100 psi to mmHg — 100 pounds per square inch in millimetres of mercury
Exact 100 × 51.714925 = 5,171.49
100 pounds per square inch in other units
| Pascals | 689,475.73 | Pa |
|---|---|---|
| Hectopascals | 6,894.76 | hPa |
| Kilopascals | 689.475729 | kPa |
| Megapascals | 0.68947573 | MPa |
| Millibars | 6,894.76 | mbar |
| Bar | 6.894757 | bar |
| Standard atmospheres | 6.804596 | atm |
| Torr | 5,171.49 | Torr |
| Millimetres of mercury | 5,171.49 | mmHg |
| Inches of mercury | 203.602068 | inHg |
psi to mmHg at a glance
| Pounds per square inch | Millimetres of mercury |
|---|---|
| 1 psi | 51.714925 mmHg |
| 2 psi | 103.42985 mmHg |
| 3 psi | 155.144776 mmHg |
| 5 psi | 258.574626 mmHg |
| 10 psi | 517.149252 mmHg |
| 20 psi | 1,034.3 mmHg |
| 25 psi | 1,292.87 mmHg |
| 50 psi | 2,585.75 mmHg |
| 100 psi | 5,171.49 mmHg |
| 250 psi | 12,928.73 mmHg |
| 500 psi | 25,857.46 mmHg |
| 1,000 psi | 51,714.93 mmHg |
How to convert pounds per square inch to millimetres of mercury
Multiply by 51.714925 — one pound per square inch is 51.714925 millimetres of mercury. That factor is exact: it comes from the definition of the units rather than from a measurement, so it will not change and does not need rounding.
Working 100 × 51.714925 = 5,171.49
In words: about five thousand one hundred seventy-one millimetres of mercury.
What these units are
The pound per square inch and the millimetre of mercury are covered in the pressure unit guide, along with every other unit on this page.
Questions
How many millimetres of mercury are in a pound per square inch?
One pound per square inch is 51.714925 millimetres of mercury. This figure is exact — it comes from the definition of the unit, not a measurement.
What is 100 pounds per square inch in millimetres of mercury?
100 pounds per square inch is 5,171.49 millimetres of mercury. The working is 100 × 51.714925 = 5,171.49.
What pressure should my tyres be?
Look at the sticker in the driver's door frame or the fuel flap, not the number moulded into the tyre — that one is the tyre's maximum, not the manufacturer's recommendation. Most cars sit somewhere around 32 to 35 psi, which is roughly 2.2 to 2.4 bar.
Is my tyre gauge measuring absolute or gauge pressure?
Gauge pressure — the amount above the surrounding air. A tyre reading 32 psi actually contains about 46.7 psi absolute, because atmospheric pressure of roughly 14.7 psi is already pressing on the other side of the gauge. Conversions on this page are between units, and leave that distinction alone.
Why do weather forecasts use hectopascals and millibars interchangeably?
Because they are the same size. One hectopascal is exactly one millibar, so the change from mbar to hPa was a relabelling rather than a conversion. Standard sea-level pressure is 1013.25 of either.
What is the difference between torr and mmHg?
Almost nothing, and the difference is deliberate. A torr is exactly one seven-hundred-and-sixtieth of a standard atmosphere; the conventional mmHg is defined as exactly 133.322387415 pascals. They diverge by about one part in seven million — invisible in medicine, occasionally not in vacuum work.