This page converts millitorr into pounds per square inch using the factor 1.93367747e-05, and shows the reverse figure alongside it. Both units measure pressure, which is why one number does the whole job.
One thousandth of a torr, the working unit of vacuum deposition. The dominant US pressure unit for tyres, plumbing and compressors.
Gauge versus absolute. A tyre gauge reading 32 psi means 32 psi above atmospheric, which is about 46.7 psi absolute. Converting the number is straightforward; remembering which zero it was measured from is where the mistakes happen. N/mm² and MPa are the same size, so a drawing quoting either is quoting the same stress. The tables underneath give both a plain step-by-step lookup and a list of real quantities expressed in pounds per square inch, so you can sanity-check whether your answer is a plausible size.
The formula
millitorr- The amount you are converting, in millitorr
1.93367747046e-05- The exact number of pounds per square inch in one millitorr
pounds per square inch- The converted result
How it works, step by step
- Enter the value in millitorr.
- It is multiplied by 1.93367747046e-05, the exact factor between the two units.
- The answer is shown in pounds per square inch, with the reverse conversion beneath it.
- Check the reference table if you want a figure of comparable size.
Worked examples
A domestic water main: 3e+06 mTorr in pounds per square inch
A domestic water main comes to about 3e+06 mTorr. Multiplying by the factor: 3e+06 × 1.93368e-05 = 58.0103 psi. Dividing the answer back by 1.93368e-05 returns the figure you started with, which is the quickest way to check you have the factor the right way up.
A steam boiler: 7.5e+06 mTorr in pounds per square inch
Take a steam boiler, roughly 7.5e+06 mTorr. The conversion is a single multiplication — 7.5e+06 × 1.93368e-05 — giving 145.026 psi. Because the relationship is proportional, doubling the input doubles the answer to 290.052 psi.
How to read your score
Frequently asked questions
How many pounds per square inch are in one millitorr?
Exactly 1.93367747046e-05. Every figure on this page is that one number multiplied by your input, so the only rounding is at the display step.
What is the formula to convert millitorr to pounds per square inch?
pounds per square inch = millitorr × 1.93367747046e-05. Reversed, millitorr = pounds per square inch ÷ 1.93367747046e-05, which is the same as multiplying by 51,714.9325715.
Which is the bigger unit, the millitorr or the pound per square inch?
The pound per square inch. One millitorr is only 1.93368e-05 of a pound per square inch, so it takes 51,714.9 millitorr to make one pound per square inch.
What does this quantity actually measure?
Both units measure pressure. That is why a single factor is enough: there is no temperature offset and no material property involved, unlike conversions that cross between different quantities.
What is a millitorr?
One thousandth of a torr, the working unit of vacuum deposition.
What is a pound per square inch?
The dominant US pressure unit for tyres, plumbing and compressors.
Why does my answer differ from another converter?
Almost always because the other tool rounded the factor before multiplying. This page keeps full double precision through the calculation and rounds only for display, and it prints the factor it used so you can see where any difference came from.
Is there a quick way to do mTorr to psi in my head?
Plenty of people do this in their head: divide by 50,000 instead of using the exact factor 0.000019. At 100 that shortcut gives 0.002 pounds per square inch, off by 0.000066 pounds per square inch or about 3.43%. Fine for a rough estimate, not fine for anything you are cutting to size or dosing.
Millitorr to pounds per square inch reference tables
| Millitorr | Pounds Per Square Inch |
|---|---|
| 0.5 mTorr | 9.66839e-06 psi |
| 1 mTorr | 1.93368e-05 psi |
| 2 mTorr | 3.86735e-05 psi |
| 3 mTorr | 5.80103e-05 psi |
| 5 mTorr | 9.66839e-05 psi |
| 10 mTorr | 0.000193368 psi |
| 20 mTorr | 0.000386735 psi |
| 25 mTorr | 0.000483419 psi |
| 50 mTorr | 0.000966839 psi |
| 75 mTorr | 0.00145026 psi |
| 100 mTorr | 0.00193368 psi |
| 250 mTorr | 0.00483419 psi |
| 500 mTorr | 0.00966839 psi |
| 1000 mTorr | 0.0193368 psi |
| 5000 mTorr | 0.0966839 psi |
Exact factor: 1 millitorr = 1.93367747046e-05 pounds per square inch.
| Quantity | mTorr | psi |
|---|---|---|
| Sea-level air | 7.6e+05 mTorr | 14.7 psi |
| A car tyre | 1.655e+06 mTorr | 32 psi |
| Blood pressure, systolic | 1.2e+05 mTorr | 2.32 psi |
| A bicycle tyre | 4.654e+06 mTorr | 90 psi |
| A domestic water main | 3e+06 mTorr | 58.02 psi |
| A steam boiler | 7.501e+06 mTorr | 145 psi |
Published reference values, converted with the same factor this page uses.