Pergola or Shade Structure Material Calculator
ANA›Life Services Authority›National Calculator Authority›Pergola or Shade Structure Material Calculator
.calc-container { max-width: 640px; margin: 2rem 0; padding: 1.5rem; background: #fff; border: 1px solid #ddd; border-radius: 8px; box-shadow: 0 1px 3px rgba(0,0,0,0.06); font-family: system-ui, -apple-system, sans-serif; } .calc-container h3 { font-family: Georgia, serif; font-size: 1.15rem; color: #1a1a1a; margin-bottom: 1rem; padding-bottom: 0.5rem; border-bottom: 2px solid var(--ac, #3d5a80); } .calc-row { display: flex; align-items: center; gap: 0.75rem; margin-bottom: 0.75rem; flex-wrap: wrap; } .calc-row label { min-width: 160px; font-size: 0.9rem; color: #333; font-weight: 500; } .calc-row input[type="number"], .calc-row select { flex: 1; min-width: 120px; max-width: 200px; padding: 0.5rem 0.6rem; border: 1px solid #ccc; border-radius: 4px; font-size: 0.9rem; font-family: system-ui, sans-serif; color: #1a1a1a; background: #fafaf8; } .calc-row input:focus, .calc-row select:focus { outline: none; border-color: var(--ac, #3d5a80); box-shadow: 0 0 0 2px rgba(26,74,138,0.12); } .calc-row .unit { font-size: 0.82rem; color: #888; min-width: 30px; } .calc-btn { display: inline-block; margin-top: 0.5rem; padding: 0.55rem 1.5rem; background: var(--ac, #3d5a80); color: #fff; border: none; border-radius: 4px; font-size: 0.9rem; font-weight: 600; cursor: pointer; font-family: system-ui, sans-serif; } .calc-btn:hover { opacity: 0.9; } .calc-result { margin-top: 1.25rem; padding: 1rem 1.25rem; background: #f0f6fc; border-left: 3px solid var(--ac, #3d5a80); border-radius: 0 6px 6px 0; display: none; } .calc-result.visible { display: block; } .calc-result-label { font-size: 0.78rem; text-transform: uppercase; letter-spacing: 0.06em; color: #666; margin-bottom: 0.25rem; } .calc-result-value { font-size: 1.6rem; font-weight: 700; color: var(--ac, #3d5a80); } .calc-result-detail { font-size: 0.85rem; color: #555; margin-top: 0.5rem; line-height: 1.5; } .calc-note { margin-top: 1rem; font-size: 0.8rem; color: #888; font-style: italic; } .calc-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 0.75rem; margin-top: 0.75rem; } .calc-grid-item { padding: 0.6rem 0.8rem; background: #f8f9fa; border-radius: 4px; border: 1px solid #eee; } .calc-grid-item .label { font-size: 0.75rem; color: #888; text-transform: uppercase; letter-spacing: 0.04em; } .calc-grid-item .value { font-size: 1.1rem; font-weight: 600; color: #1a1a1a; } @media (max-width: 720px) { .calc-row { flex-direction: column; align-items: flex-start; gap: 0.3rem; } .calc-row label { min-width: auto; } .calc-row input[type="number"], .calc-row select { max-width: 100%; width: 100%; } .calc-grid { grid-template-columns: 1fr; } } .calc-chart { margin: 1rem 0; text-align: center; } .calc-chart svg { max-width: 100%; height: auto; } .calc-chart-legend { display: flex; flex-wrap: wrap; justify-content: center; gap: 0.6rem 1.2rem; margin-top: 0.6rem; font-size: 0.8rem; color: #555; } .calc-chart-legend span { display: inline-flex; align-items: center; gap: 0.3rem; } .calc-chart-legend i { display: inline-block; width: 10px; height: 10px; border-radius: 2px; font-style: normal; } .calc-related { max-width: 640px; margin: 2rem 0 1rem; padding: 1.25rem 1.5rem; background: #f8f9fa; border: 1px solid #e8e8e8; border-radius: 8px; } .calc-related h3 { font-family: Georgia, serif; font-size: 1rem; color: #1a1a1a; margin: 0 0 0.75rem; padding-bottom: 0.4rem; border-bottom: 2px solid var(--ac, #3d5a80); } .calc-related-list { list-style: none; padding: 0; margin: 0 0 0.75rem; display: grid; grid-template-columns: 1fr 1fr; gap: 0.4rem 1.5rem; } .calc-related-list li a { font-size: 0.88rem; color: var(--ac, #3d5a80); text-decoration: none; } .calc-related-list li a:hover { text-decoration: underline; } .calc-browse-all { margin: 0.5rem 0 0; font-size: 0.9rem; font-weight: 600; } .calc-browse-all a { color: var(--ac, #3d5a80); text-decoration: none; } .calc-browse-all a:hover { text-decoration: underline; } @media (max-width: 720px) { .calc-related-list { grid-template-columns: 1fr; } }
Pergola or Shade Structure Material Calculator
Calculate the number of posts, beams, rafters, and optional shade cloth needed to build a pergola or shade structure.
Structure Length (ft)
Structure Width (ft)
Post Height (ft)
Post Spacing Along Length (ft)
Rafter Spacing (in)
Post Size
4×4 6×6
Beam Size
2×8 (doubled) 2×10 (doubled) 2×12 (doubled)
Rafter Size
2×6 2×8 2×10
Include Shade Cloth?
No Yes
Waste Factor (%)
Calculate
function perCalc() { var length = parseFloat(document.getElementById('per-length').value); var width = parseFloat(document.getElementById('per-width').value); var postHeight = parseFloat(document.getElementById('per-post-height').value); var postSpacing = parseFloat(document.getElementById('per-post-spacing').value); var rafterSpacIn = parseFloat(document.getElementById('per-rafter-spacing').value); var wastePct = parseFloat(document.getElementById('per-waste').value); var shadeCloth = document.getElementById('per-shade-cloth').value; var postSize = document.getElementById('per-post-size').value; var beamSize = document.getElementById('per-beam-size').value; var rafterSize = document.getElementById('per-rafter-size').value;
var errors = []; if (isNaN(length) || length 16) errors.push("Post spacing must be between 4 and 16 ft."); if (isNaN(rafterSpacIn) || rafterSpacIn 48) errors.push("Rafter spacing must be between 12 and 48 inches."); if (isNaN(wastePct) || wastePct 30) errors.push("Waste factor must be between 0 and 30%."); if (postSpacing > length) errors.push("Post spacing cannot exceed structure length."); if (postSpacing > width) errors.push("Post spacing cannot exceed structure width.");
if (errors.length > 0) { document.getElementById('per-result').innerHTML = ''; return; }
var wasteFactor = 1 + wastePct / 100;
// ── Posts ────────────────────────────────────────────────────────────────── // Posts run along both the length and width perimeter at postSpacing intervals. // postsAlongLength = floor(length / postSpacing) + 1 (per side, 2 sides) // postsAlongWidth = floor(width / postSpacing) + 1 (per side, 2 sides) // Corner posts are shared, so total = 2*(postsAlongLength + postsAlongWidth) - 4 var postsAlongLength = Math.floor(length / postSpacing) + 1; var postsAlongWidth = Math.floor(width / postSpacing) + 1; var totalPosts = 2 * (postsAlongLength + postsAlongWidth) - 4; var postBoardFt = Math.ceil(totalPosts * postHeight * wasteFactor);
// ── Beams ────────────────────────────────────────────────────────────────── // Beams run along the length on both sides (2 beams), each doubled → 4 boards. // Beams also run along the width on both sides (2 beams), each doubled → 4 boards. // Total beam boards = 4 * (length + width) linear ft, then apply waste. var beamBoards = 4; // doubled on each of 4 sides var beamLinearFt = 2 * (length + width); // total linear ft of beam runs var beamBoardFt = Math.ceil(beamLinearFt * 2 * wasteFactor); // ×2 for doubled beams
// ── Rafters ──────────────────────────────────────────────────────────────── // Rafters span the width, spaced rafterSpacIn inches apart along the length. // Number of rafters = floor(length / (rafterSpacIn/12)) + 1 var rafterSpacFt = rafterSpacIn / 12; var numRafters = Math.floor(length / rafterSpacFt) + 1; var rafterBoardFt = Math.ceil(numRafters * width * wasteFactor);
// ── Shade Cloth ──────────────────────────────────────────────────────────── var shadeSqFt = 0; if (shadeCloth === 'yes') { shadeSqFt = Math.ceil(length * width * wasteFactor); }
// ── Hardware (approximate) ───────────────────────────────────────────────── // Post anchors: one per post // Joist hangers: two per rafter (both ends) // Lag screws: 4 per post-beam connection var postAnchors = totalPosts; var joistHangers = numRafters * 2; var lagScrews = totalPosts * 4;
// ── Concrete (for post footings) ─────────────────────────────────────────── // Rule of thumb: 1 bag (60 lb) of concrete per post for standard residential pergola var concreteBags = totalPosts;
// ── Build result HTML ────────────────────────────────────────────────────── var html = '### Material Estimate '; html += ''; html += 'MaterialQuantityNotes'; html += '' + postSize + ' Posts' + totalPosts + ' posts / ' + postBoardFt + ' board-ft' + postHeight + ' ft each, ' + postSpacing + ' ft spacing'; html += '' + beamSize + ' Beams (doubled)' + beamBoardFt + ' board-ftPerimeter beams, doubled for strength'; html += '' + rafterSize + ' Rafters' + numRafters + ' rafters / ' + rafterBoardFt + ' board-ft' + rafterSpacIn + '" o.c., spanning ' + width + ' ft'; if (shadeCloth === 'yes') { html += 'Shade Cloth' + shadeSqFt + ' sq ftIncludes ' + wastePct + '% waste'; } html += 'Post Anchors / Bases' + postAnchors + ' pcsOne per post'; html += 'Joist Hangers' + joistHangers + ' pcsTwo per rafter'; html += 'Lag Screws (3/8" × 3")' + lagScrews + ' pcs4 per post-beam connection'; html += 'Concrete (60 lb bags)' + concreteBags + ' bagsOne per post footing'; html += '';
html += '### Structure Summary '; html += ''; html += 'ParameterValue'; html += 'Footprint' + length + ' ft × ' + width + ' ft = ' + (length * width).toFixed(1) + ' sq ft'; html += 'Post Height' + postHeight + ' ft'; html += 'Posts Along Length (per side)' + postsAlongLength + ''; html += 'Posts Along Width (per side)' + postsAlongWidth + ''; html += 'Total Posts' + totalPosts + ''; html += 'Total Rafters' + numRafters + ''; html += 'Waste Factor Applied' + wastePct + '%'; html += '';
document.getElementById('per-result').innerHTML = html; }
#### Formulas Used
Posts per side (length): ⌊Length ÷ Post Spacing⌋ + 1
Posts per side (width): ⌊Width ÷ Post Spacing⌋ + 1
Total Posts: 2 × (Posts Along Length + Posts Along Width) − 4 (corners shared)
Post Board-Feet: Total Posts × Post Height × Waste Factor
Beam Board-Feet: 2 × (Length + Width) × 2 (doubled) × Waste Factor
Number of Rafters: ⌊Length ÷ (Rafter Spacing in ft)⌋ + 1
Rafter Board-Feet: Number of Rafters × Width × Waste Factor
Shade Cloth (sq ft): Length × Width × Waste Factor
Waste Factor: 1 + (Waste % ÷ 100)
#### Assumptions & References
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