Find how many deck boards your deck needs. Each dimension has its own unit selector (in/ft/yd/m).
Decking is estimated by area. Measure each part of the deck (any unit) and add them up. One board covers its length times its actual width - a nominal 6-inch board is really 5.5 inches, so use the preset. Divide the deck area by one board's coverage and add about 10% for waste. Joists, posts and fasteners are separate.
Use the deck calculator to estimate deck surface area, board count, linear feet and material cost. It is intended for the decking surface, not the full structural frame.
Start with the calculator that matches how your material is sold: area, length, volume, count, weight or electrical load. Enter one work area at a time, use the unit selector beside each measurement, then review the order quantity and cost fields before comparing supplier quotes.
Most calculators can save the current estimate in your browser, reload named estimates, print a copy, switch to dark mode or create a shareable link. Those tools are intended for planning and communication; always confirm final quantities, coverage rates, density, code requirements and pricing with the supplier or contractor responsible for the work.