Pressure Converter

About the Pressure Converter

A pressure converter transforms between pascals (Pa), kilopascals (kPa), megapascals (MPa), bars, atmospheres (atm), pounds per square inch (PSI), millimetres of mercury (mmHg, also called Torr), and inches of mercury (inHg). Pressure measurement appears across diverse fields: tyre inflation uses PSI or bar; weather forecasts use hectopascals (hPa) or millibars; blood pressure uses mmHg; industrial hydraulics uses MPa or bar; vacuum systems use Torr; and atmospheric science uses atm. Each industry settled on different units historically, making conversion essential when working across disciplines. Our converter handles the full pressure range from near-perfect vacuum to tens of thousands of atmospheres used in high-pressure industrial processes.

How It Works

Base unit: Pascal (Pa) = 1 Newton per square metre (N/m²). Key conversions: 1 standard atmosphere (atm) = 101,325 Pa = 1.01325 bar = 14.6959 PSI = 760 mmHg = 29.921 inHg. 1 bar = 100,000 Pa = 0.986923 atm = 14.5038 PSI. 1 PSI = 6,894.76 Pa = 0.0689476 bar = 0.068046 atm = 51.715 mmHg. 1 mmHg = 133.322 Pa. 1 hPa (hectopascal) = 100 Pa = 1 millibar. Standard sea-level atmospheric pressure: 1013.25 hPa = 1013.25 mbar = 29.921 inHg = 14.696 PSI. Tyre pressure example: 32 PSI = 32 × 6,894.76 / 100,000 = 2.206 bar = 2.206 × 1,000 = 2,206 hPa.

Tips & Best Practices

• ✓Tyre pressure: always check when cold (not driven in the last 3 hours). Recommended is typically 30-35 PSI = 2.07-2.41 bar for passenger cars. Check the sticker inside the driver's door, not the maximum pressure on the tyre sidewall.
• ✓Blood pressure: expressed in mmHg. Normal: below 120/80 mmHg. High: above 130/80 mmHg. 120 mmHg = 15.99 kPa = 2.32 PSI — very low by industrial standards but sufficient to drive blood through the body.
• ✓Weather barometric pressure: 1013.25 hPa = standard sea level. Below 1000 hPa often indicates low pressure systems / storms. Above 1020 hPa indicates fair weather high pressure.
• ✓Altitude effect: atmospheric pressure decreases with altitude. At 5,500 m (18,045 ft, altitude of Everest base camp): pressure ≈ 500 hPa = half sea-level pressure. At 10,000 m cruising altitude: ≈ 265 hPa.
• ✓Scuba diving: pressure increases by 1 atm per 10 metres of water depth. At 30 m depth: 4 atm total = 4 × 14.696 = 58.8 PSI absolute. Understanding pressure prevents decompression sickness.
• ✓Vacuum measurement: pressures below atmospheric are often expressed in Torr (= 1 mmHg). A "rough vacuum" is 1-0.001 Torr; high vacuum is below 10^-3 Torr; ultra-high vacuum is below 10^-9 Torr.
• ✓Hydraulic systems: industrial hydraulics operates at 100-350 bar = 1,450-5,076 PSI. High-pressure water cutting uses up to 6,000 bar = 87,000 PSI — enough to cut through steel.
• ✓Pressure cooker: operates at approximately 1.03 bar (15 PSI) above atmospheric = 2.03 bar absolute. This raises the boiling point of water to about 121°C (250°F), cooking food faster.

Who Uses This Calculator

Mechanics and drivers checking tyre pressure in different unit systems. Meteorologists and weather enthusiasts interpreting barometric pressure. Medical professionals measuring and interpreting blood pressure. Engineers designing hydraulic and pneumatic systems. Scuba divers calculating gas consumption and decompression limits. HVAC technicians working with refrigerant pressures. Laboratory scientists working with vacuum systems and pressure vessels.