Concrete in Rectangle Slab

The Concrete in Rectangle Slab calculator computes the volume of concrete in a rectangle (square) slab. 

INSTRUCTIONS: Choose units and enter the following:

• (L) Length of Slab
• (W) Width of Slab
• (D) Depth of Slab

Volume of Concrete (V): The calculator returns:

• V - Volume of concrete in cubic yards, and the equivalent volume in number of:
  • 40lb bags
  • 60lb bags
  • 80lb bags
• A - Surface Area of the slab in square feet.
• Wtr - Water needed for concrete in gallons
• FB - Length of the form boards in feet.

However, these can be automatically changed to compatible units via the pull-down menu.  

Retail Concrete Price Survey:

• Date: 6/17/24
• Store: MULTIPLE
• Manufacturer: MULTIPLE
  • 80 lb bag: $5.06
  • 60 lb bag: $4.69

The Math / Science

The Volume of Concrete in a Slab calculator compute the volume (3 dimensional space) of a concrete slab through the following equation:

        V = L ⋅ W ⋅ D

where:

• V = volume
• L = Length of Slab
• W = Width of Slab
• D = Depth of Slab

The calculator converts the parameters into feet and computes the volume in cubic feet.  It then uses the cubic feet to return volume in cubic yards for bulk concrete delivery, and divides it by the volume of the different sizes of concrete in bags.  The most common are 40lb, 60lb and 80lb bags.

Masonry Calculators:

• Cubic Yards in a Rectangle Slab: This computes the volume of concrete in a rectangular shaped slab.
• Volume of a Polygon Slab: This computes the volume of concrete in a polygon shaped slab (e.g., pentagon or octagon) 
• Square Feet of a Rectangle Slab: This computes the surface area of rectangular shaped slab.
• Length of Rebar in a Rectangle Slab: Computes the length of rebar in a rectangular shaped slab.
• Weight of Rebar in a Rectangle Slab: Computes the weight of rebar in a rectangular shaped slab.
• Weight of Concrete by Cubic Yards:  This computes the weight of any volume of concrete.
• Weight of Concrete and Rebar in a Slab

Rebar and Slab Calculators:

• Rebar Calculator (Spanish Version: Calculadora de Barras de Refuerzo)
• Weight of Any Volume of Concrete 
• Rebar and Concrete Volume and Weight in a Slab
• Rebar Weight
• Length of Rebar needed for a slab.
• Weight of Rebar in a slab.
• Weight, Volume of Concrete and Surface Area of a Concrete Slab
• Surface Area of a slab
• Surface Area of Concrete Forms. 
• Volume of Concrete in a slab. 
• Water Needed for Concrete
• Rebar and Concrete in a Slab
• Length of Rebar in Grid
• Weight of Rebar in Grid
• Rebar in a Wall
• Rebar in an Irregular Shaped Slab
• Rebar in a Circular Slab
• Rebar Lapping Length
• Rebar Cost Estimate
• Weight of Length of Rebar 
• Concrete Displaced by Rebar
• Total Weight of a Slab with Rebar

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.