Paint Cost Estimator
ANA›Life Services Authority›National Calculator Authority›Paint Cost Estimator
.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; } }
Paint Cost Estimator
Estimate how much paint you need and the total cost based on room dimensions, paint coverage rate, number of coats, and price per gallon.
Room Length (ft)
Room Width (ft)
Wall Height (ft)
Number of Doors (standard 20 sq ft each)
Number of Windows (standard 15 sq ft each)
Number of Coats
Paint Coverage Rate (sq ft per gallon)
Price per Gallon ($)
Calculate
function paiCalc() { var length = parseFloat(document.getElementById('pai-length').value); var width = parseFloat(document.getElementById('pai-width').value); var height = parseFloat(document.getElementById('pai-height').value); var doors = parseFloat(document.getElementById('pai-doors').value) || 0; var windows = parseFloat(document.getElementById('pai-windows').value) || 0; var coats = parseFloat(document.getElementById('pai-coats').value); var coverage = parseFloat(document.getElementById('pai-coverage').value); var price = parseFloat(document.getElementById('pai-price').value);
var resultDiv = document.getElementById('pai-result');
if (isNaN(length) || length Please enter a valid room length (must be > 0).'; return; } if (isNaN(width) || width Please enter a valid room width (must be > 0).'; return; } if (isNaN(height) || height Please enter a valid wall height (must be > 0).'; return; } if (isNaN(coats) || coats Number of coats must be at least 1.'; return; } if (isNaN(coverage) || coverage Coverage rate must be at least 100 sq ft/gallon.'; return; } if (isNaN(price) || price Please enter a valid price per gallon (must be > 0).'; return; } if (doors Doors and windows cannot be negative.'; return; }
// Wall area = perimeter × height var perimeter = 2 * (length + width); var grossWall = perimeter * height;
// Subtract door and window areas var doorArea = doors * 20; var windowArea = windows * 15; var netWall = grossWall - doorArea - windowArea;
if (netWall Net wall area is zero or negative. Reduce the number of doors/windows.'; return; }
// Total area to paint (accounting for coats) var totalArea = netWall * coats;
// Gallons needed (round up to nearest whole gallon) var gallonsExact = totalArea / coverage; var gallonsNeeded = Math.ceil(gallonsExact);
// Total cost var totalCost = gallonsNeeded * price;
resultDiv.innerHTML = 'Results:' + 'Gross Wall Area: ' + grossWall.toFixed(1) + ' sq ft' + 'Area Deducted (doors + windows): ' + (doorArea + windowArea).toFixed(1) + ' sq ft' + 'Net Paintable Wall Area: ' + netWall.toFixed(1) + ' sq ft' + 'Total Area to Cover (' + coats + ' coat' + (coats > 1 ? 's' : '') + '): ' + totalArea.toFixed(1) + ' sq ft' + 'Paint Required (exact): ' + gallonsExact.toFixed(2) + ' gallons' + 'Paint to Purchase (rounded up): ' + gallonsNeeded + ' gallon' + (gallonsNeeded !== 1 ? 's' : '') + '' + 'Estimated Total Cost: $' + totalCost.toFixed(2) + ''; }
#### Formula
Gross Wall Area = 2 × (Length + Width) × Height Net Wall Area = Gross Wall Area − (Doors × 20 sq ft) − (Windows × 15 sq ft) Total Area = Net Wall Area × Number of Coats Gallons Needed = ⌈ Total Area ÷ Coverage Rate ⌉ (rounded up to whole gallons) Total Cost = Gallons Needed × Price per Gallon
#### Assumptions & References
- Standard interior door area assumed to be 20 sq ft (approx. 3 ft × 6.67 ft).
- Standard window area assumed to be 15 sq ft (approx. 3 ft × 5 ft).
- Default paint coverage of 350 sq ft per gallon is typical for interior latex paint (range: 250–400 sq ft/gallon depending on brand and surface porosity).
- Gallons are always rounded up to avoid running short mid-project.
- Ceiling and trim are not included; add separate calculations for those surfaces.
- Reference: Paint Quality Institute and major paint manufacturer guidelines (Sherwin-Williams, Benjamin Moore).
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