Calculators
Deck Calculator
Estimate deck boards and bundles to buy from deck size, board size, gap, and waste allowance locally in your browser.
Enter the deck size and a single deck board size in feet to estimate how many boards to buy, including the gap between boards and a waste allowance for cuts, breakage, and uneven edges. The calculation runs locally in your browser; your values are not uploaded or stored.
Enter board dimensions in the same unit as the deck; for example, a 5.5 inch board is about 0.46 ft. Use a small gap for drainage and expansion or 0 for touching boards. This estimate covers one rectangle and ignores posts, stairs, railings, framing, and board-length joints, so measure each section separately. Check your supplier because board sizes and bundle counts vary by product. This deck estimate is a planning guide, not a purchase guarantee.
Find how many deck boards to buy without uploading anything.
Enter the deck length and width plus a single deck board length and width, the gap between boards, an optional boards-per-bundle count, and a waste allowance to see the deck area, board count, and rounded-up bundle count. Everything runs locally in your browser, so your values are not uploaded or stored.
Frequently Asked Questions
Everything you need to know about this tool, how it works, and privacy.
What does the deck calculator show?
Enter the deck length and width, a single deck board length and width in the same unit, the gap between boards, an optional boards-per-bundle count, and a waste allowance. The calculator returns the deck area, the board coverage including the gap, and the board count with waste rounded up, plus the bundle count when boards per bundle is given, with the calculation shown. For example, a 16 by 12 ft deck with 16 by 0.46 ft boards, no gap, and 10% waste needs about 29 boards.
Which formula does the deck calculator use?
It uses deck area = deck length x deck width, board coverage = board length x (board width + gap), then boards = deck area / board coverage x (1 + waste percent / 100) rounded up, and bundles = boards / boards per bundle rounded up. Use the same length unit for the deck and the board; for example, a 5.5 inch board is about 0.46 ft. Use a small gap for drainage and expansion or 0 for touching boards.
Which inputs are accepted?
Enter a deck length, deck width, board length, and board width greater than zero through 1000000000, a gap from 0 to 1000000000 (blank means 0), an optional boards-per-bundle whole number from 1 to 1000000000, and a waste allowance from 0 to 100 percent (blank means 10). Decimal sizes are accepted. Zero sizes, negative numbers, non-numeric text, and values outside these limits show a clear error instead of a result.
Do my numbers stay private?
Yes. The calculation and copy action run locally in your browser. CodeASystem does not upload or store the values you enter.