Cost calculator
Concrete Slab Calculator (Bags + Cost)
Get the cubic yards, bag count, and cost for any patio, walkway, or footing pour.
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Pouring a slab? This calculator does the math you need before heading to the store or scheduling a ready-mix truck — including waste factor so you don't come up short mid-pour.
Concrete slab calculator
You'll need
1.23 cu yd · 62 bags
Volume: 33.3 cu ft (incl. 10% waste)
- Bagged mix (80 lb)$372 – $527
- Ready-mix delivery (1.5 cu yd)$210 – $300
Ready-mix is usually cheaper above ~1 cu yd. Most suppliers have a short-load fee under 3 yd.
Frequently asked
How thick should a concrete slab be?
- Walkways: 4 inches
- Patios & sheds: 4 inches
- Driveways: 4–6 inches (6+ for trucks/RVs)
- Garage floors: 4–6 inches with rebar
How many 80 lb bags in a cubic yard?
About 45 bags of 80 lb mix per cubic yard. Bagged mix gets expensive fast — for anything over ~1 cubic yard, ready-mix delivery is usually cheaper.
What is short-load fee?
Most ready-mix suppliers charge $50–$150 extra per yard short of a full load (typically 8–10 yd). Below ~3 yd, that fee can match the concrete cost.