Torr to PSI Converter
Convert from Torr (mmHg) to Pounds per Square Inch (PSI)
Understanding Torr and PSI
The torr is a unit of pressure named after Evangelista Torricelli, who invented the mercury barometer.
- 1 torr is defined as 1/760 of standard atmospheric pressure
- Approximately equal to 1 mmHg (millimeter of mercury)
- Standard atmospheric pressure is 760 torr
- Commonly used in vacuum technology, scientific research, and some medical applications
PSI is a unit of pressure in the imperial and US customary measurement systems.
- Defined as one pound-force applied to one square inch of area
- Standard atmospheric pressure is approximately 14.7 PSI
- Commonly used for tire pressure, hydraulic systems, and industrial applications
- Widely used in the United States and countries using imperial units
Conversion Formula
Torr to PSI:
PSI = Torr × 0.0193368
To convert from torr to PSI, multiply the torr value by approximately 0.0193368.
PSI to Torr:
Torr = PSI × 51.7149
To convert from PSI to torr, multiply the PSI value by approximately 51.7149.
Torr to PSI Conversion Table
| Torr (mmHg) | Pounds per Square Inch (PSI) |
|---|---|
| 50 | 0.9668 |
| 100 | 1.9337 |
| 150 | 2.9005 |
| 200 | 3.8673 |
| 250 | 4.8342 |
| 300 | 5.8010 |
| 350 | 6.7678 |
| 400 | 7.7347 |
| 450 | 8.7015 |
| 500 | 9.6684 |
Historical Context and Applications
Historical Development
The torr unit is named after Evangelista Torricelli, an Italian physicist and mathematician who invented the mercury barometer in 1643. His experiments demonstrated the existence of atmospheric pressure and created a vacuum. The torr has historically been used interchangeably with the millimeter of mercury (mmHg). The PSI unit developed during the Industrial Revolution in England and became standardized with engineering advancements. These units represent two different scientific traditions, with torr being more common in scientific and laboratory settings.
Common Applications
- Torr: Primarily used in vacuum science and technology, where pressures are typically much lower than atmospheric pressure. Also used in medical applications, particularly for measuring blood pressure (though mmHg is the more common term), and in laboratory settings for vacuum distillation and other processes requiring low pressure.
- PSI: Widely used in the United States for practical engineering applications such as tire pressure, hydraulic systems, plumbing, and industrial processes. The standard unit for pressure gauges in American engineering and most consumer applications in the US.
Practical Examples
- Standard atmospheric pressure: 760 torr (14.7 PSI)
- Human blood pressure (normal systolic): ~120 torr (~2.32 PSI)
- Typical laboratory vacuum: 1-10 torr (0.019-0.193 PSI)
- High vacuum: 10⁻³-10⁻⁶ torr (1.93×10⁻⁵-1.93×10⁻⁸ PSI)
- Weather systems: 740-780 torr (14.3-15.1 PSI)
- Enter your value in the torr field
- The converter instantly displays the equivalent in PSI
- Use the swap button to convert from PSI to torr instead
- Results are displayed with 6 decimal places for precision
- For quick reference without calculations, refer to the conversion table above
This converter is particularly useful for scientists and engineers who need to translate between laboratory vacuum measurements and industrial pressure specifications, or for medical professionals working across different measurement systems.