Volume of Circular Slab

The Volume of a Circular Slab calculator computes the cubic yards (volume) of concrete a circular slab based on the diameter and depth.

INSTRUCTIONS: Choose units and enter the following:

• (D) Diameter of Slab
• (d) Depth of Slab

Volume of Concrete (V): The volume is returned in cubic yards.  The surface area (A) is returned in square feet, and the perimeter (P) is returned in feet..  However, these can be automatically converted to compatible units (e.g. cubic meters) via the pull-down menu.  The calculator also returns the equivalent volume in the number of different size bags (BG) of concrete as follows: 40lb bags, 60lb bags and 80lb bags.  Finally, the calculator returns the estimated water (WTR) requirement.

The Math / Science

The formula for the volume of a circular slab is:

V = π ⋅ (D/2)² ⋅ d

where:

• V = Volume of Circular Slab
• D = Diameter of Circular Slab
• d = Depth of Circular Slab

Circular Concrete Slab Calculators

• Rebar in Circular Slab: Computes the length and weight of rebar in a circular slab based on the dimensions, spacing, number of mats, rebar size, rebar stick length and lapping factor.
• Circular Slab Surface Area: Computes the surface area of a circular slab based on the diameter.
• Circular Slab Circumference: Computes the perimeter (circumference) of a circular slab base on the diameter.
• Volume of Circular Slab: Computes the cubic yards (volume) of concrete a circular slab based on the diameter and depth.
• Circular Slab Weight: Computes weight of a circular slab of concrete based on the diameter, depth and the mean density of concrete.
• Circular Slab Circumference from Area: Computes the circumference of a circular slab based on the surface area of the slab.
• Semi-circle Slab Volume: Computes the volume of concrete in a semicircular shaped slab based on the radius and the depth.
• Semi-Circle Slab Weight: Computes the weight or mass of a semicircular shaped concrete slab based on the radius, the depth and mean density of concrete.

Bags of Concrete Calculators

Functions and data associated with using bags of concrete in different sizes (40lb, 60lb and 80lb) to fill concrete slabs of different shapes (rectangular, round, polygon).

• Concrete Bags from Volume
  • Price of Concrete using Bags: Compute the cost of a volume of concrete (e.g., 4.2 cubic yards) using bags of concrete.
  • Concrete by 40lb bag: Computes the number of 40 pound bags of concrete and water needed to mix a volume of concrete.
  • Concrete by 60lb bag: Computes the number of 60 pound bags of concrete and water needed to mix a volume of concrete.
  • Concrete by 80lb bag: Computes the number of 80 pound bags of concrete and water needed to mix a volume of concrete.
  • Concrete Bag Volume: Computes the cubic yards of concrete that can be made from a number of bags of concrete.
• Concrete in Rectangle Slab
  • 40lb bags in a Slab: Computes the number of 40 pound bags of concrete, length of form boards, and water needed for a rectangle (square) slab based on the dimensions of the slab.  
  • 60lb bags in a Slab: Computes the number of 60 pound bags of concrete, length of form boards and water needed for a rectangle (square) slab, footer, sidewalk, driveway or curb. 
  • 80lb bags in a Slab: Computes number of 80 pound bags of concrete, length of form boards and water needed for a rectangle (square) slab. 
• Volume of Circular Slab
  • 40lb Bags a Circular Slab: Computes the volume of a circular slab and returns the number of 40 pound bags needed, the volume in cubic yards, surface area in square feet, circumference in feet, and the water requirement for making the concrete. 
  • 60lb Bags for Circular Slab: Computes the volume of a circular slab and returns the number of 60 pound bags needed, the volume in cubic yards, surface area in square feet, circumference in feet, and the water requirement for making the concrete.
  • 80lb Bags for Circular Slab: Computes the volume of a circular slab and returns the number of 80 pound bags needed, the volume in cubic yards, surface area in square feet, circumference in feet, and the water requirement for making the concrete.
• Concrete in Polygon Slab: Computes the amount of concrete (volume) in a polygon shaped concrete slab based on the diameter of the slab, number of sides (e.g., 8 for octagon), and depth.  It also returns number of bags (40lb, 60lb, 80lb), water required to make the cement, surface area, length of the individual sides and the total length of the form boards.
• Water Needed for Concrete: Computes the amount of water needed to make a volume of concrete.
• Concrete around Circular Post: Computes the volume of concrete including bags of concrete (40lb, 60lb, 80lb) around a number of round posts in a round hole based on the size of the hole and dimensions of the post. 
• Concrete around Square Post: Computes the volume of concrete including bags of concrete (40lb, 60lb, 80lb) around a number of square post (e.g., 6x6) in round hole based on the dimensions of the post, depth and width of the round hole.
• Concrete Mix: Computes volume and weight of cement, sand, gravel and water requires to make a volume of concrete.
• Data Items
  • Cubic Feet of Concrete in a 40lb bag: 0.3 ft³
  • Cubic Feet of Concrete in a 60lb bag: 0.45 ft³
  • Cubic Feet of Concrete in a 80lb bag: 0.6 ft³
  • Retail Concrete Price Survey:
    • Price Survey Date:6/17/24
    • Price Survey Online Store: MULTIPLE
    • Manufacturer: MULTIPLE
      • 80 lb bag: $5.06
      • 60 lb bag: $4.69
      • 40 lb bag: $4.25
      • 10 lb bag: $3.48

CAUTION: The pricing information provided is for calculating convenience with NO implied guarantees to the accuracy of the values listed. Authoritative sources should be sought to confirm any value before risking health or wealth on the veracity of the data. Furthermore, Calc gives no guarantee that you will be able to buy products at listed prices or even if they will be available.  The data provided is purely a convenience for making estimates, so we repeat, ALWAYS use local pricing and authoritative specifications.