To convert millitorr to pounds per square foot, multiply by 0.002784495557. That factor is the whole relationship: both units measure pressure, so the conversion is a proportion with no offset and no substance-specific constant.
One thousandth of a torr, the working unit of vacuum deposition. The unit US building codes give floor, roof and wind loads in.
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 foot, so you can sanity-check whether your answer is a plausible size.
The formula
millitorr- The amount you are converting, in millitorr
0.00278449555747- The exact number of pounds per square foot in one millitorr
pounds per square foot- The converted result
How it works, step by step
- Enter the value in millitorr.
- It is multiplied by 0.00278449555747, the exact factor between the two units.
- The answer is shown in pounds per square foot, with the reverse conversion beneath it.
- Check the reference table if you want a figure of comparable size.
Worked examples
Sea-level air: 7.6e+05 mTorr in pounds per square foot
Take sea-level air, roughly 7.6e+05 mTorr. The conversion is a single multiplication — 7.6e+05 × 0.0027845 — giving 2116.22 psf. Because the relationship is proportional, doubling the input doubles the answer to 4232.43 psf.
A domestic water main: 3e+06 mTorr in pounds per square foot
Take a domestic water main, roughly 3e+06 mTorr. The conversion is a single multiplication — 3e+06 × 0.0027845 — giving 8353.49 psf. Because the relationship is proportional, doubling the input doubles the answer to 16,707 psf.
How to read your score
Frequently asked questions
How many pounds per square foot are in one millitorr?
Exactly 0.00278449555747. 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 foot?
pounds per square foot = millitorr × 0.00278449555747. Reversed, millitorr = pounds per square foot ÷ 0.00278449555747, which is the same as multiplying by 359.131476191.
Which is the bigger unit, the millitorr or the pound per square foot?
The pound per square foot. One millitorr is only 0.0027845 of a pound per square foot, so it takes 359.131 millitorr to make one pound per square foot.
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 foot?
The unit US building codes give floor, roof and wind loads in.
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 psf in my head?
Plenty of people do this in their head: divide by 360 instead of using the exact factor 0.002784495557. At 100 that shortcut gives 0.27777778 pounds per square foot, off by 0.0006718 pounds per square foot or about 0.24%. Fine for a rough estimate, not fine for anything you are cutting to size or dosing.
Millitorr to pounds per square foot reference tables
| Millitorr | Pounds Per Square Foot |
|---|---|
| 0.5 mTorr | 0.00139225 psf |
| 1 mTorr | 0.0027845 psf |
| 2 mTorr | 0.00556899 psf |
| 3 mTorr | 0.00835349 psf |
| 5 mTorr | 0.0139225 psf |
| 10 mTorr | 0.027845 psf |
| 20 mTorr | 0.0556899 psf |
| 25 mTorr | 0.0696124 psf |
| 50 mTorr | 0.139225 psf |
| 75 mTorr | 0.208837 psf |
| 100 mTorr | 0.27845 psf |
| 250 mTorr | 0.696124 psf |
| 500 mTorr | 1.39225 psf |
| 1000 mTorr | 2.7845 psf |
| 5000 mTorr | 13.9225 psf |
Exact factor: 1 millitorr = 0.00278449555747 pounds per square foot.
| Quantity | mTorr | psf |
|---|---|---|
| Sea-level air | 7.6e+05 mTorr | 2116 psf |
| A car tyre | 1.655e+06 mTorr | 4608 psf |
| Blood pressure, systolic | 1.2e+05 mTorr | 334.1 psf |
| A bicycle tyre | 4.654e+06 mTorr | 1.296e+04 psf |
| A domestic water main | 3e+06 mTorr | 8354 psf |
| A steam boiler | 7.501e+06 mTorr | 2.089e+04 psf |
Published reference values, converted with the same factor this page uses.