Use this calculator to estimate the linear feet of lumber needed for framing your shed, including walls and a basic gable roof structure. This tool helps you plan your material purchases more accurately.
Understanding Your Shed Lumber Needs
Building a shed is a rewarding project, but accurately estimating the lumber required can be a challenge. Our Shed Lumber Calculator simplifies this process by providing an estimate of the linear feet of various lumber components for your shed's framing.
How the Calculator Works
This calculator takes into account the basic dimensions of your shed and common framing practices to provide a comprehensive estimate. Here's a breakdown of the inputs:
Shed Length & Width: These define the footprint of your shed.
Wall Height: The vertical height of your shed walls, typically from the bottom plate to the top plate.
Stud Spacing: The distance between the centers of your wall studs and roof rafters. Common spacings are 16 inches or 24 inches on center.
Roof Pitch Rise: For a gable roof, this is the "rise" component of your roof's slope (e.g., a 4/12 pitch means 4 inches of rise for every 12 inches of run). A higher number indicates a steeper roof.
Roof Overhang: The distance your roof extends beyond the wall framing, providing protection from rain and sun. This applies to both the eaves (along the long sides) and the rakes (along the gable ends).
Number of Doors & Windows: These openings require additional framing (headers, jack studs, cripple studs) which the calculator accounts for.
What the Results Mean
The calculator provides estimates in linear feet for the following components:
Wall Studs: The vertical framing members of your walls.
Wall Plates: The horizontal lumber at the top (double top plate) and bottom (single bottom plate) of your walls.
Roof Rafters: The sloping members that form the roof structure.
Ridge Board: The horizontal board at the peak of your gable roof where the rafters meet.
Fascia Boards: The boards that cover the ends of the rafters along the eaves and rakes, providing a finished edge and supporting gutters.
Important Considerations
Waste Factor: Always add a waste factor (typically 10-15%) to your total lumber estimate. Cuts, mistakes, and damaged pieces are inevitable.
Lumber Dimensions: This calculator provides linear feet. You'll need to decide on the specific dimensions of lumber (e.g., 2×4, 2×6) based on your shed's design and local building codes.
Local Building Codes: Always check your local building codes for specific requirements regarding stud spacing, lumber dimensions, and hurricane/seismic bracing.
Additional Framing: This calculator provides a basic estimate. Complex shed designs, multiple stories, or specific structural requirements may need more detailed planning.
Sheathing & Siding: This calculator is for framing lumber only. It does not include estimates for plywood sheathing, siding, roofing materials, or trim.
Example Usage:
Let's say you're building an 8×10 shed with 8-foot walls, 16-inch stud spacing, a 4/12 roof pitch, and a 0.5-foot overhang. You plan for one door and one window. Input these values into the calculator, and it will provide an estimate of the linear feet for each lumber category, helping you create your shopping list.
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function calculateLumber() {
var shedLength = parseFloat(document.getElementById('shedLength').value);
var shedWidth = parseFloat(document.getElementById('shedWidth').value);
var wallHeight = parseFloat(document.getElementById('wallHeight').value);
var studSpacing = parseFloat(document.getElementById('studSpacing').value);
var roofPitchRise = parseFloat(document.getElementById('roofPitchRise').value);
var roofOverhang = parseFloat(document.getElementById('roofOverhang').value);
var numDoors = parseInt(document.getElementById('numDoors').value);
var numWindows = parseInt(document.getElementById('numWindows').value);
var resultDiv = document.getElementById('lumberResult');
resultDiv.innerHTML = "; // Clear previous results
// Input validation
if (isNaN(shedLength) || shedLength <= 0 ||
isNaN(shedWidth) || shedWidth <= 0 ||
isNaN(wallHeight) || wallHeight <= 0 ||
isNaN(studSpacing) || studSpacing <= 0 ||
isNaN(roofPitchRise) || roofPitchRise < 0 ||
isNaN(roofOverhang) || roofOverhang < 0 ||
isNaN(numDoors) || numDoors < 0 ||
isNaN(numWindows) || numWindows < 0) {
resultDiv.innerHTML = 'Please enter valid positive numbers for all fields.';
return;
}
// — Wall Framing Calculations —
var perimeter = 2 * (shedLength + shedWidth);
// Calculate studs for each wall length, then sum and adjust for corners
var numWallStudsLongWall = Math.ceil((shedLength * 12) / studSpacing) + 1;
var numWallStudsShortWall = Math.ceil((shedWidth * 12) / studSpacing) + 1;
// Total base studs (accounting for shared corner studs)
var totalBaseStuds = (numWallStudsLongWall * 2) + (numWallStudsShortWall * 2) – 4;
// Extra studs for openings (e.g., king, jack, cripples, headers)
// Common rule of thumb: 3 extra studs per door, 2 per window
var extraStudsForOpenings = (numDoors * 3) + (numWindows * 2);
var totalStuds = totalBaseStuds + extraStudsForOpenings;
var linearFeetStuds = totalStuds * wallHeight;
// Plates: one bottom plate, two top plates
var linearFeetPlates = perimeter * 3;
// — Roof Framing Calculations (Gable Roof) —
var roofPitchRun = 12; // Standard run for pitch ratio (e.g., 4/12)
var halfShedWidth = shedWidth / 2;
var roofRise = (roofPitchRise / roofPitchRun) * halfShedWidth;
// Rafter length using Pythagorean theorem
var rafterLength = Math.sqrt(Math.pow(halfShedWidth, 2) + Math.pow(roofRise, 2));
// Number of rafters per side (similar spacing to studs)
var numRaftersPerSide = Math.ceil((shedLength * 12) / studSpacing) + 1;
var totalRafters = numRaftersPerSide * 2; // For both sides of the gable roof
var linearFeetRafters = totalRafters * rafterLength;
// Ridge board length
var linearFeetRidgeBoard = shedLength;
// Fascia boards: along the eaves and the rakes
var eaveLength = shedLength + (roofOverhang * 2); // Eaves extend past walls
var rakeLength = rafterLength + roofOverhang; // Rakes extend past rafters
var linearFeetFascia = (eaveLength * 2) + (rakeLength * 2); // Two eaves, two rakes
// — Total Linear Feet —
var totalLinearFeet = linearFeetStuds + linearFeetPlates + linearFeetRafters + linearFeetRidgeBoard + linearFeetFascia;
// Display results
var resultsHtml = '
Estimated Lumber Requirements:
';
resultsHtml += 'Wall Studs: ' + linearFeetStuds.toFixed(2) + ' linear feet';
resultsHtml += 'Wall Plates (Top & Bottom): ' + linearFeetPlates.toFixed(2) + ' linear feet';
resultsHtml += 'Roof Rafters: ' + linearFeetRafters.toFixed(2) + ' linear feet';
resultsHtml += 'Ridge Board: ' + linearFeetRidgeBoard.toFixed(2) + ' linear feet';
resultsHtml += 'Fascia Boards: ' + linearFeetFascia.toFixed(2) + ' linear feet';
resultsHtml += '—';
resultsHtml += 'Total Estimated Framing Lumber: ' + totalLinearFeet.toFixed(2) + ' linear feet';
resultsHtml += 'Remember to add a waste factor (e.g., 10-15%) to this total.';
resultDiv.innerHTML = resultsHtml;
}