How to Measure Irregular Shapes for Sod

Break the irregular shape into individual squares, triangles, circles and rectangles. Ensure that the shapes do not overlap, and then determine the area of each shape. For example, you can divide a long rectangle with semicircular ends into a rectangle and two semicircles; a "C" shaped lawn consists of three rectangles.

Multiply the length by the width to determine the area of rectangles and squares. For triangles, multiply the base width by half the height. For circles, multiply the radius squared by pi, which is 3.1415. For example, you can measure a rectangular lawn consisting of a 30- by 60-foot rectangle and a semicircular end with a radius of 15 feet as an 1,800 square foot rectangle -- 30 x 60 = 1,800 -- and a 353.42 square foot semicircle -- (3.1415 x (15 x 15)) / 2 = 353.42.

Combine the separate areas to determine the total surface area you need to cover in sod. Using the previous example, the rectangular lawn with a rounded end has a total area of 2,153.42 square feet: 1,800 + 353.42 = 2,153.42.

Divide the total square footage by 9, the number of square feet in one square yard; sod typically is sold by the square yard. Round up to the next whole square yard to determine the square yards of sod you need to create the lawn. For example, for a lawn with a total area of 2,153.42 square feet, you need 240 square yards of sod -- 2,153.42 / 9 = 239.27.

Add an extra 10 percent to the size to compensate for measuring errors and waste resulting from cutting and fitting. To conclude the example, add 24 square yards to the 240 square yards of sod to allow for errors, taking the total area to 264 square yards.