by 0.0689476 to get bar. For example, 100 psi × 0.0689476 = 6.895 bar.
How do I convert bar to psi?
Multiply bar by 14.5038 to get psi. For example, 1 bar × 14.5038 = 14.504 psi.
What is the difference between psi and bar?
psi (pounds per square inch) is an imperial unit used primarily in the US. Bar is a metric unit where 1 bar ≈ 14.504 psi. Both are commonly used for measuring pressure.
What is standard atmospheric pressure in different units?
1 atm = 101.325 kPa = 14.696 psi = 1.01325 bar = 760 Torr = 29.921 inHg = 10,332 mmH₂O.
What is the difference between Torr and mmHg?
Torr and mmHg (millimeter of mercury) are nearly identical. 1 Torr ≈ 1 mmHg. The exact value is 1 Torr = 1.00000014 mmHg, but for practical purposes they are interchangeable.
How do I convert kPa to psi?
Multiply kPa by 0.145038 to get psi. For example, 100 kPa × 0.145038 = 14.504 psi.
What is MPa used for?
MPa (megapascal) is commonly used in engineering and materials science for measuring high pressures, such as in hydraulic systems, structural engineering, and material strength testing. 1 MPa = 1,000 kPa = 145.038 psi.
How do I convert atm to kPa?
Multiply atm by 101.325 to get kPa. For example, 1 atm × 101.325 = 101.325 kPa.
What is the pressure unit used in weather forecasting?
Weather forecasts typically use millibars (mbar), hectopascals (hPa), or inches of mercury (inHg). 1 mbar = 1 hPa = 100 Pa.
What is the difference between absolute pressure and gauge pressure?
Absolute pressure is measured relative to a perfect vacuum. Gauge pressure is measured relative to atmospheric pressure. This converter handles absolute pressure units (psi, bar, kPa, etc.) for standard conversions.
How do I convert mmH₂O to Pa?
Multiply mmH₂O by 9.80665 to get Pa. For example, 1 mmH₂O × 9.80665 = 9.80665 Pa.
Is this converter accurate for scientific work?
This converter uses standard conversion factors based on SI definitions. For high-precision scientific work, always verify with official standards (NIST, IUPAC, etc.).
Can I use this converter for vacuum pressure?
Yes, this converter supports units commonly used in vacuum applications, including Torr, mbar, Pa, and inHg.
Is this calculator free?
Yes, this calculator is completely free to use. No registration or personal data storage is required. All calculations are performed in your browser.