What PSI Concrete Do I Need?

PSI, pounds per square inch, is concrete's compressive strength rating at 28 days. Higher PSI resists more load and weather. Your ready-mix supplier will ask for it, and matching it to the job saves money without sacrificing durability.

PSI by project type

2,500 PSI: the practical minimum, for non-structural fill and some interior slabs.

3,000–3,500 PSI: residential slabs, patios, sidewalks, and basement floors. The everyday workhorse.

4,000 PSI: driveways, garage floors, and footings for anything carrying vehicles or structural load.

4,500–5,000+ PSI: heavy-duty, commercial, and harsh freeze-thaw exposure.

PSI is only one part of the order

Tell the supplier the strength, but also confirm exposure, air entrainment, aggregate, finish, and any reinforcing details on the plans. Local code or an engineer controls structural work; a higher PSI does not replace proper thickness, base, joints, or reinforcement. For a vehicle surface, use the driveway calculator to size the concrete and compare the reinforcement guidance with the project drawings.

PSI doesn't change the volume

Strength is about the mix, not the amount: a higher-PSI pour uses the same cubic yards, just a richer recipe. It costs a little more per yard but doesn't change the quantity you order. So size your pour with the slab calculator, then specify PSI when you call the supplier.

Don't forget air entrainment

In freeze-thaw climates, exterior concrete should be air-entrained, with tiny air bubbles that give freezing water room to expand without spalling the surface. It's a separate spec from PSI; ask for it on any outdoor pour up north. Good drainage and timely control joints matter too.

Common questions