In 1 pounds per square inch there are 51.71493 torrs. Meanwhile in 1 torrs there are 0.019337 pounds per square inch. Keep reading to learn more about each unit of measure and how they are calculated. Or just use the Torrs to Pounds per square inch calculator above to convert any number.
* Values rounded to 6 decimal places for readability
To convert PSI (pounds per square inch) to torr, use a fixed pressure conversion factor.
This works because 1 psi = 6,894.757 Pa and 1 torr = 133.322368 Pa, so 1 psi = 51.7149 torr.
Example:
Tip: Torr is common in vacuum pressure work; 760 torr equals 1 atmosphere (atm), and lower torr values mean lower pressure (stronger vacuum).
PSI (pounds per square inch) is a pressure unit used in the US. Torr is a pressure unit based on the millimeter of mercury (mmHg). A PSI to torr conversion changes a pressure value from PSI into torr.
To convert PSI to torr, multiply the PSI value by 51.71493257.
Formula:
torr = PSI × 51.71493257
1 PSI = 51.7149 torr (rounded).
To convert torr to PSI, divide the torr value by 51.71493257.
Formula:
PSI = torr ÷ 51.71493257
A torr is a smaller unit than PSI. Since it takes many small units to equal one larger unit, one PSI turns into about 51.7 torr.
In most real-world use, 1 torr is treated as equal to 1 mmHg. The names differ, but the values match closely enough for common pressure work.
14.7 PSI ≈ 760 torr.
This is a common reference point because 14.7 PSI is close to standard air pressure at sea level.
30 PSI ≈ 1551.45 torr.
Calculation: 30 × 51.71493257 = 1551.4479771 torr.
Use the same conversion factor. Multiply PSI by 51.71493257 to get torr.
If you use PSI gauge (PSIG), remember PSIG is relative to air pressure. Vacuum readings often need PSI absolute (PSIA) to compare with torr in a clean way.
Torr is an absolute pressure unit in most vacuum work. If you start with PSIG, you may need to convert to PSIA first.
Standard atmosphere is close to:
Values can shift a bit with rounding and local air pressure.
The unit conversion itself does not change with temperature. PSI and torr are both pressure units, and the math stays the same.
Temperature can change the pressure of a gas in a system, so your measured PSI or torr value may change as temperature changes.
It depends on your need:
Rounding too early can add error, so keep extra digits until the final step.
The conversion is based on defined relationships between units. In daily use, it’s treated as exact for practical work. Small differences can show up only in high-precision cases due to how mercury-based units are defined and rounded.
The Calculate Box tool to convert pounds per square inch to torrs uses the open source script Convert.js to convert units of measurement. To use this tool, simply type a pounds per square inch value in the box and have it instantly converted to torrs.