ADA Compliance Ramp and Accessibility Calculator

ANA›Life Services Authority›National Calculator Authority›ADA Compliance Ramp and Accessibility 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; } }

ADA Compliance Ramp and Accessibility Calculator

Calculate ADA-compliant ramp dimensions based on rise height, including required ramp length, slope ratio, landing requirements, and handrail specifications per the ADA Standards for Accessible Design (Section 405).

Vertical Rise (inches) *

Total height the ramp must overcome

Ramp Width (inches)

Minimum ADA requirement: 36 inches clear width

Slope Ratio to Use

1:12 (Standard ADA Maximum — 8.33%) 1:16 (Preferred — 6.25%) 1:20 (Gentle — 5%)

1:12 is the maximum allowed slope per ADA Section 405.2

Landing Width (inches)

Minimum ADA requirement: 60 inches square at top and bottom

Calculate

function adaCalc() { const resultDiv = document.getElementById('ada-result');

// --- Inputs --- const rise = parseFloat(document.getElementById('ada-rise').value); const width = parseFloat(document.getElementById('ada-width').value); const slopeRatio = parseFloat(document.getElementById('ada-slope-choice').value); const landingWidth = parseFloat(document.getElementById('ada-landing-width').value);

// --- Validation --- const errors = [];

if (isNaN(rise) || rise 360) { errors.push("Vertical Rise exceeds 360 inches (30 ft). Consider multiple ramp runs."); }

if (isNaN(width) || width 0) { resultDiv.innerHTML = 'Please fix the following:' + errors.map(e => '').join('') + ''; return; }

// --- Core Calculations --- // ADA Section 405.2: Max slope 1:12 (rise:run) // Run = Rise × Slope Ratio const runInches = rise * slopeRatio; const runFeet = runInches / 12;

// Slope percentage const slopePercent = (1 / slopeRatio) * 100;

// Slope angle in degrees const slopeAngleDeg = Math.atan(1 / slopeRatio) * (180 / Math.PI);

// ADA Section 405.6: Max rise per ramp run = 30 inches // Number of ramp runs needed const maxRisePerRun = 30; // inches const numberOfRuns = Math.ceil(rise / maxRisePerRun); const risePerRun = rise / numberOfRuns; const runPerSegment = risePerRun * slopeRatio;

// Intermediate landings needed (between runs) const intermediateLandings = numberOfRuns - 1;

// Landing length: minimum 60 inches per ADA Section 405.7.1 const landingLength = 60; // inches minimum

// Total horizontal distance including landings // Total run + (number of landings × landing length) // Landings: 1 at top + 1 at bottom + intermediate const totalLandings = numberOfRuns + 1; // top + bottom + intermediate const totalHorizontalInches = runInches + (totalLandings * landingLength); const totalHorizontalFeet = totalHorizontalInches / 12;

// Ramp surface area (run only, not landings) const rampSurfaceAreaSqFt = (runInches / 12) * (width / 12);

// Total surface area including landings const landingSqFt = (landingWidth / 12) * (landingLength / 12); const totalSurfaceAreaSqFt = rampSurfaceAreaSqFt + (totalLandings * landingSqFt);

// Handrail requirement: ADA Section 505 // Required if rise > 6 inches const handrailRequired = rise > 6; // Handrail height: 34–38 inches above ramp surface const handrailHeightMin = 34; const handrailHeightMax = 38; // Handrail extension beyond ramp: 12 inches horizontal at top, 12 inches + slope extension at bottom const handrailTopExtension = 12; // inches horizontal const handrailBottomExtension = 12 + runPerSegment; // per ADA 505.10.3

// Edge protection: ADA Section 405.9 // Required: curb, wall, or barrier at least 4 inches high const edgeProtectionHeight = 4; // inches minimum

// Cross slope: ADA Section 405.3 — max 1:48 (2.08%) const maxCrossSlope = (1/48) * 100;

// Width compliance check const widthCompliant = width >= 36; const landingCompliant = landingWidth >= 60; const slopeCompliant = slopeRatio >= 12; // 1:12 or gentler

// --- Compliance Status --- const isCompliant = widthCompliant && landingCompliant && slopeCompliant;

// --- Format helpers ---

function fmtIn(val)

function fmtFt(val)

function fmtPct(val)

function fmtDeg(val)

function fmtSqFt(val)

function badge(ok) {

return ok

? '✔ Compliant'

'✘ Non-Compliant'; }

// --- Output --- resultDiv.innerHTML = ` ### ADA Ramp Compliance Results

Overall Status: ${isCompliant ? '✔ ADA Compliant Design' : '✘ Design Requires Adjustment'}

ParameterValueADA RequirementStatus

Vertical Rise ${fmtIn(rise)} (${(rise/12).toFixed(2)} ft) Max 30 in per run ${badge(risePerRun

Slope Ratio 1:${slopeRatio} (${fmtPct(slopePercent)}) Max 1:12 (8.33%) ${badge(slopeCompliant)}

Slope Angle ${fmtDeg(slopeAngleDeg)} Max 4.76° (1:12) ${badge(slopeAngleDeg

Total Ramp Run Length ${fmtIn(runInches)} (${fmtFt(runFeet)}) Rise × Slope Ratio —

Number of Ramp Runs ${numberOfRuns} Required if rise > 30 in ${badge(numberOfRuns >= 1)}

Rise per Run ${fmtIn(risePerRun)} Max 30 in per run ${badge(risePerRun

Run Length per Segment ${fmtIn(runPerSegment)} (${(runPerSegment/12).toFixed(2)} ft) Rise per run × Slope Ratio —

Intermediate Landings ${intermediateLandings} Required between runs ${badge(true)}

Total Landings (incl. top & bottom) ${totalLandings} Min 60 × 60 in each ${badge(true)}

Ramp Clear Width ${fmtIn(width)} Min 36 in ${badge(widthCompliant)}

Landing Width ${fmtIn(landingWidth)} Min 60 in ${badge(landingCompliant)}

Landing Length ${fmtIn(landingLength)} Min 60 in ${badge(true)}

Total Horizontal Distance ${fmtIn(totalHorizontalInches)} (${fmtFt(totalHorizontalFeet)}) Run + all landings —

Ramp Surface Area ${fmtSqFt(rampSurfaceAreaSqFt)} Run × Width —

Total Surface Area (incl. landings) ${fmtSqFt(totalSurfaceAreaSqFt)} Ramp + all landings —

Handrails Required ${handrailRequired ? 'Yes (both sides)' : 'Not required (rise ≤ 6 in)'} Required if rise > 6 in ${badge(true)}

${handrailRequired ? `

Handrail Height ${handrailHeightMin}–${handrailHeightMax} in above surface 34–38 in (ADA 505.4) ${badge(true)}

Handrail Top Extension ${fmtIn(handrailTopExtension)} horizontal Min 12 in (ADA 505.10.2) ${badge(true)}

Handrail Bottom Extension ${fmtIn(handrailBottomExtension)} 12 in + ramp run (ADA 505.10.3) ${badge(true)} ` : ''}

Max Cross Slope ${fmtPct(maxCrossSlope)} Max 2.08% (1:48) ${badge(true)}

Edge Protection Height Min ${edgeProtectionHeight} in curb/barrier Min 4 in (ADA 405.9) ${badge(true)}

${!isCompliant ? `

⚠ Corrections Needed:

${!widthCompliant ? '' : ''} ${!landingCompliant ? '' : ''} ${!slopeCompliant ? '' : ''}

: ''}; }

#### Formulas Used

Ramp Run Length: Run = Rise × Slope Ratio (e.g., Rise × 12 for 1:12 slope)

Slope Percentage: Slope% = (1 ÷ Slope Ratio) × 100

Slope Angle: θ = arctan(1 ÷ Slope Ratio) × (180 ÷ π)

Number of Runs: Runs = ⌈Rise ÷ 30⌉ (ceiling division; max 30 in rise per run)

Rise per Run: Rise per Run = Total Rise ÷ Number of Runs

Total Horizontal Distance: Total = Run + (Total Landings × 60 in)

Ramp Surface Area: Area = (Run ÷ 12) × (Width ÷ 12) in square feet

Handrail Bottom Extension: Extension = 12 in + Run Length per Segment

#### Assumptions & References

• ADA Section 405.2: Maximum ramp slope is 1:12 (8.33%). Slopes between 1:16 and 1:20 are preferred where space allows.
• ADA Section 405.5: Minimum clear ramp width is 36 inches between handrails.
• ADA Section 405.6: Maximum rise for any single ramp run is 30 inches. Multiple runs with intermediate landings are required for greater rises.
• ADA Section 405.7: Landings must be at least 60 × 60 inches at the top and bottom of each ramp run and at any change of direction.
• ADA Section 405.3: Cross slope of ramp surfaces must not exceed 1:48 (2.08%).
• ADA Section 405.9: Edge protection (curb, wall, or barrier) of at least 4 inches is required on all non-wall sides of ramp surfaces and landings.
• ADA Section 505.2: Handrails are required on both sides of ramps with a rise greater than 6 inches.
• ADA Section 505.4: Handrail gripping surfaces must be 34–38 inches above the ramp surface.
• ADA Section 505.10: Handrails must extend 12 inches horizontally beyond the top of the ramp and 12 inches plus the ramp run beyond the bottom.
• This calculator is based on the 2010 ADA Standards for Accessible Design published by the U.S. Department of Justice.

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References

• 1 CFR § 457.149 — § 457.149 Program accessibility: Discrimination prohibited
• 1 CFR § 457.150 — § 457.150 Program accessibility: Existing facilities
• 1 CFR § 457.151 — § 457.151 Program accessibility: New construction and alterations