# Pressure Converter

Free pressure converter. Convert between Pascal, bar, atmosphere, PSI, torr, and mmHg instantly with exact conversion factors.

## What this calculates

Convert between all common pressure units including Pascal, kilopascal, bar, atmosphere, PSI, torr, and mmHg. Uses internationally standardized conversion factors for precise results.

## Inputs

- **Value** — min 0
- **From** — options: Pascal (Pa), Hectopascal (hPa), Kilopascal (kPa), Megapascal (MPa), Bar (bar), Atmosphere (atm), PSI (psi), Torr (torr), mmHg
- **To** — options: Pascal (Pa), Hectopascal (hPa), Kilopascal (kPa), Megapascal (MPa), Bar (bar), Atmosphere (atm), PSI (psi), Torr (torr), mmHg

## Outputs

- **Result** — The converted pressure value.
- **Conversion** — formatted as text — Step-by-step conversion explanation.

## Details

Pressure conversion is essential in engineering, meteorology, medicine, and automotive applications. Different fields use different pressure units, making conversion a frequent necessity.

Key Conversion Factors

- 1 atmosphere (atm) = 101,325 Pa (exact, by definition)

- 1 bar = 100,000 Pa (exact)

- 1 PSI = 6,894.757 Pa

- 1 torr = 1/760 atm (exact definition)

- 1 mmHg ≈ 1 torr (very close but technically different)

- 1 atm = 14.696 PSI

- 1 bar = 14.504 PSI

Common Applications

- Tire pressure: measured in PSI (US) or bar (Europe)

- Weather: hectopascals (hPa) or millibars

- Blood pressure: mmHg

- Scuba diving: atm or bar

- Industrial: kPa or MPa

## Frequently Asked Questions

**Q: How do I convert PSI to bar?**

A: Divide the PSI value by 14.5038. For example, 30 PSI = 30 / 14.5038 = 2.0684 bar. Alternatively, multiply PSI by 0.0689476. Tire pressure of 32 PSI equals approximately 2.21 bar.

**Q: What is the difference between torr and mmHg?**

A: Torr and mmHg are nearly identical but technically different. 1 torr is exactly 1/760 of an atmosphere (101325/760 Pa = 133.3224 Pa). 1 mmHg is defined as 133.3224 Pa at 0°C under standard gravity. The difference is negligible for most practical purposes.

**Q: Why is blood pressure measured in mmHg?**

A: Blood pressure is measured in millimeters of mercury (mmHg) because early sphygmomanometers used mercury columns. A reading of 120/80 mmHg means the systolic pressure pushes mercury 120mm high and diastolic 80mm. Though modern devices are digital, the mmHg unit persists.

**Q: How many PSI is 1 atmosphere?**

A: One standard atmosphere equals 14.696 PSI (pounds per square inch). This is the average atmospheric pressure at sea level. So when a tire gauge reads 32 PSI, the absolute pressure inside the tire is 32 + 14.696 = 46.696 PSI absolute.

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Source: https://vastcalc.com/calculators/conversion/pressure-converter
Category: Conversion
Last updated: 2026-04-21