What this converter does
This converter turns concrete and material compressive strength in megapascals into pounds per square inch and back. It also covers ksi, N/mm² and kg/cm². Type a value, pick your units, and read the result as you type — no button needed.
A megapascal is exactly one newton per square millimetre, and a psi is defined from the pound-force and inch, so the factor is exact. For structural steel stress in ksi, see the psi to MPa converter.
The units it covers
Compressive strength is a stress — force per unit area — so every unit converts through the megapascal with a fixed ratio.
View all units & their values
| Unit | Symbol | Value | Mainly used |
|---|---|---|---|
| Megapascal | MPa | 1 | SI concrete strength (= N/mm²) |
| Pound per sq inch | psi | 0.006895 | US concrete strength |
| Kip per sq inch | ksi | 6.895 | US steel / high strength |
| Newton per mm² | N/mm² | 1 | Identical to MPa |
| Kg-force per cm² | kg/cm² | 0.09807 | Older metric / site tests |
The formula
Each unit has a fixed value in megapascals, so converting is one multiplication through the MPa:
result = value × factor_from ÷ factor_toWhere:
- value = the strength you typed, in the “from” unit
- factor_from = the “from” unit’s value in MPa
- factor_to = the “to” unit’s value in MPa
Worked example
Convert 30 MPa (a common concrete grade) to psi.
1 psi = 0.00689476 MPa30 ÷ 0.00689476 = 4351 psiSo C30 concrete is roughly 4350 psi.
The units in this example
The SI unit of stress and pressure, equal to one newton per square millimetre. Standard for concrete grades (C25, C30, C40) worldwide.
- 1 MPa = 145.0 psi
- 1 MPa = 1 N/mm²
- 1 MPa ≈ 10.20 kg/cm²
- 1 ksi = 6.895 MPa
The US customary unit of pressure and stress. Concrete strength is specified in psi (3000, 4000, 5000 psi) across North America.
- 1 psi = 0.006895 MPa
- 1000 psi = 6.895 MPa
- 1 psi ≈ 0.0703 kg/cm²
- 1 ksi = 1000 psi