Donaldson R F Fence & Deck Calculator
Work out how many posts, panels, boards, joists and screws you need for a fence or a deck before you go shopping.
How the estimates are made
Fence: gates are subtracted from the length; the rest is divided into sections at the post spacing (rounded up), and posts = sections + 1, plus one extra post for each gate. Ready-made panels need one per section; for pickets, each section needs enough boards to fill the post spacing at the chosen width and gap, plus the rails. Corners share posts, so they do not add any. Deck: the number of board rows is the width divided by board width plus gap; the boards you buy are the total board length (rows × deck length) plus waste, divided by the length you can get. Joists run across the boards at the spacing you choose (400 mm / 16 in is common for standard decking); every board is fixed with two screws at each joist. Footings are estimated at a maximum spacing of 1.8 m (6 ft) in both directions. Span limits, timber sizes, frost depth and permit rules depend on your location — check local building codes and the timber supplier's span tables before you build.