The Deck Board and Framing Joist Calculator computes complete lumber takeoffs for residential deck surfaces, including framing joist counts, total surface deck boards, 10% cut-waste linear footage, and structural screw fasteners.

### Framing & Decking Formulas Material counts are derived from dimensional deck geometry and standard carpentry spacing: $$\text{Joists Count} = \left\lceil \frac{\text{Length (inches)}}{\text{Joist Spacing (inches)}} \right\rceil + 1$$ $$\text{Effective Board Width (ft)} = \frac{\text{Board Width} + 0.125}{12}$$ $$\text{Surface Boards} = \left\lceil \frac{\text{Projection Width (ft)}}{\text{Effective Board Width (ft)}} \right\rceil$$ $$\text{Total Linear Feet} = \text{Surface Boards} \times \text{Length} \times 1.10 \quad (10\% \text{ cut waste})$$ $$\text{Screws Required} = \text{Surface Boards} \times \text{Joists Count} \times 2$$

### Worked Material Takeoff Calculating lumber requirements for a 16 ft length by 12 ft projection deck with 16-inch on-center joists and standard 5.5-inch boards ($5/4 \times 6$ lumber): - **Framing Joists**: $\lceil (16 \times 12) / 16 \rceil + 1 = 13$ framing joists - **Effective Board Width**: $(5.5 + 0.125) / 12 = 0.46875\text{ ft}$ - **Deck Boards**: $\lceil 12 / 0.46875 \rceil = 26$ boards across the 12-ft width - **Total Linear Feet**: $26 \times 16 \times 1.10 = 458\text{ linear feet}$ - **Fasteners**: $26 \times 13 \times 2 = 676$ deck screws

### Local Calculation & Privacy All formulas execute client-side in your web browser. No project addresses, lumber quotes, or contractor blueprints are uploaded to any server.