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Concrete for a 8x10 Slab

A 8x10 slab (80 sq ft) 4 inches thick needs 0.99 cubic yards (26.67 cubic feet) of concrete, or 45 bags of 80 lb premix. Order about 10% extra: 1.09 cubic yards or 49 bags.

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8x10 slab: concrete by thickness

Thickness Cubic feet Cubic yards 80 lb bags 60 lb bags Order (+10%)
4 inch 26.67 0.99 45 60 1.09 yd³ · 49 × 80 lb
5 inch 33.33 1.23 56 75 1.36 yd³ · 62 × 80 lb
6 inch 40 1.48 67 89 1.63 yd³ · 74 × 80 lb
8 inch 53.33 1.98 89 119 2.17 yd³ · 98 × 80 lb

Volume = 8 ft × 10 ft × thickness in inches ÷ 12. 1 cubic yard = 27 cubic feet. Bags are rounded up.

Concrete for common slab sizes

About the Concrete Calculator

The concrete calculator works out how much concrete a job needs. Pick the shape (a slab or patio, a wall, a footing, a round column or Sonotube, fence post holes or stairs), enter the sizes in feet and inches or meters and centimeters, and it shows the cubic yards or cubic meters to order, with extra for waste, and how many premixed bags of each size that makes. Add your local prices to compare bags with a ready-mix truck.

How to use it

  1. 1 Choose the shape: slab, wall, footing, column, post holes or stairs.
  2. 2 Pick feet and inches or meters and centimeters, and enter the sizes.
  3. 3 Set how many, and the extra for waste (10% is usual).
  4. 4 Read the cubic yards to order and the number of 40, 60 or 80 lb bags; add prices to see the cost.

Frequently asked questions

How much concrete do I need for a 8x10 slab?

A 8x10 slab is 80 square feet. At 4 inches thick that is 80 × 4 ÷ 12 = 26.67 cubic feet, or 0.99 cubic yards (0.76 m³). At 6 inches it is 1.48 cubic yards. Order about 10% more, 1.09 cubic yards at 4 inches, to allow for an uneven base and spills.

How many bags of concrete for a 8x10 slab?

For a 4 inch 8x10 slab you need 45 bags of 80 lb, 60 bags of 60 lb or 89 bags of 40 lb premix, before any extra. With 10% extra that is 49 bags of 80 lb. An 80 lb bag makes about 0.6 cubic feet.

Should I use bags or ready-mix for a 8x10 slab?

Bags. A job under about one cubic yard is easy to mix by hand or in a small mixer, and a ready-mix truck would charge a short-load fee.

How thick should a 8x10 slab be?

4 inches suits patios, walkways and shed floors. Use 5 to 6 inches for a driveway, garage floor or a hot tub base, and follow local building code and your designer for anything that carries heavy loads.