CONCRETE GRADES
Concrete Strength Grades (psi)
In the US, concrete is specified by f′c — the specified 28-day compressive strength, in psi, of a standard test cylinder. The grade drives the strength-based water-cement ratio and typical uses below.
Choose a grade
Grades at a glance
| f′c | Approx. metric | Typical uses |
|---|---|---|
| 3000 psi | ~20.7 MPa | Footings, foundation walls, non-structural slabs, general residential work |
| 4000 psi | ~27.6 MPa | Driveways, structural slabs, most commercial / structural work, exterior flatwork |
| 5000 psi | ~34.5 MPa | Columns, beams, heavily loaded members, high-durability applications |
Higher strength grades need a lower water-cement ratio and usually more cement. See the method page for how w/c is selected.
Frequently asked questions
What does psi mean?
Pounds per square inch — the unit for f′c, the specified 28-day compressive strength measured on a standard cylinder.
Which grade for a driveway?
4000 psi is commonly used for driveways and exterior flatwork, but always confirm the required grade against local codes and project specifications.