Recessed Lighting Spacing Calculator

Professional Layout & Quantity Planning Tool

Room Length (ft)

Room Width (ft)

Ceiling Height (ft)

Recommended Layout

Total Fixtures 0

Grid Pattern 0 x 0

Space Between Lights 0′

Distance from Wall 0′

How to Spacing Recessed Lighting

Planning the perfect recessed lighting layout (often called can lights or pot lights) is essential for achieving balanced illumination without shadows or "hot spots." The key to professional lighting design lies in the relationship between your ceiling height and the distance between fixtures.

The "Half the Ceiling Height" Rule

The standard industry rule of thumb is to space your lights apart at a distance equal to half the height of your ceiling. For example, if you have 8-foot ceilings, your lights should be spaced approximately 4 feet apart. If you have 10-foot ceilings, you should aim for 5 feet of spacing.

Wall Clearance and Corner Placement

To avoid harsh shadows and a "cave effect" on your walls, follow these guidelines:

The Half-Distance Rule: The distance from the wall to the first light should be exactly half of the distance between the lights. If your lights are 4 feet apart, place the first row 2 feet from the wall.
Task Lighting: In kitchens, align lights with the edge of the countertop (usually 24-26 inches from the wall) to prevent working in your own shadow.
Focal Points: Adjust spacing if you need to highlight artwork, a fireplace, or architectural features.

Layout Example

For a 12′ x 15′ room with 8′ ceilings:

Ceiling Height: 8 feet (Suggests 4′ spacing).
Width Layout: 12 / 4 = 3 rows. Space = 4′ between, 2′ from walls.
Length Layout: 15 / 4 = 3.75 (Round to 4). Space = 3.75′ between, 1.8′ from walls.
Total: 12 fixtures in a 3×4 grid.

function calculateLighting() { var length = parseFloat(document.getElementById('roomLength').value); var width = parseFloat(document.getElementById('roomWidth').value); var height = parseFloat(document.getElementById('ceilingHeight').value); if (isNaN(length) || isNaN(width) || isNaN(height) || length <= 0 || width <= 0 || height <= 0) { alert("Please enter valid positive numbers for all dimensions."); return; } // Standard rule: spacing = height / 2 var idealSpacing = height / 2; // Calculate columns (across width) var cols = Math.max(1, Math.round(width / idealSpacing)); var actualSpacingWidth = width / cols; var wallDistWidth = actualSpacingWidth / 2; // Calculate rows (across length) var rows = Math.max(1, Math.round(length / idealSpacing)); var actualSpacingLength = length / rows; var wallDistLength = actualSpacingLength / 2; var totalLights = rows * cols; // Update Display document.getElementById('resTotalLights').innerText = totalLights; document.getElementById('resGrid').innerText = rows + " x " + cols; // Formatting average spacing var avgSpacing = ((actualSpacingWidth + actualSpacingLength) / 2).toFixed(1); var avgWall = ((wallDistWidth + wallDistLength) / 2).toFixed(1); document.getElementById('resSpacing').innerText = avgSpacing + " ft"; document.getElementById('resWallDist').innerText = avgWall + " ft"; // Dynamic Advice var advice = "Based on your " + height + "' ceiling, we recommend a " + rows + "x" + cols + " grid. "; advice += "Place the first row approximately " + avgWall + "' from the wall, then space fixtures " + avgSpacing + "' apart."; document.getElementById('lightingAdvice').innerText = advice; document.getElementById('lightingResults').style.display = 'block'; }