American Contracting Exchange

Formulas, shortcuts and rule of thumb aids. This information is provided to help you check estimates. Normal estimating procedures should prevail.

AREA
Triangle = 1/2 of the base x the height
Parallelograms = (squares and rectangles) length x width
Rhomboid = height x base
Trapezoid = the sum of the parallel sides x height
Circle = diameter x circumference divided by 2
Circumference of circle = diameter x 3.1416
Circumference of circle = radius x 6.2832
Diameter of circle = circumference x .3183
Radius of circle = circumference x .159155
One Acre = 43,560 sq. ft

VOLUME
Rectangle = length x width x height
Cylinder = area of base x height
Sphere (surface) = 4 x 3.1416 x radius squared

PAINT / WALLPAPER
Coverage 350 to 400 sq. ft. per gallon
8' X 12' W/ 8' ceiling 14 single rolls

BLOCK / BRICK
8 X 8 X l6 Block 112 per 100 sq. ft.
4x 3 1/5 x8 Brick 563 per 100 sq. ft.

CONCRETE
10' X 10' Slab 4" Thick = 1 1/4 Cubic yards
Reddy mix calculator
20 sq. ft x 4" thick (14) 60#bags
Post hole 18" deep x 12" diameter (2) 80#bags

American Contracting Exchange • Office: (410) 409-4890 • FAX: (410) 877-1554
603 Millwood Drive, Fallston, MD • 21047 USA • e-mail: info@HomeRepair.org