How Many Yards of Concrete for a 24x24 Slab
A 24x24 slab is one of the most common pours in residential construction — it is the footprint of a standard two-car garage, a generous patio, or a large workshop pad. At 576 square feet it is also firmly in ready-mix territory, so getting the yardage right the first time matters. This guide gives you the exact cubic yard figure at every common thickness, explains how much waste to add, and shows what the concrete will cost in 2026.
The math behind a 24x24 slab
Concrete volume is just length times width times depth, with the depth converted from inches to feet. Because ready-mix is sold by the cubic yard, the last step divides by 27:
That single formula covers every scenario below. The only variable that changes is thickness, and thickness is driven entirely by what the slab has to carry.
Yardage by thickness: the worked numbers
Here is the full breakdown for a 24x24 pour. The "order" column adds a 10 percent waste allowance and rounds up to the nearest half yard, which is how most dispatchers will book the load.
| Thickness | Cubic Feet | Cubic Yards | Order With 10% Waste | Typical Use |
|---|---|---|---|---|
| 4 inches | 192 | 7.1 | 8.0 yd | Patio, shed floor, walkway |
| 5 inches | 240 | 8.9 | 10.0 yd | Standard garage, light vehicles |
| 6 inches | 288 | 10.7 | 12.0 yd | Driveway, workshop, trucks |
| 8 inches | 384 | 14.2 | 16.0 yd | RV pad, heavy equipment |
Notice how quickly the numbers climb. Going from 4 inches to 6 inches adds roughly 3.6 cubic yards — about half a truckload of extra material. That is a meaningful cost jump, so match the thickness to the actual load rather than over-building by default.
Why bagged concrete is not realistic here
An 80-pound bag of concrete mix yields approximately 0.60 cubic feet. A 4-inch 24x24 slab needs 192 cubic feet, which works out to roughly 320 bags. At 60 pounds per bag (0.45 cubic feet each) you would need about 427 bags. Beyond the cost, mixing that volume by hand guarantees cold joints, because you physically cannot place and finish it before earlier batches begin to set.
Bagged mix remains the right call for small footings, post bases, and repairs. For anything approaching a cubic yard, ready-mix is both cheaper and structurally better. If you are pricing out masonry work alongside the slab, our Block Calculator and Brick Calculator handle the unit counts for stem walls and edging.
How much waste should you add?
- 5 percent — clean rectangular form, level compacted base, experienced crew
- 10 percent — the safe default for most DIY and residential jobs
- 15 percent — soft or uneven subgrade, curved edges, or thickened perimeter footings
Subgrade irregularity is the single biggest driver of overage. A base that dips half an inch across the slab adds roughly 24 cubic feet — nearly a full cubic yard — on a 576 square foot pour. Screed the gravel carefully before the truck arrives.
What a 24x24 slab costs in 2026
Delivered ready-mix typically runs $150 to $200 per cubic yard across most US markets in 2026, with metro areas at the upper end and rural deliveries adding fuel surcharges. An 8-yard order for a 4-inch slab therefore lands around $1,200 to $1,600 in material alone.
Installed cost is a different number. Including excavation, gravel base, forms, reinforcement, placement, and finishing, expect approximately $7 to $13 per square foot, or roughly $4,000 to $7,500 for the full 576 square feet. Decorative finishes such as stamping or staining push that higher.
Two fees catch people out. Short-load charges apply when you order under the plant minimum — usually 3 to 5 yards — and can add $100 to $250. Standby time beyond the included 5 to 7 minutes per yard is typically billed at $2 to $4 per minute, so have your crew and tools ready before the truck rolls in.
Ordering tips that save money
Book the pour for early morning in summer to slow the set time. Confirm the truck can reach within chute distance, roughly 15 feet, or budget for a pump at $800 to $1,500 per day. Ask the plant whether they bill in quarter-yard or half-yard increments, since that determines whether 7.8 yards becomes 8.0 or 9.0 on the invoice.
Finally, decide your reinforcement plan before ordering, because a thickened edge or a heavier rebar grid can change both volume and slab depth. Browse the full set of concrete and masonry calculators to size footings, columns, and reinforcement for the same project.