This page converts inches of mercury into pounds per square foot using the factor 70.72620475, and shows the reverse figure alongside it. Both units measure pressure, which is why one number does the whole job.
The unit US building codes give floor, roof and wind loads in. US aviation and weather altimeter setting unit.
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. Two tables follow: rounded steps for quick lookup, and a set of real reference quantities converted into pounds per square foot, which is usually more useful than the bare number.
The formula
inches of mercury- The amount you are converting, in inches of mercury
70.7262047474- The exact number of pounds per square foot in one inch of mercury
pounds per square foot- The converted result
How it works, step by step
- Enter the value in inches of mercury.
- It is multiplied by 70.7262047474, 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
A domestic water main: 118 inHg in pounds per square foot
A domestic water main comes to about 118 inHg. Multiplying by the factor: 118 × 70.7262 = 8345.69 psf. Dividing the answer back by 70.7262 returns the figure you started with, which is the quickest way to check you have the factor the right way up.
A bicycle tyre: 183 inHg in pounds per square foot
A bicycle tyre comes to about 183 inHg. Multiplying by the factor: 183 × 70.7262 = 12,942.9 psf. Dividing the answer back by 70.7262 returns the figure you started with, which is the quickest way to check you have the factor the right way up.
How to read your score
Frequently asked questions
How many pounds per square foot are in one inch of mercury?
Exactly 70.7262047474. 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 inches of mercury to pounds per square foot?
pounds per square foot = inches of mercury × 70.7262047474. Reversed, inches of mercury = pounds per square foot ÷ 70.7262047474, which is the same as multiplying by 0.0141390309797.
Which is the bigger unit, the inch of mercury or the pound per square foot?
The inch of mercury. One inch of mercury equals 70.7262 pounds 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 inch of mercury?
US aviation and weather altimeter setting unit.
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 inHg to psf in my head?
Plenty of people do this in their head: multiply by 70 instead of using the exact factor 70.72620475. At 100 that shortcut gives 7000 pounds per square foot, off by 72.62 pounds per square foot or about 1.03%. Fine for a rough estimate, not fine for anything you are cutting to size or dosing.
Inches Of Mercury to pounds per square foot reference tables
| Inches Of Mercury | Pounds Per Square Foot |
|---|---|
| 0.5 inHg | 35.3631 psf |
| 1 inHg | 70.7262 psf |
| 2 inHg | 141.452 psf |
| 3 inHg | 212.179 psf |
| 5 inHg | 353.631 psf |
| 10 inHg | 707.262 psf |
| 20 inHg | 1414.52 psf |
| 25 inHg | 1768.16 psf |
| 50 inHg | 3536.31 psf |
| 75 inHg | 5304.47 psf |
| 100 inHg | 7072.62 psf |
| 250 inHg | 17,681.6 psf |
| 500 inHg | 35,363.1 psf |
| 1000 inHg | 70,726.2 psf |
| 5000 inHg | 353,631 psf |
Exact factor: 1 inch of mercury = 70.7262047474 pounds per square foot.
| Quantity | inHg | psf |
|---|---|---|
| Sea-level air | 29.92 inHg | 2116 psf |
| A car tyre | 65.15 inHg | 4608 psf |
| Blood pressure, systolic | 4.724 inHg | 334.1 psf |
| A bicycle tyre | 183.2 inHg | 1.296e+04 psf |
| A domestic water main | 118.1 inHg | 8354 psf |
| A steam boiler | 295.3 inHg | 2.089e+04 psf |
Published reference values, converted with the same factor this page uses.