Lumber Calculator - Calculate Board Feet & Lumber Cost

<h2>Lumber Calculator - Calculate Lumber Needs</h2> <p>Calculate lumber requirements instantly with our free calculator. Get accurate estimates for framing, decking, fencing, and other projects using board feet and linear foot calculations.</p> <h2>Calculate Your Lumber Needs</h2> <p><strong>Project Type:</strong></p> <ul> <li>Framing</li> <li>Decking</li> <li>Fencing</li> <li>Siding</li> <li>General</li> </ul> <p>[Select Project Type]</p> <p><strong>Lumber Details:</strong></p> <ul> <li>Board Length: [Input] feet</li> <li>Board Width: [Input] inches</li> <li>Board Thickness: [Input] inches</li> <li>Quantity: [Input] boards</li> </ul> <p>[Calculate Button]</p> <p><strong>Your Results:</strong></p> <ul> <li><strong>Linear Feet:</strong> [Amount] linear feet</li> <li><strong>Board Feet:</strong> [Amount] board feet</li> <li><strong>Square Footage:</strong> [Amount] square feet (if applicable)</li> <li><strong>Cubic Feet:</strong> [Amount] cubic feet</li> </ul> <p><strong>Cost Estimate:</strong></p> <ul> <li><strong>Price per Board Foot:</strong> $[Input] (optional)</li> <li><strong>Total Cost:</strong> $[Amount]</li> </ul> <hr> <h2>What is Lumber?</h2> <p><strong>Lumber</strong> is wood that has been processed into beams and planks, a stage in the process of wood production. Lumber is mainly used for structural purposes but has many other applications as well.</p> <h3>Lumber Dimensions</h3> <p><strong>Nominal vs. Actual Sizes:</strong></p> <table> <thead> <tr> <th>Nominal</th> <th>Actual (Thickness)</th> <th>Actual (Width)</th> </tr> </thead> <tbody><tr> <td>1 × 4</td> <td>3/4&quot;</td> <td>3-1/2&quot;</td> </tr> <tr> <td>1 × 6</td> <td>3/4&quot;</td> <td>5-1/2&quot;</td> </tr> <tr> <td>1 × 8</td> <td>3/4&quot;</td> <td>7-1/4&quot;</td> </tr> <tr> <td>1 × 10</td> <td>3/4&quot;</td> <td>9-1/4&quot;</td> </tr> <tr> <td>1 × 12</td> <td>3/4&quot;</td> <td>11-1/4&quot;</td> </tr> <tr> <td>2 × 4</td> <td>1-1/2&quot;</td> <td>3-1/2&quot;</td> </tr> <tr> <td>2 × 6</td> <td>1-1/2&quot;</td> <td>5-1/2&quot;</td> </tr> <tr> <td>2 × 8</td> <td>1-1/2&quot;</td> <td>7-1/4&quot;</td> </tr> <tr> <td>2 × 10</td> <td>1-1/2&quot;</td> <td>9-1/4&quot;</td> </tr> <tr> <td>2 × 12</td> <td>1-1/2&quot;</td> <td>11-1/4&quot;</td> </tr> </tbody></table> <p><strong>Note:</strong> Nominal size is what it&#39;s called. Actual size is what it measures after drying and surfacing.</p> <h3>Types of Lumber</h3> <p><strong>Dimensional Lumber:</strong></p> <ul> <li>2×4, 2×6, 2×8, etc.</li> <li>Used for framing</li> <li>Softwood species (pine, spruce, fir)</li> </ul> <p><strong>Board Lumber:</strong></p> <ul> <li>1×4, 1×6, 1×8, etc.</li> <li>Used for shelving, trim, fencing</li> <li>Softer and thinner</li> </ul> <p><strong>Engineered Lumber:</strong></p> <ul> <li>LVL (Laminated Veneer Lumber)</li> <li>LSL (Laminated Strand Lumber)</li> <li>PSL (Parallel Strand Lumber)</li> <li>Stronger, straighter, more expensive</li> </ul> <h3>Why Lumber Calculations Matter</h3> <ol> <li><strong>Budget Accuracy</strong>: Avoid costly overruns</li> <li><strong>Material Efficiency</strong>: Minimize waste</li> <li><strong>Project Planning</strong>: Ensure adequate supply</li> <li><strong>Cost Comparison</strong>: Compare lumber types and suppliers</li> <li><strong>Transportation</strong>: Know load size for delivery</li> </ol> <h2>Lumber Measurements</h2> <h3>Board Foot Calculation</h3> <p><strong>What is a Board Foot?</strong></p> <ul> <li>A board foot is 144 cubic inches of wood</li> <li>12&quot; × 12&quot; × 1&quot; = 1 board foot</li> <li>Standard unit for measuring lumber volume</li> </ul> <p><strong>Formula:</strong></p> <pre><code>Board Feet = (Thickness × Width × Length) ÷ 12 </code></pre> <p>(Thickness and width in inches, length in feet)</p> <p><strong>Example:</strong></p> <pre><code>2 × 4 × 8 feet Board Feet = (2 × 4 × 8) ÷ 12 Board Feet = 64 ÷ 12 = 5.33 board feet </code></pre> <h3>Linear Foot Calculation</h3> <p><strong>What is a Linear Foot?</strong></p> <ul> <li>Measurement of length only</li> <li>Doesn&#39;t account for thickness or width</li> <li>Used for pricing some lumber</li> </ul> <p><strong>Formula:</strong></p> <pre><code>Linear Feet = Length × Quantity </code></pre> <p><strong>Example:</strong></p> <pre><code>10 boards, each 8 feet long Linear Feet = 10 × 8 = 80 linear feet </code></pre> <h3>Square Foot Coverage</h3> <p><strong>For Decking and Siding:</strong></p> <p><strong>Formula:</strong></p> <pre><code>Square Footage = (Width × Length) ÷ 144 × Quantity </code></pre> <p>(Width and length in inches)</p> <p><strong>Example (1 × 6 × 8&#39; decking):</strong></p> <pre><code>Actual width: 5-1/2&quot; = 5.5 inches Length: 8 feet = 96 inches

Coverage per board = 5.5 × 96 = 528 sq inches Convert to sq feet: 528 ÷ 144 = 3.67 sq ft

For 100 boards: 100 × 3.67 = 367 sq ft coverage </code></pre> <h2>Framing Calculator</h2> <h3>Wall Framing</h3> <p><strong>Studs:</strong></p> <ul> <li>Spacing: 16 inches on center (standard)</li> <li>Formula: (Wall length ÷ 1.33) + 1 for corners</li> </ul> <p><strong>Top and Bottom Plates:</strong></p> <ul> <li>2 plates (double top plate common)</li> <li>Length: Wall length × 2</li> </ul> <p><strong>Example (8&#39; × 10&#39; wall):</strong></p> <pre><code>Studs: (10 ÷ 1.33) + 1 = 8.5 = 9 studs Add corners: +4 studs = 13 studs Add openings: Varies

Top and Bottom Plates: 10&#39; × 2 = 20&#39; (for single top plate) 10&#39; × 3 = 30&#39; (for double top plate) </code></pre> <h3>Floor Framing (Joists)</h3> <p><strong>Joist Spacing:</strong></p> <ul> <li>12&quot; on center: Heavy loads, long spans</li> <li>16&quot; on center: Standard residential</li> <li>24&quot; on center: Lighter loads, shorter spans</li> </ul> <p><strong>Formula:</strong></p> <pre><code>Number of Joists = (Length ÷ Spacing in feet) + 1 </code></pre> <p><strong>Example (20&#39; span, 16&quot; spacing):</strong></p> <pre><code>16&quot; = 1.33 feet Number of joists = (20 ÷ 1.33) + 1 = 16.04 = 17 joists

Add rim joists: +2 Total: 19 joists </code></pre> <h3>Roof Framing (Rafters)</h3> <p><strong>Rafter Spacing:</strong></p> <ul> <li>Typically 16&quot; or 24&quot; on center</li> <li>Depends on roof load and rafter size</li> </ul> <p><strong>Formula:</strong></p> <pre><code>Number of Rafters = (Building width ÷ Spacing) × 2 </code></pre> <p><strong>Example (24&#39; wide building, 24&quot; spacing):</strong></p> <pre><code>24&quot; = 2 feet Rafters per side = (24 ÷ 2) + 1 = 13 Total rafters = 13 × 2 = 26 rafters </code></pre> <h2>Decking Calculator</h2> <h3>Deck Boards</h3> <p><strong>Calculate Board Quantity:</strong></p> <p><strong>Formula:</strong></p> <pre><code>Deck Width ÷ Board Width (including gap) = Number of Boards Deck Length ÷ Board Length = Rows Needed </code></pre> <p><strong>Example (12&#39; × 16&#39; deck with 5-1/2&quot; wide boards):</strong></p> <pre><code>Deck width: 12&#39; = 144&quot; Board width: 5-1/2&quot; = 5.5&quot; Gap: 1/4&quot; = 0.25&quot; Total width per board: 5.75&quot;

Number of boards = 144 ÷ 5.75 = 25.04 = 26 boards Length: 16 feet Total linear feet = 26 × 16 = 416 linear feet

If using 16&#39; boards: 416 ÷ 16 = 26 boards Add 10% waste: 26 × 1.10 = 28.6 = 29 boards </code></pre> <h3>Joists and Beams</h3> <p><strong>Joist Spacing:</strong></p> <ul> <li>12&quot; on center for diagonal decking</li> <li>16&quot; on center for standard decking</li> <li>24&quot; on center for heavy decking</li> </ul> <p><strong>Beam Spans:</strong></p> <ul> <li>Depends on joist size and spacing</li> <li>Consult span tables for your situation</li> </ul> <h3>Example Deck Material List</h3> <p><strong>12&#39; × 16&#39; deck:</strong></p> <p><strong>Joists (2 × 8, 16&quot; spacing):</strong></p> <pre><code>Spacing: 16&quot; = 1.33&#39; Number: (12&#39; ÷ 1.33) + 1 = 10 joists Length: 16 feet each Total: 10 × 16&#39; = 160 linear feet of 2 × 8 </code></pre> <p><strong>Beams (2 × 10 or 2 × 12):</strong></p> <pre><code>Three beams supporting joists Length: 12 feet each Total: 3 × 12&#39; = 36 linear feet </code></pre> <p><strong>Posts (4 × 4):</strong></p> <pre><code>4 corners + potentially more Height: 8 feet each Total: 4 × 8&#39; = 32 linear feet </code></pre> <p><strong>Decking (1 × 6 or 5/4 × 6):</strong></p> <pre><code>26 boards (calculated above) Length: 16 feet each Total: 26 × 16&#39; = 416 linear feet </code></pre> <h2>Fencing Calculator</h2> <h3>Privacy Fence (6&#39; tall)</h3> <p><strong>Posts (4 × 4):</strong></p> <ul> <li>Spacing: 8 feet on center</li> <li>Height: 8 feet (2 feet in ground)</li> </ul> <p><strong>Formula:</strong></p> <pre><code>Number of Posts = (Fence Length ÷ 8) + 1 </code></pre> <p><strong>Example (100 linear feet):</strong></p> <pre><code>Posts: (100 ÷ 8) + 1 = 13.5 = 14 posts Length per post: 8 feet Total: 14 × 8&#39; = 112 linear feet of 4 × 4 </code></pre> <p><strong>Rails (2 × 4):</strong></p> <ul> <li>Two rails per section (top and bottom)</li> <li>Spacing: 8 feet between posts</li> </ul> <p><strong>Formula:</strong></p> <pre><code>Number of Rails = (Fence Length ÷ 8) × 2 </code></pre> <p><strong>Example:</strong></p> <pre><code>Rails: (100 ÷ 8) × 2 = 25 rails Length: 8 feet each Total: 25 × 8&#39; = 200 linear feet of 2 × 4 </code></pre> <p><strong>Pickets (1 × 6 or 1 × 4):</strong></p> <ul> <li>Width: 5-1/2&quot; for 1 × 6</li> <li>Spacing: Usually 1/4&quot; to 1/2&quot; gap</li> </ul> <p><strong>Formula:</strong></p> <pre><code>Pickets per Section = (96&quot; ÷ (Picket Width + Gap)) Number of Sections = Fence Length ÷ 8 Total Pickets = Pickets per Section × Number of Sections </code></pre> <p><strong>Example (1 × 6 pickets with 1/4&quot; gap):</strong></p> <pre><code>Picket width: 5.5&quot; Gap: 0.25&quot; Total: 5.75&quot;

Pickets per 8&#39; section: 96 ÷ 5.75 = 16.7 = 17 pickets Sections: 100 ÷ 8 = 12.5 = 13 sections Total pickets: 17 × 13 = 221 pickets </code></pre> <h2>Board Foot vs. Linear Foot Pricing</h2> <h3>Understanding the Difference</h3> <p><strong>Linear Foot Pricing:</strong></p> <ul> <li>Price per foot of length</li> <li>Common for: Siding, fencing, trim</li> <li>Same price regardless of dimensions</li> </ul> <p><strong>Board Foot Pricing:</strong></p> <ul> <li>Price per 144 cubic inches</li> <li>Common for: Dimensional lumber, hardwood</li> <li>Accounts for thickness, width, and length</li> </ul> <p><strong>Example Comparison:</strong></p> <p><strong>2 × 4 × 8&#39; at $0.65 per linear foot:</strong></p> <pre><code>Cost: 8 × $0.65 = $5.20 per board Board feet: 5.33 BF Cost per BF: $5.20 ÷ 5.33 = $0.98 per BF </code></pre> <p><strong>2 × 6 × 8&#39; at $0.85 per linear foot:</strong></p> <pre><code>Cost: 8 × $0.85 = $6.80 per board Board feet: 8 BF Cost per BF: $6.80 ÷ 8 = $0.85 per BF </code></pre> <p><strong>2 × 6 is cheaper per board foot!</strong></p> <h2>Cost Estimation</h2> <h3>Lumber Cost Factors</h3> <p><strong>Material Cost Variables:</strong></p> <ul> <li>Lumber grade (#1, #2, Premium)</li> <li>Species (pine, cedar, redwood, composite)</li> <li>Treatment (pressure-treated, untreated)</li> <li>Supply and demand</li> <li>Geographic location</li> </ul> <p><strong>Current Prices (2024 averages):</strong></p> <table> <thead> <tr> <th>Lumber Type</th> <th>Price per Linear Foot</th> <th>Price per Board Foot</th> </tr> </thead> <tbody><tr> <td><strong>2 × 4 × 8&#39; SPF</strong></td> <td>$0.65 - $0.85</td> <td>$0.98 - $1.28</td> </tr> <tr> <td><strong>2 × 6 × 8&#39; SPF</strong></td> <td>$0.85 - $1.15</td> <td>$0.85 - $1.15</td> </tr> <tr> <td><strong>2 × 8 × 8&#39; SPF</strong></td> <td>$1.15 - $1.55</td> <td>$0.86 - $1.16</td> </tr> <tr> <td><strong>4 × 4 × 8&#39; PT</strong></td> <td>$2.50 - $3.50</td> <td>$2.08 - $2.92</td> </tr> <tr> <td><strong>1 × 6 Cedar</strong></td> <td>$1.75 - $2.50</td> <td>$2.67 - $3.82</td> </tr> <tr> <td><strong>5/4 × 6 Decking</strong></td> <td>$2.50 - $4.00</td> <td>$2.08 - $3.33</td> </tr> </tbody></table> <h3>Complete Project Cost Example</h3> <p><strong>12&#39; × 16&#39; Deck:</strong></p> <p><strong>Lumber:</strong></p> <ul> <li>Joists (2 × 8): 160&#39; × $1.25 = $200</li> <li>Beams (2 × 10): 36&#39; × $1.50 = $54</li> <li>Posts (4 × 4 PT): 32&#39; × $3.00 = $96</li> <li>Decking (5/4 × 6): 416&#39; × $3.00 = $1,248</li> <li><strong>Lumber Total: $1,598</strong></li> </ul> <p><strong>Hardware:</strong></p> <ul> <li>Joist hangers: 40 × $5 = $200</li> <li>Post bases: 4 × $15 = $60</li> <li>Screws/fasteners: $150</li> <li><strong>Hardware Total: $410</strong></li> </ul> <p><strong>Other Materials:</strong></p> <ul> <li>Concrete for footings: $100</li> <li>Railing system: $400</li> <li>Stairs: $250</li> <li><strong>Other Total: $750</strong></li> </ul> <p><strong>Grand Total:</strong></p> <ul> <li>Materials only: $1,598 + $410 + $750 = $2,758</li> <li>With labor ($15/sq ft): $2,758 + $2,880 = $5,638</li> </ul> <h2>Lumber Grades</h2> <h3>Softwood Grading</h3> <p><strong>Construction Grade:</strong></p> <ul> <li>#2: Standard construction grade, most common</li> <li>#1: Better appearance, fewer knots</li> <li>Premium: Best appearance, clear lumber</li> </ul> <p><strong>Uses:</strong></p> <ul> <li>Studs: #2 grade is typical</li> <li>visible areas: #1 or Premium</li> <li>Structural: #2 is acceptable</li> </ul> <h3>Hardwood Grading</h3> <p><strong>FAS (First and Second):</strong></p> <ul> <li>Highest grade</li> <li>83% clear face</li> <li>Expensive</li> <li>Best for: Fine furniture, cabinets</li> </ul> <p><strong>Select:</strong></p> <ul> <li>Slightly lower than FAS</li> <li>Good for: Most projects</li> </ul> <p><strong>#1 Common:</strong></p> <ul> <li>More defects</li> <li>Lower cost</li> <li>Best for: Painted projects, shelving</li> </ul> <h2>Waste Factors</h2> <h3>How Much Extra to Buy</h3> <p><strong>Standard Projects:</strong></p> <ul> <li>Framing: 5-10%</li> <li>Decking: 10-15%</li> <li>Fencing: 10%</li> <li>Siding: 10%</li> </ul> <p><strong>Increase When:</strong></p> <ul> <li>Inexperienced builder</li> <li>Complex cuts required</li> <li>Lower grade lumber (more defects)</li> <li>Hard-to-find species (can&#39;t easily get more)</li> </ul> <p><strong>Example:</strong></p> <pre><code>Calculated need: 1,000 board feet Project: Decking (add 15%) 1,000 × 1.15 = 1,150 board feet Order: 1,150 BF </code></pre> <h2>Common Mistakes</h2> <h3>Mistake 1: Nominal vs. Actual</h3> <p><strong>Problem:</strong> Using nominal dimensions for calculations</p> <p><strong>Solution:</strong> Always use actual dimensions for coverage calculations</p> <h3>Mistake 2: Forgetting Waste</h3> <p><strong>Problem:</strong> Ordering exact calculated amount</p> <p><strong>Solution:</strong> Always add 5-15% for waste, defects, and mistakes</p> <h3>Mistake 3: Wrong Spacing</h3> <p><strong>Problem:</strong> Incorrect joist/stud spacing</p> <p><strong>Solution:</strong> Know your required spacing (12&quot;, 16&quot;, or 24&quot; on center)</p> <h3>Mistake 4: Ignoring Defects</h3> <p><strong>Problem:</strong> Not accounting for warped or damaged boards</p> <p><strong>Solution:</strong> Buy 5-10% extra to allow for culling bad boards</p> <h3>Mistake 5: Board Foot Confusion</h3> <p><strong>Problem:</strong> Thinking board foot equals linear foot</p> <p><strong>Solution:</strong> Remember: Board foot = volume (144 cubic inches). Linear foot = length only.</p> <h3>How do I calculate board feet?</h3> <p>Board Feet = (Thickness × Width × Length) ÷ 12. Example: 2 × 4 × 8&#39; board. (2 × 4 × 8) ÷ 12 = 5.33 board feet.</p> <h3>What&#39;s the difference between board foot and linear foot?</h3> <p>Board foot measures volume (thickness × width × length). Linear foot measures only length. Board foot pricing accounts for dimensions; linear foot is same price regardless of dimensions.</p> <h3>How many 2 × 4 studs do I need for a wall?</h3> <p>For a 10-foot wall with 16&quot; spacing: (10 ÷ 1.33) + 1 = 8.5 studs. Add 4 for corners = 13 studs. Add extra for doors/windows and cripple studs.</p> <h3>How much lumber do I need for a 12 × 16 deck?</h3> <p>Decking: ~416 linear feet of 5/4 × 6. Joists: ~160 linear feet of 2 × 8. Beams: ~36 linear feet of 2 × 10. Posts: ~32 linear feet of 4 × 4. Add 10-15% waste.</p> <h3>Why is a 2 × 4 actually 1.5 × 3.5?</h3> <p>Nominal size refers to rough cut dimensions before drying and surfacing. Planing and drying shrink the board to the actual size.</p> <h3>How do I calculate linear feet?</h3> <p>Multiply the number of boards by the length of each board. Example: 50 boards, each 8 feet long = 50 × 8 = 400 linear feet.</p> <h3>How much extra lumber should I buy?</h3> <p>Add 5-10% for framing, 10-15% for decking/fencing. More if inexperienced, using lower-grade lumber, or complex cuts are needed.</p> <h3>What does &quot;on center&quot; mean?</h3> <p>On center (OC) refers to the spacing from the center of one board to the center of the next. 16&quot; OC means 16&quot; between stud/joist centers.</p> <hr> <h2>Practice Examples</h2> <h3>Example 1: Calculate Board Feet</h3> <p><strong>Lumber:</strong></p> <ul> <li>2 × 6</li> <li>Length: 10 feet</li> <li>Quantity: 25 boards</li> </ul> <p><strong>Calculation:</strong></p> <pre><code>Board feet per board = (2 × 6 × 10) ÷ 12 = 10 BF Total board feet = 25 × 10 = 250 BF </code></pre> <h3>Example 2: Wall Framing</h3> <p><strong>Wall:</strong></p> <ul> <li>Length: 20 feet</li> <li>Height: 8 feet</li> <li>Stud spacing: 16&quot; OC</li> </ul> <p><strong>Calculation:</strong></p> <pre><code>Studs: (20 ÷ 1.33) + 1 = 16 studs Add corners: +4 = 20 studs Add for opening: +4 = 24 studs

Plates: 20&#39; × 3 = 60 linear feet of 2 × 4 </code></pre> <hr> <h2>Related Calculators</h2> <ul> <li><a href="./decking-calculator.md">Decking Calculator</a></li> <li><a href="./fencing-calculator.md">Fencing Calculator</a></li> <li><a href="./concrete-calculator.md">Concrete Calculator</a></li> <li><a href="./roofing-calculator.md">Roofing Calculator</a></li> <li><a href="./flooring-calculator.md">Flooring Calculator</a></li> </ul> <hr> <p><strong>Need Help?</strong> Our lumber calculator is perfect for contractors, DIYers, and homeowners. Calculate your lumber needs now!</p>