Concrete is priced per cubic yard, but you think in square feet. Your patio is 20x15 feet, your driveway is 40x12 feet, and you have no idea how many cubic yards that requires or what it should cost. Contractors know exactly how to calculate this, and some of them use that information asymmetry to their advantage.
Knowing the math protects you from overpaying.
Concrete volume calculation
One cubic yard of concrete fills 27 cubic feet (3x3x3). To find how many cubic yards you need:
Volume (cubic yards) = Length (ft) x Width (ft) x Thickness (ft) / 27
A 20x15 foot patio at 4 inches thick:
20 x 15 x 0.333 / 27 = 3.70 cubic yards
A 40x12 foot driveway at 5 inches thick:
40 x 12 x 0.417 / 27 = 7.41 cubic yards
Always round up to the next half yard. Running short mid-pour is a disaster -- you cannot add concrete to a partially set slab without a cold joint that will crack. Order 3.70? Get 4. Order 7.41? Get 8.
Most concrete suppliers have a minimum delivery of 1 cubic yard and charge a short-load fee for orders under their minimum (typically 3-5 yards). If you need 2 yards, you might pay the same as someone ordering 3.
Cost breakdown
Ready-mix concrete in 2025 costs approximately $130-$175 per cubic yard for standard 4000 PSI mix, depending on your region. That is just the material delivered to your site.
The total project cost includes:
Concrete material: $130-$175 per yard
Delivery fee: $0-$75 (often waived above minimum order)
Short-load fee: $40-$100 per yard below minimum
Pump truck (if needed): $200-$500 (required when the truck cannot get close enough to pour directly)
Labor for finishing: $5-$12 per square foot
Rebar or wire mesh: $0.50-$1.50 per square foot
Form work: $1-$3 per linear foot
Gravel base: $1-$3 per square foot
Excavation: $2-$5 per square foot (if removing existing surface)
For that 300 square foot patio:
- Concrete (4 yards): $600
- Finishing labor: $2,100 (at $7/sqft)
- Rebar mesh: $300
- Forms: $210 (70 linear feet at $3)
- Gravel base: $450
- Total: approximately $3,660
The material is only about 16% of the total cost. Labor dominates. This is why DIY concrete work saves so much money if you have the skills, and why comparing only material quotes between contractors is meaningless.
Thickness matters more than you think
Going from 4 inches to 6 inches adds 50% more concrete but dramatically increases the slab's load capacity. For a patio that only supports foot traffic and furniture, 4 inches is standard. For a driveway that supports vehicles, 5-6 inches is minimum. For heavy vehicles or commercial loads, 6-8 inches.
The cost difference between 4-inch and 6-inch on a 300 sqft patio is about 2 more cubic yards of concrete ($300 more in material, roughly $800 more total with labor). But a 4-inch driveway under car traffic will crack within a few years. The "savings" of going thin is a future replacement cost.
PSI ratings explained
Concrete strength is measured in PSI (pounds per square inch). Common mixes:
- 2500 PSI: Footings, non-structural applications
- 3000 PSI: Sidewalks, patios, residential foundations
- 4000 PSI: Driveways, garage floors, commercial floors
- 5000+ PSI: Commercial structures, high-load applications
Higher PSI concrete costs $5-$15 more per yard. For a driveway, the $30-$60 upcharge for 4000 PSI over 3000 PSI is trivially cheap insurance against premature cracking.
Estimating your project
The interactions between area, thickness, PSI, reinforcement, and local pricing make concrete estimation surprisingly complex. I built a concrete cost calculator that computes volume, material cost, and total project cost estimates based on your specific dimensions and requirements.
I'm Michael Lip. I build free developer tools at zovo.one. 500+ tools, all private, all free.
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