Measure the length and width of the walkway, in inches.
Multiply the length and width together to calculate the total area. As an example, if you measured 144 inches by 240 inches, then you would multiply those two numbers to achieve 34,560 square inches.
If you had previously measured in feet, you can convert the area to square inches by multiplying by 144.
Add the walkway length and the width together and multiply by two to calculate the perimeter. As an example, in the example, 144 inches plus 240 inches, gives you 384 inches. Multiplying this number by 2 gives you a walkway perimeter of 768 inches.
Measure the length and width of one paver. Multiply those figures to calculate the area of a paver. As an example, a paver which measures 4 inches by 8 inches would have an area of 32 square inches.
Divide the walkway area by the paver area to calculate the number of pavers that will fit. In the example, you would divide 34,560 by 32, which tells you 1,080 pavers will fit.
Multiply this number by 1.05% to factor in a 5 percent margin of error to account for breakage or trimming. In the example, 1,080 pavers times 1.05 gives you 1,134 pavers required for the area.
Divide the walkway perimeter by the longest dimension of your paver to calculate the number of pavers needed for the edge. In the example, you would divide 768 inches by 8 inches, which tells you 96 pavers are required for the perimeter.
Add the number of pavers required for the area and perimeter to calculate total pavers required. In the example, 1,134 plus 96 results in 1,230 pavers required.