The Masonry Calculator contains equations and data used in working Rectangular Slab
Non-Squared Shapes
8 sided polygon (octagon) slab
with concrete slabs, walls and piers and footers, bricks, blocks and concrete walls. The formulas in this calculator are generally used to calculate materials needed for slabs of different shapes (e.g. rectangular, circular, or polygons), masonry walls made of poured concrete, brick or block, and columns and peers. It also includes a calculator to compute the delivery cost of bulk concrete. For more comprehensive rebar (reinforcement bar) calculations, see the Rebar Calculator.
Slab Functions
- Rebar and Concrete in a Slab - For a rectangular slab, this computes the:
- Length of Rebar
- Weight of Rebar
- Volume of Concrete (this take into account concrete displace by rebar)
- Weight of Slab (Rebar and Concrete)
- Concrete of Concrete in a Slab - This computes the volume for a rectangular slab:
- Volume of Concrete in Cubic Yards
- Equivalent Volume in number of 40 lb, 60 lb and 80 lb bags.
- Surface Area of Slab
- Length of Form Boards
- Water needed for concrete..
- Cubic Yards in a Circular Slab - This computes:
- Cubic Yards of Concrete
- The equivalent volume in 80lb, 60lb and 40lb bags of concrete
- Surface Area of the Circular Slab
- Perimeter of the Circular Slab
- Cubic Yards in a Polygon Slab - This computes
- Cubic Yards of Concrete
- The equivalent volume in 80lb, 60lb and 40lb bags of concrete

- Surface Area of the Polygon Slab
- Weight of Concrete by Cubic Yards - This computes the weight of a volume of concrete
- Weight of Rebar - This computes the weight of a length of rebar based on the rebar size
- Price of Delivered Concrete - This computes the price of delivered concrete based on the volume, price per cubic yard, pumping cost, delivery distance, and mileage.
Walls, Footers and Columns(piers) Functions
Foundations - Footers - Piers
Pricing Information
Retail Concrete Price Survey:
General Information
Sea sand is usually discouraged when mixing concrete. The salt content of the sand weakens the concrete and shortens the life of the concrete structure.
Guidelines for Depth of Concrete Slabs

Always consult local building codes for the best answer. However, a guideline for the depth of concrete is as follows:
4” - Home basement floors, farm building floors
4”-5” - Home garage and porches
5”-6” - Sidewalks, barn and granary floors, small sheds
6”-8” - Driveways
See Also