Answer

Estimated Concrete Volume

6.667 cubic yards

180 cubic feet

Estimated Weight of Concrete

## 11.97 tons

Covering 360 sq. ft. at 6" depthChange dimensions

Optional 10% extra concrete

for waste allowance

10% = 0.67 cubic yards

Total Concrete with 10% = 7.33 cubic yards

for waste allowance

10% = 0.67 cubic yards

Total Concrete with 10% = 7.33 cubic yards

## Order Size

This order size is considered

**Large**### How Many Concrete Bags?*

399 | 60lb Concrete bags |

300 | 80lb Concrete bags |

90 | Small wheelbarrow loads |

45 | Large wheelbarrow loads |

## Concrete Truck for 18'x20' x6"

67%

**0.67 Concrete Truck Loads**(10 cu/yd Capacity)

## Cost Estimate for 18'x20' x6"

Purchasing ready-mix concrete is by far the easiest way to mix concrete for medium to large projects and can even be used on smaller projects as well. We have provided a cost comparison between ready mix and DIY concrete premix bags to give you a rough ballpark estimate.

## Bag Cost Estimate

Pre-mixed concrete bags cost on average $3.50 per 80lb bag. Using pre-mixed bags to cover 360 sq ft at a depth of 6", the estimated cost is

**$1,050.00****$1,050.00**

for 300 x 80lb bags

## Truck Cost Estimate

Ready-mixed concrete costs on average $108.22 per cubic yard delivered. Using a concrete truck to cover 360 sq ft at a depth of 6", the estimated cost is

3.3 x $17.00 = $56.10

$721.47 + $56.10 =

*6 inch pours and under.

**Cost assumes subbase and general prep is done.

**$721.47**Concrete trucks may also charge a **"short load"** fee for partially filled loads. Short load fees are charged at about $17 for every yard not used on the truck.

3.3 x $17.00 = $56.10

$721.47 + $56.10 =

**$777.57****$777.57**

### Pros Do Everything*

$1,800.00 | $5.00 sq ft Low End** |

$2,160.00 | $6.00 sq ft |

$2,520.00 | $7.00 sq ft |

$2,880.00 | $8.00 sq ft |

$3,780.00 | $10.50 sq ft High End*** |

*6 inch pours and under.

**Cost assumes subbase and general prep is done.

## Concrete Extras

A well-compacted

**subbase**provides a strong foundation for concrete to lay on. We recommend you contact your nearest concrete supplier for their recommendations on whether you need a subbase, base depth, and rock type.With a brief look, a 18x20 area at 6 inches deep, you would need approximately **9.47 tons** or **6.67 cubic yards of gravel**.

**Concrete reinforcing** is also recommended in high traffic areas and medium to large areas. **Wire mesh** on average costs **$0.56 per sq ft** and **fiber mesh** costs **$0.13 per sq ft**.

So for your **360 sq ft area**, this may roughly cost **$201.60** for wire mesh, **$1,080.00** for thicker wire rebar mesh and **$46.80** for fiber mesh.

How to Calculate Concrete Amount for 18x20 x6"

18 * 20 = 360 sq ft

6 / 12 = 0.5 ft depth

360 * 0.5 = 180 cu ft

180 / 27 = 6.6666666666667

= 6.667 cu/yd

How to Calculate Concrete Weight

6.6666666666667 * 3590 = 23933.33 lbs

Density of concrete used 2130 kg/m

6 / 12 = 0.5 ft depth

360 * 0.5 = 180 cu ft

180 / 27 = 6.6666666666667

= 6.667 cu/yd

How to Calculate Concrete Weight

6.6666666666667 * 3590 = 23933.33 lbs

Density of concrete used 2130 kg/m

^{3}or 133 lbs/ft^{3}.## 18 ft x 20 ft x 6" Concrete Summary

**How much concrete do I need for an area of 18 ft x 20 ft x 6" depth?**6.667 cu. yds.

**How many concrete bags would I need for a 18 ft x 20 ft x 6" slab?**300 x 80lb Concrete bags.

**How much does it cost to pour a 18'x20' x6" slab?**Ready-mix costs approx $777.57.

**How much does it cost to hire a contractor to concrete a 18'x20' x6" slab?**A pro costs between $1,800.00 and $3,780.00.

**How do you calculate concrete volume?**Formula ((width x length) x (depth in inches / 12)) / 27 = total cubic yards. See our how to here

**This Page is Calculated for the Following:**18 ft x 20 ft x 6", 18x20x6, 360 sq. ft., 18 x 20, 18x20, 18x20 x6", 18'

*x*20'

*x*6", 18'x20' x6"

This

**Concrete**calculator can be used for a slab, floor, garage, block, wall, driveway, patio, countertop, footings, foundation, pool or basement, and most rectangular areas.