# How Many Yards of Concrete for a 24 x 24 Slab?

_Published October 8, 2026_

**In short:** A 24 by 24 foot slab (576 square feet) poured 4 inches thick needs 7.11 cubic yards of concrete. With 10% extra, order about 8 cubic yards. At 5 inches order about 10 yards and at 6 inches about 12 yards.

## Concrete needed for a 24 x 24 slab

A 24 × 24 slab is the standard footprint of a two-car garage. The slab is **576 square feet**. Ready-mix is sold by the cubic yard, so multiply the area by the thickness in feet and divide by 27.

```
cubic yards = 24 × 24 × (thickness in ÷ 12) ÷ 27
```

At 4 inches thick: 576 × 0.3333 = 192.0 cubic feet, and 192.0 ÷ 27 = **7.11 cubic yards**. Add 10% and the number to order is 7.82, which most suppliers will round to **8 yards**.

## 24x24 slab concrete chart

| Thickness | Exact yards | With 10% extra | Round to order | Approx. weight |
| --- | --- | --- | --- | --- |
| 4 in | 7.11 | 7.82 | 8 | 15.6 tons |
| 5 in | 8.89 | 9.78 | 10 | 19.6 tons |
| 6 in | 10.67 | 11.73 | 12 | 23.5 tons |

Fresh concrete weighs about 2 tons per cubic yard (roughly 4,000 lb), which matters for truck access and for any driveway, lawn or sewer line the truck must cross.

## Thickness for this slab

Garage floors are usually 4 to 6 inches thick, with a thicker or reinforced edge; ask your building department for the required spec. Each extra inch of thickness adds about 1.78 cubic yards to this slab, so a small change in the spec moves the order noticeably.

## Ordering from a ready-mix plant

- Most plants sell in half-yard steps above a minimum load, and charge a short-load fee for small orders, so ask for the total delivered price.
- Tell the dispatcher the slab size, thickness and the exposure (freeze-thaw, de-icing salt) so they quote a suitable mix.
- Have forms, base and finishing tools ready before the truck arrives; discharge time is limited.
- If you are close to a round number, order the larger one. Running short mid-pour leaves a cold joint.

Check other sizes with the [concrete calculator](../../concrete-calculator/), see the cost with the [concrete cost calculator](../../concrete-cost-calculator/), or measure an odd shape with the [square footage calculator](../../square-footage-calculator/).

## Common mistakes

- Ordering the exact volume and running short on a high spot.
- No clear path for the truck, or no plan for washing out the chute.
- Pouring in very hot, cold or rainy weather without a plan.
- Not asking about the mix design when the slab will see freezing and salt.

## Other sizes

[How Many Yards of Concrete for a 20x20 Slab](../how-many-yards-of-concrete-for-a-20x20-slab/) · [How Many Yards of Concrete for a 10x20 Slab](../how-many-yards-of-concrete-for-a-10x20-slab/)

## Frequently asked questions

### How many yards of concrete do I need for a 24x24 slab at 4 inches?

7.11 cubic yards exact, and about 8 yards to order with 10% extra.

### How many yards for a 24x24 slab at 6 inches?

10.67 cubic yards exact, or about 12 to order.

### How many bags of concrete are in a yard?

About 45 bags of 80 lb mix, 60 bags of 60 lb, or 90 bags of 40 lb make one cubic yard.

### How much does a concrete truck hold?

A standard ready-mix truck carries about 8 to 10 cubic yards, so this slab fits in one load.

### What is a typical slab thickness?

Four inches is common for patios and walks; garages and driveways are often 5 to 6 inches. Follow your local code.

## Sources and further reading

- [Concrete driveways and slabs](https://www.cement.org/cement-concrete/paving/buildings-structures/concrete-homes/products/driveways) — American Cement Association
- [National Ready Mixed Concrete Association](https://www.nrmca.org/) — NRMCA: ready-mix industry resources
- [NIST Special Publication 811: conversion factors](https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors) — National Institute of Standards and Technology