Decking Calculator — How Many Deck Boards Do I Need?
Estimate the number of deck boards needed for any deck area with board width and waste factor.
Your Results
39
Boards Needed
35
Without Waste
468
Linear Feet
5.50
sq ft / board
Board Count at Different Waste Factors
| Waste | Base Boards | Total Boards | Linear Feet |
|---|---|---|---|
| 0% waste | 35 | 35 | 420 |
| 5% waste | 35 | 37 | 444 |
| 10% waste | 35 | 39 | 468 |
| 15% waste | 35 | 41 | 492 |
Formula
Formula: Boards = ceil(Deck Area ÷ (Board Width÷12 × Board Length)) × (1 + Waste%)
Worked Example
Example: 20×14 ft deck (280 sq ft), 2×6 boards, 12 ft length, 10% waste.
Coverage/board = 5.5 sq ft; Base = ceil(280÷5.5) = 51; With waste = 57 boards; Linear feet = 684
Frequently Asked Questions
How many deck boards for a 12×16 ft deck?
192 sq ft using 2×6 boards (5.5 in wide, 12 ft long): each covers 5.5 sq ft. Need ceil(192÷5.5) = 35 boards + 10% waste = 39 boards.
Should I use 12 ft or 16 ft deck boards?
Match board length to deck's shorter dimension to minimize cuts. 12 ft boards for 12 ft wide deck; 16 ft boards for 16 ft wide deck.
What is the actual width of a 2×6?
A nominal 2×6 is 1.5 in × 5.5 in actual. Always use actual dimensions (5.5 in for 2×6) in calculations.
How much waste factor for decking?
Simple rectangle: 5–8%. Angled or diagonal: 10–15%.
How do I calculate linear feet of decking?
Linear feet = number of boards × board length. For 39 boards at 12 ft = 468 linear feet.