Calculate how much concrete it will take in both cubic yards and how many of any size bags. Both are returned when values for the length, width, and depth are entered.

Concrete Yardage Calculator

• Enter the width, length, and depth in feet and inches, or simply inches.
• The number of cubic yards is automatically returned just below.
• Select a size for the bags and their number is returned.
• For a bonus, the weight of the concrete is also returned.
• Due to the nature of lumber sizes, the thickness of a slab is controlled by the dimensions of the forming material. For a 4″ thick slab 2 x 4’s are usually used for the forming material. While they are technically only 3 1/2″ wide, still round up to 4″ in the thickness field. Its better to have a little left over than not enough.

Monolithic Slabs

Monolithic slabs are mostly used for shops, garages, and other buildings like that. They have the advantage of pouring the footing and the slab at the same time. Its all one big hunk of concrete when its finished. To solve for the cubic yards needed, simply break the pour down into rectangular prisms.

• Start with the slab. However thick is is away from the footings, use that depth. The width and length will the same as the overall dimensions of the floor. Write down the volume.
• Now for the footings. Many footings on monolithic slabs do not have rectangular cross sections at all. The inside is often quite tapered because of the nature of the gravel or other fill material. Find an average and use that. For example if the footing is 1′ wide at the bottom, and its 3′ wide at the top, then use 2′ for the width.
• As for the length, simply use the entire perimeter.
• Subtract the thickness of the slab for the depth.
• Add this result to the volume for the slab and the result is the total number of cubic yards needed.

Pillars & Columns

It may be better to use this post hole volume calculator for a more accurate calculation. Or you can simply treat the pillar or column like it’s cross section is square and then multiply by .78.

Don’t Forget

This tool is only as accurate as the numbers entered into it. It can be more difficult than it would seem to enter in reliable numbers when measuring them in the field under scrutiny. There will probably be only a limited amount of time available to to take any measurements periods. That’s simply because many builders expect that you know the basic dimensions. Do not be fooled by any behavior which would cause unreliable field results.