Enter the size of your slab, patio or post holes to see how many cubic yards or bags of concrete you need and what ready-mix costs. A 20 by 10 ft patio at 4 inches thick takes about 2.5 cubic yards, or 2.7 with 10% extra.
Estimated cost
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How this calculator works
For a slab, volume is length times width times thickness (inches divided by 12), in cubic feet. Divide by 27 to get cubic yards. For round holes, it uses pi times the radius squared times the depth. An 80 lb bag makes about 0.60 cu ft, a 60 lb bag about 0.45 and a 40 lb bag about 0.30.
What changes the cost
- Ready-mix price. About $110 to $165 per cubic yard before delivery fees.
- Short loads. Orders smaller than a full truck (about 9 to 10 yards) often carry a fee of roughly $40 to $60 per missing yard.
- Labor. Hiring a crew to pour and finish a slab adds about $8 to $18 per sq ft.
- Extras. Weekend delivery, long unloading waits and fuel surcharges add more.
Where the prices come from
The starting prices are U.S. national installed ranges from 2025 and 2026 cost guides. Open Edit the prices in the calculator to replace any of them with the numbers from your own quote.
- LawnLove: concrete cost 2026 (ready-mix, pouring)
- InvoiceOwl: concrete calculator (short-load fees, bags)
Common questions
How many bags of concrete make a cubic yard?
About 45 bags of 80 lb, 60 bags of 60 lb, or 90 bags of 40 lb.
When should I order a truck instead of bags?
Past about one cubic yard, ready-mix is usually cheaper and far less work than mixing dozens of bags by hand.
How thick should a concrete slab be?
4 inches is standard for patios, walkways and garage floors. Driveways are often 4 to 6 inches.