Calculating how many cubic yards of concrete to order can be
difficult since we usually think in feet and inches and not
yards. Also, areas to be filled with concrete are not always
perfect rectangles. Often they are irregular shapes with angled
sides,. Most areas to be filled with concrete can be divided
into rectangles, triangles, and pier holes (circles or columns).
The drawing at the bottom of this page shows a driveway, walkway,
and stepping stone as an example. This calculator provides entries
for each of these three main shapes. Each shape needs certain
dimensions and a depth. You may enter your dimensions in feet,
inches, or both feet and inches. The calculator computes the
volume of each shape and converts it to cubic yards.
The calculator provides rows for you to enter the information
for each of your shapes. Enter the dimensions in feet, inches,
or both. When you select the calculate button, each area will
have the cubic yards calculated and the totals for all areas
will be shown at the bottom of the form.
Shapes:
Rectangles are defined by width, length, and depth
Triangles are defined by the length of each of the three sides
(A, B, C) and depth
Pier holes (columns or circles) are defined by diameter and
depth
Totals:
Cubic Yards = The number of cubic yards computed for the
shape entered
Total Yards = The actual number of yards computed
Add for error = Apercentage to add (default 5%) to the total
to allow for computational error and uneven excavation
Adjusted Yards = The Total Yards +computed error adjustment
Yards to order = Adjusted yards rounded up to next yard (Concrete
is sold in whole yards.)
Buttons:
Calculate  Calculates Cubic Yards for each area and totals
at the bottom
Clear  Clears all values including the "add for error"
field
Help  Brings you to this screen
An example:
Let's assume that you have a driveway that is 9 feet wider at
the street than at the garage door, a circular stepping stone
between the driveway and a rectangular walkway. You subdivide
the driveway to get one rectangle and two triangles. All the
areas will be 4 inches deep.
Rectangle 1 Sidewalk 
29' x 2' 6" x 4"

Rectangle 2 Drive 
29' x 17' x 4"

Triangle 1 Drive 
29' x 4' 5" x 29' 4" x 4"

Triangle 2 Drive

29' x 4' 5" x 29' 4" x 4"

Column Circle 
3' 6" x 4"

