When planning to build a deck, one of the biggest challenges is figuring out how many decking boards you’ll need. Buying too few means delays, while buying too many can be costly. To make this process easier, we created the Deck Materials Calculator – a free, easy-to-use tool that instantly tells you your deck’s total square footage and how many boards you’ll need.
Deck Materials Calculator
What is the Deck Materials Calculator?
The Deck Materials Calculator is an online tool designed to help homeowners, builders, and landscapers quickly estimate deck material needs. By entering the deck’s dimensions and the size of each board, you’ll get two essential results:
- Total Deck Area (in square feet)
- Number of Decking Boards Required
This eliminates guesswork and ensures you purchase the right amount of materials before starting your project.
How to Use the Deck Materials Calculator (Step-by-Step)
Using the calculator is simple and requires just a few inputs:
- Enter the deck length (ft) – Measure the full length of your deck and type it in.
- Enter the deck width (ft) – Measure the width and input the value.
- Enter the board size (ft² per board) – Determine how much area one board covers. For example, if a board is 6 inches wide and 8 feet long, it covers 4 ft².
- Click “Calculate” – The tool will instantly show you the total deck area and the number of boards needed.
- Click “Reset” if you want to clear values and start over.
That’s it—your results appear in seconds.
Practical Example: Calculating Materials for a 12x16 Deck
Let’s walk through an example:
- Deck length: 12 ft
- Deck width: 16 ft
- Board size: Each board covers 5.5 inches × 8 ft = 3.67 ft²
Step 1: Multiply deck length × width = 192 ft² total area.
Step 2: Divide total area by board coverage: 192 ÷ 3.67 ≈ 53 boards needed.
With this calculation, you’ll know to order at least 53 boards. It’s smart to add 5–10% extra for cuts, waste, and future repairs, so ordering around 58 boards would be ideal.
Why Use a Deck Materials Calculator?
- Accuracy – Avoid over- or under-ordering.
- Time-saving – No need for complex manual math.
- Budget control – Estimate costs more precisely.
- Project planning – Helps you schedule and order supplies efficiently.
- Flexibility – Works for decks of any size, shape, or material.
Extra Tips for Deck Material Planning
- Account for spacing: Gaps between boards for drainage may slightly change material needs.
- Include stairs and railings: These require additional boards not factored into the main area.
- Factor in board orientation: Whether boards run lengthwise or widthwise can impact waste.
- Choose quality materials: Pressure-treated wood, cedar, or composite decking each have different coverage and durability.
- Order extra boards: A 5–10% buffer ensures you’re covered for mistakes, cuts, or future repairs.
FAQs About Deck Material Calculations
1. What measurements do I need to use the calculator?
You need the deck’s length, width, and the coverage area of one board in square feet.
2. How do I calculate board coverage?
Multiply a board’s width (in feet) by its length (in feet). For example, a 6-inch (0.5 ft) × 10 ft board = 5 ft².
3. Can I use this calculator for composite decking?
Yes, just enter the coverage area per composite board, and the calculator will give accurate results.
4. Should I add extra boards to my order?
Yes, it’s recommended to add 5–10% extra for waste, cutting, and future replacements.
5. Can I use this tool for irregular-shaped decks?
Yes, but break the deck into smaller rectangular sections, calculate each area, then add them together.
6. Does the calculator include railings and stairs?
No, this tool is designed for deck surface boards only. Railings, stairs, and posts must be calculated separately.
7. Can the calculator help with budget planning?
Indirectly, yes. Once you know how many boards you need, you can multiply that by the cost per board to estimate expenses.
8. Is the calculator suitable for contractors?
Absolutely. It saves time and ensures accurate estimates for clients.
9. What’s the difference between nominal and actual board sizes?
A nominal “2x6” board actually measures about 1.5" × 5.5". Always use actual dimensions to calculate coverage.
10. How do I calculate decking for diagonal patterns?
Diagonal or herringbone patterns require about 10–15% more material than straight layouts.
11. Does this tool work in metric measurements?
Currently, the calculator uses feet. You can convert metric measurements into feet before inputting.
12. Can I use this for patios or other surfaces?
Yes, any rectangular surface that requires boards can be calculated, such as patios, platforms, or stages.
13. How precise is the result?
The calculator rounds up to the nearest whole board to ensure full coverage.
14. What if I enter decimals in deck size?
The tool accepts decimal inputs, so you can enter precise measurements (e.g., 12.5 ft).
15. Does this calculator work for multi-level decks?
Yes, calculate each level separately and then add the results.
16. Can I save my results?
While the tool doesn’t save results, you can write them down or screenshot them for reference.
17. Can I use this tool on mobile devices?
Yes, the calculator is fully responsive and works on phones, tablets, and desktops.
18. What materials can this calculator be used for?
It works for wood, composite, PVC, and other decking boards.
19. How do I know if I measured correctly?
Double-check deck dimensions with a tape measure and confirm board sizes with product specifications.
20. Will this calculator help me cut costs?
Yes, by avoiding over-purchasing and planning more accurately, you’ll reduce waste and control your budget.
Final Thoughts
Building a deck is a rewarding project, but it requires precise planning to avoid costly mistakes. The Deck Materials Calculator helps you determine your deck’s total area and the exact number of boards you’ll need. With just a few inputs, you’ll have reliable results that make shopping for materials easier, faster, and more cost-effective.