The variety of grass seed available in the farming and agriculture industry is vast and determining the quality of seed is essential to calculating the amount of seed per acre. Germination tests are conducted and displayed on all the seed sold in the agricultural markets and provide the basic formula to begin calculating the amount of seed you will need. A simple mathematical formula can help anyone determine the amount of grass seed needed to plant on any amount of acreage. Species of seed must also be considered prior to planting to ensure the continuation of native grass growth. Locate the PLS (pure live seed) table on the label of the seed bag. All germination percentages and rate of purity must be displayed on the seed bag label. Determine if the species of grass seed is large or small and how many seeds you want per linear foot. A linear foot is a straight line, or row, that is one foot in length. Typically 20 seeds of a large variety and 30 for smaller species are needed per linear foot. Multiply the number of linear feet in your acreage by the total number of seeds you chose per linear foot. 1 acre is approximately 209 feet by 209 feet. This will give you the exact number of seeds per acre. Divide the exact number of seeds needed to seed one acre by the number of seeds per pound for the species that you chose. Seed per pound can vary from a hundred thousand to over 1 million, depending on the species, and is usually posted on the label. Divide your amount of seeds per acre (in pounds) by the PLS percentage posted on the label of the grass seed. This will adjust the seeding rate for the quality of the PLS and determine the weight in pounds of seed needed to seed one acre effectively.