What this calculator does
This pressure unit converter handles the full range of units pressure and stress get quoted in, from the pascal, kilopascal and megapascal used in engineering and materials specifications, through to bar, standard atmospheres, PSI, ksi and torr used in everything from tyre pressure to vacuum equipment and material strength ratings.
Pick the unit you have and the unit you need, and it converts in either direction. Because a megapascal calculation often needs checking against several other units at once, every supported unit is also listed alongside the converted figure, so you are not stuck converting one pair at a time.
The formula
Every unit is converted through pascals as a common base: the value entered is multiplied by its unit's fixed conversion factor to get pascals, then divided by the target unit's factor to get the answer in that unit. The same base-value trick produces the full table of equivalents shown alongside the main result.
| Term | Meaning |
|---|---|
| Pascal (Pa) | The SI base unit of pressure, defined as one newton of force per square metre. |
| Megapascal (MPa) | One million pascals, the standard unit for material strength and stress specifications such as concrete or steel ratings. |
| PSI | Pounds-force per square inch, the common imperial pressure unit used for tyres, hydraulics and plumbing in the US. |
| Bar and atmosphere | Two units close to typical sea-level air pressure: one bar is defined as exactly 100,000 pascals, and one standard atmosphere is 101,325 pascals. |
The inputs explained
| Field | What to enter |
|---|---|
| Value | The pressure or stress value you want to convert. |
| From | The unit your value is currently expressed in. |
| To | The unit you want the value converted into. |
When to use it
Reading a material strength rating
A steel or concrete specification quotes strength in megapascals, but a reference table or supplier quote uses PSI. Converting between the two confirms whether the material meets the required rating.
Checking a tyre or hydraulic pressure
Equipment manuals from different countries mix PSI, bar and kPa. Converting a stated pressure into the unit your own gauge reads avoids over or under-inflating or over-pressurising a system.
Comparing a lab or industrial pressure reading
Vacuum and lab equipment is often specified in torr or atmospheres, while a process control system might read out in kilopascals. Converting puts both readings on the same footing.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
Megapascal converted to other common pressure units
A range of megapascal values converted to PSI, the unit most often needed alongside it.
| Megapascals (MPa) | Converted value |
|---|---|
| 1 MPa | 145.0377 psi |
| 5 MPa | 725.1887 psi |
| 10 MPa | 1,450.3774 psi |
| 25 MPa | 3,625.9434 psi |
| 50 MPa | 7,251.8869 psi |
| 100 MPa | 14,503.77 psi |
| 250 MPa | 36,259.43 psi |
PSI converted to bar and kilopascals
Common PSI values converted through the same base-pascal method.
| PSI | Converted value |
|---|---|
| 15 psi | 1.0342 bar |
| 30 psi | 2.0684 bar |
| 32 psi | 2.2063 bar |
| 35 psi | 2.4132 bar |
| 60 psi | 4.1369 bar |
| 100 psi | 6.8948 bar |
| 150 psi | 10.3421 bar |
Questions
What is a megapascal used for?
Megapascals are the standard unit for reporting the strength of materials such as concrete, steel and other structural materials, and for hydraulic and pneumatic system ratings in metric-unit countries.
How many PSI is one bar?
One bar is approximately 14.5 PSI. It is also very close to atmospheric pressure at sea level, which is why bar is a convenient round-number unit for everyday pressure gauges.
What is the difference between ksi and PSI?
Ksi is simply one thousand PSI, used to keep the numbers manageable when reporting high stress values such as the tensile strength of metals, which often run into the tens of thousands of PSI.
Why does the table show every unit at once?
A single conversion is often not enough when a job involves cross-checking a rating against more than one reference source, so the full table saves converting the same figure repeatedly one unit pair at a time.
For a narrower ksi-to-megapascal only conversion, see the KSI to MPa converter. For tyre pressure specifically in kPa, PSI and bar, see the kPa to PSI tyre pressure converter.