PSI to MPa Converter
1 psi = 0.006894757 MPa. Type in either box.
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Where materials meet hydraulics
Megapascals and psi are the two units used for the pressures and stresses that matter in engineering: hydraulic circuits, concrete strength, tensile strength, burst ratings. Which one a datasheet uses depends almost entirely on where it was written.
1 MPa = 145.0377 psi
A useful anchor is that one megapascal is about 145 psi, and about ten atmospheres. Concrete rated at 30 MPa is roughly 4,350 psi; a hydraulic system at 3,000 psi is about 20.7 MPa.
A megapascal is also exactly one newton per square millimetre, which is why structural engineers can read MPa and N/mm² as the same number.
Pounds per square inch
PSI is one pound of force spread over one square inch. It is the everyday pressure unit in the United States and still widely used in Britain for tyres, and it is defined exactly, because both the pound-force and the inch are defined exactly.
Almost every psi figure you meet in daily life is gauge pressure — pressure above atmospheric, sometimes written psig. A tyre at 32 psi holds 32 psi more than the air around it, not 32 psi in total.
The megapascal
A million pascals, used where pressures and stresses are large: hydraulics, material strength, concrete. One megapascal is almost exactly ten atmospheres, which makes it a convenient size for engineering.
A megapascal is also identical to a newton per square millimetre, which is why materials datasheets quote tensile strength in MPa and structural drawings in N/mm² without anyone needing to convert.
The working, step by step
Every line updates with whatever you type above. The point is the method, which is the same for any pair of units in this family.
The same quantity, two different numbers
One physical amount, read off two scales. The tick marks do not line up, and the gap between them is the conversion factor made visible.
How much is that?
A number is easier to judge next to something familiar.
Your turn
Reading a method and being able to use it are different things. Answer within half a per cent and it counts as correct.
Score: 0 of 0
How to use this converter
- Type into either box. The other side updates as you go; there is no button to press.
- Swap the direction with the button between the boxes, carrying your value across.
- Set the decimals if the default is more or less precision than you need.
- Copy the answer with its unit, ready to paste.
- Use the shortcut buttons for the values that come up most often.
- Share the result. The address bar tracks what you type, so the link you copy opens on the same number.
Common uses and tips
Where pressure conversions come up
- Tyres. The single most common reason anyone converts pressure. American placards are in psi, European and Asian ones in bar or kPa, and the three appear side by side on the same door sticker.
- Weather. Forecasts use hectopascals or millibars, which are the same size — 1 hPa is 1 mbar. A typical high-pressure system reads about 1020 of either.
- Diving. Cylinder pressures are in bar almost everywhere and psi in the United States. A full 200 bar cylinder is about 2,900 psi.
- Coffee. Espresso machines are specified in bar; nine bar at the group head is the usual target, which is about 130 psi.
- Materials and hydraulics. Tensile strength and hydraulic ratings come in MPa or psi, and the two communities rarely use the same one.
The trap: gauge pressure and absolute pressure
Almost every pressure you read off a dial in daily life is gauge pressure — how much higher than the surrounding air it is. A tyre at 32 psi contains 32 psi more than the atmosphere, so its absolute pressure is about 46.7 psi.
Conversion between units never changes which of the two you have. If you start with a gauge reading you end with a gauge reading. Where it goes wrong is in physics and chemistry, where the gas laws need absolute pressure: add one atmosphere to a gauge figure before it goes into a calculation. The units psig and psia exist precisely to keep the two apart.
Tips worth knowing
- One bar is not one atmosphere. It is 0.9869 of one. The difference is small enough to ignore for a tyre and large enough to matter in a laboratory.
- Millibars and hectopascals are identical. Weather maps use whichever the local service prefers; the number is the same.
- One MPa is about ten atmospheres, which makes megapascals easy to sanity-check against everyday pressures.
- Torr and mmHg are interchangeable in practice, differing by about one part in seven million.
Values people look up most
Each one opens the converter with the number already in it.
- 100 psi to MPa
- 145 psi to MPa
- 200 psi to MPa
- 500 psi to MPa
- 1,000 psi to MPa
- 1,500 psi to MPa
- 2,000 psi to MPa
- 2,500 psi to MPa
- 3,000 psi to MPa
- 3,500 psi to MPa
- 4,000 psi to MPa
- 4,350 psi to MPa
- 5,000 psi to MPa
- 6,000 psi to MPa
- 8,000 psi to MPa
- 10,000 psi to MPa
Quick reference
| PSI | Megapascals |
|---|---|
| 100 psi | 0.689476 MPa |
| 145 psi | 0.99974 MPa |
| 500 psi | 3.447379 MPa |
| 1,000 psi | 6.894757 MPa |
| 2,000 psi | 13.789515 MPa |
| 3,000 psi | 20.684272 MPa |
| 4,350 psi | 29.992194 MPa |
| 5,000 psi | 34.473786 MPa |
| 10,000 psi | 68.947573 MPa |
| 15,000 psi | 103.421359 MPa |
Questions people ask
What is the formula for psi to MPa?
Divide by 145.0377, or multiply by 0.006894757.
How many psi is 1 MPa?
145.0377 psi. For rough work, 145 is close enough.
Is 1 MPa the same as 1 N/mm²?
Yes, exactly. A megapascal is a million newtons per square metre, which is one newton per square millimetre.
Does this convert gauge or absolute pressure?
Whichever you put in. Converting units does not change which kind of pressure you have — a gauge reading converts to a gauge reading. If a calculation needs absolute pressure, add one atmosphere first.