Fence Line Length and Grade Slope Calculator

ANA›Life Services Authority›National Calculator Authority›Fence Line Length and Grade Slope 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; } }

Fence Line Length and Grade Slope Calculator

Calculate the true slope length of a fence line, grade percentage, slope angle, and number of posts needed based on horizontal distance and elevation change.

Horizontal Distance (ft)

Elevation Change / Rise (ft)

Post Spacing (ft)

Number of Fence Sections (runs)

Calculate

function fenCalc() { var horiz = parseFloat(document.getElementById('fen-horiz').value); var elev = parseFloat(document.getElementById('fen-elev').value); var spacing = parseFloat(document.getElementById('fen-spacing').value); var sections = parseInt(document.getElementById('fen-sections').value);

var errors = []; if (isNaN(horiz) || horiz horiz * 10) errors.push("Elevation change seems unrealistically large relative to horizontal distance.");

var resultDiv = document.getElementById('fen-result'); if (errors.length > 0) { resultDiv.style.display = 'block'; resultDiv.innerHTML = 'Input Error:' + errors.map(function(e){ return ''; }).join('') + ''; return; }

// ── Core formulas ────────────────────────────────────────────────────────── // Slope (true) length: L = sqrt(H² + R²) var slopeLength = Math.sqrt(horiz * horiz + elev * elev);

// Grade percentage: G% = (R / H) × 100 var gradePct = (elev / horiz) * 100;

// Slope angle in degrees: θ = atan(R / H) var angleRad = Math.atan2(elev, horiz); var angleDeg = angleRad * (180 / Math.PI);

// Posts per section (slope length basis): // posts = floor(slopeLength / spacing) + 1 (one post at each end) var postsPerSection = Math.floor(slopeLength / spacing) + 1;

// Total for all sections (shared end posts between sections not assumed): var totalPosts = postsPerSection * sections;

// Total slope length across all sections: var totalSlope = slopeLength * sections;

// Fence panels (spaces between posts) per section: var panelsPerSection = postsPerSection - 1; var totalPanels = panelsPerSection * sections;

// Racking angle (angle fence panels must be racked): // same as slope angle for a racked fence var rackAngleDeg = angleDeg;

// ── Grade classification ─────────────────────────────────────────────────── var gradeClass = ""; if (gradePct ' + row("Horizontal Distance", fmt(horiz, 2) + " ft") + row("Elevation Change (Rise)", fmt(elev, 2) + " ft") + row("True Slope Length (per run)", '' + fmt(slopeLength, 2) + ' ft') + row("Total Slope Length (" + sections + " run" + (sections>1?"s":"") + ")", '' + fmt(totalSlope, 2) + ' ft') + row("Grade / Slope Percentage", '' + fmt(gradePct, 2) + '%') + row("Slope Angle", fmt(angleDeg, 2) + "°") + row("Racking Angle", fmt(rackAngleDeg, 2) + "°") + row("Post Spacing", fmt(spacing, 2) + " ft") + row("Posts per Run", postsPerSection + " posts") + row("Total Posts (" + sections + " run" + (sections>1?"s":"") + ")", totalPosts + " posts") + row("Fence Panels per Run", panelsPerSection + " panels") + row("Total Fence Panels", totalPanels + " panels") + '' + '' + 'Grade Assessment: ' + gradeClass + '

'; }

function row(label, value) { return '' + '' + label + '' + '' + value + ''; }

function fmt(n, d) { return n.toLocaleString('en-US', {minimumFractionDigits: d, maximumFractionDigits: d}); }

#### Formulas Used

True Slope Length (Pythagorean Theorem): L = √(H² + R²) where H = horizontal distance, R = rise (elevation change).

Grade Percentage: G% = (R ÷ H) × 100

Slope Angle: θ = arctan(R ÷ H)

Posts per Run: Posts = floor(L ÷ spacing) + 1

Fence Panels per Run: Panels = Posts − 1

#### Assumptions & References

More Calculators

Read Next

Study Time Planner Authority Network America › Life Services Authority › National Calculator Authority .calc-container { max-width: 640px;...

References

Related Authorities

Life Services Authority › Professional Services Authority › Trade Services Authority › United States Authority ›