Estimated Concrete Volume
3.5 cubic yards
94.5 cubic feet
Estimated Weight of Concrete
6.28 tonsCovering 189 sq. ft. at 6" depth
for waste allowance
10% = 0.35 cubic yards
Total Concrete with 10% = 3.85 cubic yards
How Many Concrete Bags?*
|210||60lb Concrete bags|
|158||80lb Concrete bags|
|47.3||Small wheelbarrow loads|
|23.6||Large wheelbarrow loads|
Concrete Truck for 9'x21' x6"
Cost Estimate for 9'x21' x6"
Bag Cost Estimate
Truck Cost Estimate
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.So for a 10 cu/yd Truck Load - 3.5 cu/yd concrete = 6.5
6.5 x $17.00 = $110.50
$378.77 + $110.50 = $489.27
Pros Do Everything*
|$945.00||$5.00 sq ft Low End**|
|$1,134.00||$6.00 sq ft|
|$1,323.00||$7.00 sq ft|
|$1,512.00||$8.00 sq ft|
|$1,984.50||$10.50 sq ft High End***|
*6 inch pours and under.
**Cost assumes subbase and general prep is done.
With a brief look, a 9x21 area at 6 inches deep, you would need approximately 4.97 tons or 3.5 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 189 sq ft area, this may roughly cost $105.84 for wire mesh, $567.00 for thicker wire rebar mesh and $24.57 for fiber mesh.*Reinforcing for 10 inch pours and under.
6 / 12 = 0.5 ft depth
189 * 0.5 = 94.5 cu ft
94.5 / 27 = 3.5
= 3.5 cu/yd
How to Calculate Concrete Weight
3.5 * 3590 = 12565 lbs
Density of concrete used 2130 kg/m3or 133 lbs/ft3.
9 ft x 21 ft x 6" Concrete Summary
How many concrete bags would I need for a 9 ft x 21 ft x 6" slab? 158 x 80lb Concrete bags.
How much does it cost to pour a 9'x21' x6" slab? Ready-mix costs approx $489.27.
How much does it cost to hire a contractor to concrete a 9'x21' x6" slab? A pro costs between $945.00 and $1,984.50.
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 Concrete calculator can be used for a slab, floor, garage, block, wall, driveway, patio, countertop, footings, foundation, pool or basement, and most rectangular areas.