Deck Calculator
Estimate deck boards, joists, and materials for your deck project. Get accurate counts for any deck size.
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Deck Building Guide
Deck board count assumes boards run parallel to the deck length. Add 10% for waste. Use pressure-treated or composite lumber for longevity.
- Joist spacing: 16 inches on center is standard for residential decks
- Don't forget hardware: screws, brackets, and post anchors
- Consider a moisture barrier between the deck and the house
Frequently Asked Questions
How many deck boards do I need?
Divide the deck width in inches by the board width to get the number of board rows. Multiply by the number of rows needed. A 12x16 deck using 5.5-inch boards needs approximately 42 deck boards.
What is the best wood for a deck?
Pressure-treated pine is the most affordable and durable option. Cedar and redwood are naturally rot-resistant and look beautiful. Composite decking costs more but requires no maintenance.
How far apart should deck joists be?
Standard joist spacing is 16 inches on center for residential decks. Use 12-inch spacing for heavy-duty decks or when using composite decking. 24-inch spacing is for light-duty decks.
Do I need a permit to build a deck?
Most municipalities require a building permit for decks over 30 inches above ground. Check with your local building department before starting construction.