How To Convert Pounds per Square Inch to Torr
Formula: torr = psi × 51.7149325716
Example: Convert 30 psi to torr.
30 × 51.7149325716 = 1551.447977148 torr
To do it by hand, multiply your psi value by 51.7149325716. This number tells you how many torr are inside 1 psi. If you need to go backward, divide torr by 51.7149325716 to get psi. For quick estimates, you can round 51.7149325716 to about 52, then refine if needed.
Quick Answer
1 psi = 51.7149325716 torr
- 10 psi = 517.149325716 torr
- 30 psi = 1551.447977148 torr
- 50 psi = 2585.74662858 torr
Conversion Formula
torr = psi × 51.7149325716 psi = torr ÷ 51.7149325716
This means psi and torr are just two different ways to measure pressure. The number 51.7149325716 is the fixed ratio between them, based on standard definitions. So every time you multiply psi by this factor, you get the same correct pressure in torr.
- Write your pressure in psi.
- Multiply by 51.7149325716.
- The result is your pressure in torr.
- To convert back, divide torr by 51.7149325716.
Pound per square inch
A pound per square inch is a pressure unit that tells how many pounds of force press on one square inch of area. Its symbol is psi.
It grew popular in the United States with industrial engineering, plumbing, air systems, and mechanical gauges. It is still widely used because many tools and pressure dials are labeled in psi.
- Tire pressure on cars, bikes, and trucks
- Air compressors and pneumatic tools
- Water pressure in plumbing systems
- Hydraulic systems in machines and lifts
- Pressure regulators for gas cylinders
Torr
A torr is a pressure unit mainly used for vacuum and low pressure measurements. Its symbol is torr.
The torr is linked to the standard atmosphere and was named after Evangelista Torricelli, who helped early pressure science with mercury barometers. It is commonly used in laboratories and vacuum technology.
- Vacuum chambers in labs and research
- Vacuum pumps and system specifications
- Thin film coating and sputtering equipment
- Semiconductor and electronics manufacturing vacuum levels
- Leak testing and vacuum system troubleshooting
Is this Conversion of Pounds per Square Inch To Torr Accurate?
Yes. This conversion is based on standard, widely accepted definitions used in science and engineering. We use 1 psi = 6894.757293168 pascals (from the exact inch and the defined pound force relationship) and 1 torr = 101325/760 pascals (tied to the standard atmosphere). Dividing these gives the fixed factor 1 psi = 51.7149325716 torr, which is consistent across textbooks, calibration work, and technical references. For more details on how these standards are chosen and checked, read our accuracy standards.
Real Life Examples
Here are practical places where converting psi to torr helps, especially when a device manual uses psi but lab or vacuum equipment uses torr.
- Vacuum chamber backfill: A chamber is backfilled to 2 psi above a reference point. That is 2 × 51.7149325716 = 103.4298651432 torr, useful when a gauge reads in torr.
- Pressure regulator check: A low pressure regulator output is set to 5 psi for a test line. In torr, that is 258.574662858 torr, helpful if your sensor logs pressure in torr.
- Leak test threshold: A procedure says stop the test if pressure rises by 0.5 psi. That rise equals 25.8574662858 torr, making it easier to compare with a torr-based vacuum gauge.
- Pneumatic control in a lab setup: A lab actuator needs 15 psi to operate. That corresponds to 775.723988574 torr, so you can match settings when using mixed-unit documentation.
- Compressed air line label: A line is marked 60 psi max. In torr, that is 3102.895954296 torr, useful when translating specs into a vacuum system report format.
- Calibration point: A sensor is checked at 10 psi. The equivalent is 517.149325716 torr, which can be entered directly into calibration software that expects torr.
- Higher pressure test: A test fixture is run at 100 psi. That is 5171.49325716 torr, useful for comparison if results are stored in torr.
Quick Tips
- Remember the anchor: 1 psi = 51.7149325716 torr.
- For a fast estimate, use 1 psi ≈ 52 torr, then adjust if you need more accuracy.
- To convert torr to psi quickly, divide by about 52, then refine using 51.7149325716.
- Common mental checks: 10 psi ≈ 517 torr, 50 psi ≈ 2586 torr, 100 psi ≈ 5171 torr.
- Keep consistent rounding in reports, round only at the final step, not during multiplication.