How this calculator works
A ksi is one thousand pounds-force per square inch. The international pound-force on a square inch is 6,894.757293168 Pa, so one ksi is 6,894,757.293168 Pa, or 6.894757293168 MPa. Structural engineers in North America often state steel strengths in ksi, while most of the world and most concrete specifications use megapascals. Converting is a fixed multiplication because both units are defined exactly from the pound and the inch.
Formula
MPa = ksi x 6.894757293168. ksi = MPa / 6.894757293168. One ksi is exactly 1,000 psi, and one psi is 6,894.757293168 Pa.
Worked example
1 ksi = 6.89476 MPa. 36 ksi = 248.211 MPa. 50 ksi = 344.738 MPa. 100 ksi = 689.476 MPa. 0.5 ksi = 3.44738 MPa.
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Frequently asked questions
What does ksi mean?
ksi means kilopounds per square inch, or one thousand pounds-force per square inch. The k is the kilo prefix and the i and s stand for inch and square. A related unit, the kip per square inch, has the same numeric value because a kip is 1,000 pound-force.
Why do engineers use ksi instead of psi?
Steel strengths run into tens of thousands of psi, so a unit 1,000 times larger keeps the numbers short. A yield strength of 50,000 psi is 50 ksi. The same economy of digits is why megapascals are used instead of pascals.
Is ksi a pressure or a stress?
The unit has the same dimensions as pressure, a force per area. In a material it is called stress, and the number can be tensile or compressive. This converter treats it as a signed scalar and does not apply a sign convention.
How do I convert ksi to psi?
Multiply by 1,000. For example, 36 ksi is 36,000 psi. The psi to ksi page on this site does the reverse conversion with the same exact factor.