To calculate the approximate number of decking boards required we take the area of each board (150mm width x 2200mm length) which works out to 0.33sqm per board.
Measure the length times the width of your proposed decking area and divide by 0.33.
For example: for a decking area measuring 4m x 5m the total area is 20 m2, if we divide this by 0.33 we get approx. 61 boards. As a general rule, we add 10% for cuts and mistakes, which would take this board total to around 67 decking boards.