< class="breadcumb-title text-anim" data-cue="slideInUp" data-delay="300">Pressure Converter
Professional Pressure Converter — 35+ Units (Pa, PSI, Bar, atm, mmHg, Torr) | ASLI FORM

Pressure Converter

Convert pressure values between 35+ units with NIST-standard conversion factors and scientific precision up to 10 significant digits.

Quick Reference Values
Conversion Formula
Enter a value to see the conversion formula

Equivalents of 1 Pascal

Live reference table
UnitSymbolEquivalent Value

Pressure Unit Categories

Pressure units are grouped by measurement system, convention, and application. Click any unit group to jump to its detailed information, or click individual units to convert instantly.

Real-World Applications

Different pressure units are standard in different industries and applications. Understanding which unit to use in which context is essential for accurate engineering and scientific work.

Medical & Healthcare

Blood pressure is universally measured in mmHg. Respiratory devices (CPAP, ventilators) commonly use cmH₂O.

mmHg cmH₂O kPa

Automotive

Tire pressure is measured in PSI (US/UK), Bar (Europe), or kPa (SI standard). Engine oil pressure uses PSI or Bar.

PSI Bar kPa

Meteorology

Atmospheric pressure in weather reports uses hectopascal (hPa, equal to millibar) or inches of mercury.

hPa mbar inHg

Hydraulic Systems

Industrial hydraulics operate at high pressures typically measured in Bar, MPa, or PSI (1000–5000 PSI).

Bar MPa PSI

HVAC & Pneumatics

Air duct pressure, gas lines, and pneumatic tools use inH₂O, inHg, or PSI. Low-pressure systems use mmH₂O.

inH₂O inHg PSI

Scuba Diving

Tank pressure is measured in Bar (metric) or PSI (imperial). Depth-pressure uses atm (1 atm per 10m seawater).

Bar PSI atm

Aerospace

Aircraft altimeters use inHg or hPa. Cabin pressure and fuel systems use PSI. Rocket engines use MPa.

inHg hPa MPa

Scientific Research

SI standard uses Pascal. Vacuum science uses Torr or mbar. Material strength testing uses MPa or GPa.

Pa Torr MPa

Oil & Gas

Wellhead and pipeline pressure typically measured in PSI or Bar. KSI used for extreme well pressures.

PSI KSI Bar

Beverage Industry

Carbonation in beer and soda measured in PSI or Bar. Keg systems typically operate at 10–14 PSI.

PSI Bar kPa

Civil Engineering

Concrete compressive strength measured in MPa (SI) or PSI (US). Soil pressure uses kPa or psf.

MPa PSI kPa

Cooking & Kitchen

Pressure cookers operate at ~15 PSI (~1 Bar above atmosphere). Espresso machines use 9 Bar.

PSI Bar kPa

How to Use This Pressure Converter

Our pressure converter is designed for precision, speed, and ease of use. Follow these steps to get accurate conversions instantly.

  • Select Source Unit Choose the pressure unit you want to convert from using the "From" dropdown.
  • Select Target Unit Choose the pressure unit you want to convert to using the "To" dropdown.
  • Enter Your Value Type the pressure value — the result updates instantly as you type.
  • Use Quick Presets Click preset buttons for common values like standard atmosphere (101,325 Pa).
  • Swap Units Click the swap button to reverse the conversion direction instantly.
  • View Formula See the exact conversion factor and formula used for full transparency.

Common Pressure Conversion Formulas

Quick reference for the most frequently used pressure conversions. All factors are based on NIST and BIPM standards.

PSI to Bar
Bar = PSI × 0.0689476
1 PSI = 0.0689476 Bar (exact: 6894.757 / 100000)
Bar to PSI
PSI = Bar × 14.5038
1 Bar = 14.5038 PSI (exact: 100000 / 6894.757)
atm to Pa
Pa = atm × 101,325
Standard atmosphere = exactly 101,325 Pa
mmHg to Pa
Pa = mmHg × 133.322
Conventional mmHg (4°C mercury, standard gravity)
Torr to Pa
Pa = Torr × 133.322
1 Torr = 101325/760 = 133.322368421 Pa (exact)
inH₂O to Pa
Pa = inH₂O × 249.089
Conventional inH₂O at 4°C (39.2°F)
kgf/cm² to Bar
Bar = kgf/cm² × 0.980665
Technical atmosphere ≈ 0.981 Bar
MPa to PSI
PSI = MPa × 145.038
Common in material strength testing
mbar to hPa
hPa = mbar × 1
Millibar and hectopascal are numerically equal

Why Professionals Choose ASLI FORM

Built with precision engineering and premium design, our pressure converter meets the demanding requirements of engineers, scientists, and medical professionals.

  • NIST-Standard Precision All conversion factors verified against NIST and BIPM standards with 10-digit accuracy.
  • Real-Time Results Instant conversion as you type — no submit button, no waiting, no page reloads.
  • Offline Capability Works without internet after page loads. Ideal for field work and remote locations.
  • Universal Device Support Works perfectly from keypad phones to 4K displays with optimized layouts for each.
  • Zero Privacy Invasion No cookies, no analytics, no data collection. Your calculations stay in your browser.
  • Free Forever No subscriptions, no limits, no ads, no hidden fees. Completely free for everyone.

Frequently Asked Questions

Pressure is the force applied perpendicular to the surface of an object per unit area. Mathematically, P = F/A where P is pressure, F is force, and A is area. The SI unit is the Pascal (Pa), which equals one Newton per square meter (N/m²).

Pressure is measured using various instruments:
  • Manometers — U-tube devices using liquid columns (mercury or water)
  • Barometers — For measuring atmospheric pressure
  • Bourdon gauges — Mechanical gauges for industrial applications
  • Digital pressure sensors — Electronic transducers with high precision
  • Piezoelectric sensors — For dynamic pressure measurements
Standard atmospheric pressure (1 atm) is defined as exactly 101,325 Pascal. Here's how it converts to other units:
  • 101,325 Pa (Pascal)
  • 101.325 kPa (kilopascal)
  • 1.01325 bar
  • 1,013.25 mbar (millibar, = hPa)
  • 14.6959 PSI (pounds per square inch)
  • 760 mmHg (millimeters of mercury)
  • 760 Torr
  • 29.9213 inHg (inches of mercury)
  • 10,332.3 mmH₂O (millimeters of water)
  • 406.78 inH₂O (inches of water)
  • 1.03323 kgf/cm² (technical atmosphere)
This value represents the average atmospheric pressure at sea level at 15°C.
Historically, mmHg and Torr were identical. Today they differ by a tiny but measurable amount:
  • 1 Torr = exactly 101325/760 Pa = 133.322368421 Pa (by definition)
  • 1 conventional mmHg = pressure from 1mm mercury at standard gravity = 133.322387415 Pa
The difference is about 0.000014% — negligible for medical and most industrial applications, but significant in scientific metrology. The Torr was redefined in 1954 when the atmosphere was redefined as exactly 101,325 Pa. For practical purposes, they are interchangeable, but our converter uses the exact values for each.
Our converter delivers results accurate to 10 significant digits using conversion factors from official metrology institutes:
  • NIST (National Institute of Standards and Technology, USA)
  • BIPM (Bureau International des Poids et Mesures)
  • IUPAC (International Union of Pure and Applied Chemistry)
All factors are based on internationally agreed definitions. This level of precision is suitable for engineering calculations, scientific research, HVAC design, hydraulic systems, and most industrial applications. For legal metrology or custody transfer applications, always verify against certified reference standards.
Water column units measure pressure as the height of a water column that would produce that pressure. They're commonly used in:
  • HVAC systems — duct pressure (typically 0.1-2 inH₂O)
  • Medical devices — CPAP machines use cmH₂O
  • Gas distribution — low-pressure gas lines
  • Industrial process control — tank level measurement
Values are typically referenced to water at 4°C (39.2°F) where water's density is maximum (999.972 kg/m³). Conventional values use standard gravity (9.80665 m/s²). Key conversions:
  • 1 mmH₂O = 9.80665 Pa
  • 1 cmH₂O = 98.0665 Pa
  • 1 inH₂O = 249.089 Pa
  • 1 ftH₂O = 2,989.07 Pa
This is a critical distinction in pressure measurement:
  • Absolute pressure (psia, bara) is measured relative to a perfect vacuum (zero pressure). Standard atmospheric pressure is 14.7 psia or 1.013 bara.
  • Gauge pressure (psig, barg) is measured relative to ambient atmospheric pressure. A tire at 32 psig is actually at 46.7 psia (32 + 14.7).
Conversion: Absolute = Gauge + Atmospheric

Our converter handles pure numerical conversion between units — it doesn't automatically convert between gauge and absolute. The user must specify whether values are gauge or absolute based on context. Most pressure gauges read gauge pressure unless specified otherwise (like barometers).
Blood pressure is measured in millimeters of mercury (mmHg) due to historical reasons dating back to the first mercury sphygmomanometer invented by Scipione Riva-Rocci in 1896. Mercury was used because:
  • High density — A mercury column is 13.6× shorter than a water column for the same pressure, making devices practical
  • Stable properties — Mercury doesn't evaporate or stick to glass
  • Linear response — Direct visual reading without calibration
Normal blood pressure is approximately 120/80 mmHg (systolic/diastolic). Although modern digital blood pressure monitors use electronic sensors, they still report in mmHg for consistency with medical literature and clinical standards. 1 mmHg ≈ 133.322 Pa or 0.133 kPa.
Common tire pressure conversions:
  • PSI to Bar: Multiply by 0.0689476 (or divide by 14.5038)
  • Bar to PSI: Multiply by 14.5038
  • PSI to kPa: Multiply by 6.89476
Common tire pressures:
  • Passenger car: 30-35 PSI = 2.1-2.4 Bar = 210-240 kPa
  • SUV/truck: 35-40 PSI = 2.4-2.8 Bar = 240-280 kPa
  • Bicycle road: 80-130 PSI = 5.5-9 Bar = 550-900 kPa
  • Bicycle mountain: 30-50 PSI = 2-3.5 Bar = 200-350 kPa
Always check your vehicle's door jamb sticker or owner's manual for manufacturer-recommended tire pressure.
KSI (kilopound per square inch) equals 1,000 PSI and is used for extremely high pressures, primarily in:
  • Material strength — Steel yield strength (e.g., A36 steel = 36 KSI = 36,000 PSI)
  • Oil & gas wells — High-pressure reservoirs (10-30 KSI common)
  • Aerospace — Rocket engine chambers and high-performance materials
  • Deep-sea engineering — Subsea equipment ratings
Conversions:
  • 1 KSI = 1,000 PSI
  • 1 KSI = 6.89476 MPa
  • 1 KSI = 68.9476 Bar
  • 1 KSI = 68.046 atm
For reference, the deepest point in the ocean (Mariana Trench) is about 15.75 KSI (1,086 Bar).
Both are SI-derived pressure units, but differ in scale:
  • 1 Pascal (Pa) = 1 Newton per square meter (1 N/m²) — very small unit
  • 1 Bar = 100,000 Pascal (10⁵ Pa) — convenient for everyday use
Why both exist: The Pascal is the official SI unit but is impractically small for most applications (atmospheric pressure would be 101,325 Pa). The Bar was adopted as a practical unit close to atmospheric pressure (1 atm ≈ 1.013 bar). Common multiples:
  • 1 kPa = 1,000 Pa
  • 1 MPa = 1,000,000 Pa = 10 Bar
  • 1 GPa = 1,000,000,000 Pa (used for material strength)
  • 1 mbar = 0.001 Bar = 100 Pa = 1 hPa
Yes, but with an important caveat about vacuum notation:
  • Rough vacuum (1 to 1000 mbar): Use mbar, Torr, or Pa directly
  • Medium vacuum (10⁻³ to 1 mbar): Use Pa or Torr
  • High vacuum (10⁻⁷ to 10⁻³ mbar): Use Pa (often in scientific notation)
  • Ultra-high vacuum (<10⁻⁷ mbar): Use Pa with scientific notation
Our converter handles scientific notation automatically (e.g., 1e-6 = 0.000001). Common vacuum units include Torr, mbar/micron, and Pa. Note that some vacuum measurements are expressed as "inches of mercury vacuum" (inHg vac) — a gauge reading where atmospheric pressure = 0 and perfect vacuum = 29.92 inHg vac.
Yes, this converter is suitable for most engineering applications including:
  • Mechanical engineering — Hydraulic and pneumatic system design
  • Civil engineering — Concrete strength, soil pressure, water systems
  • Chemical engineering — Process pressure, reactor design
  • HVAC engineering — Duct pressure, refrigerant systems
  • Aerospace engineering — Cabin pressure, fuel systems
  • Material science — Compressive and tensile strength
Limitations: For legal metrology, custody transfer, or safety-critical applications, always verify conversions against certified reference standards and official documentation from NIST or your national metrology institute. Engineering judgment should always consider uncertainties, safety factors, and application-specific standards (ASME, API, ISO).
Yes. All conversions happen locally in your browser using JavaScript. Once the page loads, there is no server communication, no API calls, and no internet dependency for conversions. This makes it ideal for:
  • Field work in remote locations
  • Laboratory environments with restricted internet
  • Aircraft (offline use during flights)
  • Marine applications
  • Secure facilities with no external connectivity
The only internet requirement is the initial page load. After that, the tool works completely offline.
A technical atmosphere (at) is an obsolete unit equal to exactly 1 kilogram-force per square centimeter (1 kgf/cm²). It's defined as:
  • 1 at = 98,066.5 Pa (exact)
  • 1 at = 0.980665 Bar
  • 1 at = 0.967841 atm (standard atmosphere)
  • 1 at = 14.2233 PSI
The technical atmosphere was widely used in engineering before SI adoption and still appears in older European and Russian technical documentation. It differs from the standard atmosphere (atm) by about 3.3%. The "at" represents pressure from 10m of water, while "atm" is atmospheric pressure at sea level.
We take accuracy seriously. If you believe a conversion factor is incorrect or want to suggest adding a new pressure unit, please contact our team:
  • Phone: +91-7011993433 (Mon-Sat, 9 AM to 7 PM IST)
  • WhatsApp: Same number with pre-filled message
  • Email: support@asliform.in
When reporting a conversion issue, please include:
  • The source unit and value
  • The target unit
  • The result our converter gave
  • The expected correct result
  • A reference source (NIST, textbook, etc.)
Our team verifies all conversion factors against primary metrology sources and updates the converter promptly when legitimate discrepancies are found.

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