Recessed Lighting Calculator

Plan the perfect lighting layout for any room. Get the right number of lights and spacing.

Expert-Designed Lighting Plans

Developed with certified lighting designers. Based on IESNA standards. Used by 15,000+ homeowners monthly.

Recommended Lighting Plan

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Number of Lights

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Spacing Between Lights

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First Row From Wall

Suggested Layout

Installation Tips

How to Use This Calculator

Enter your room dimensions
Select ceiling height
Choose bulb type and room use
Click “Calculate”
See recommended layout

Understanding Recessed Lighting

Proper spacing is key for good lighting:

General lighting: 4-6 feet between lights
Task lighting: 3-4 feet between lights
Accent lighting: 2-3 feet between lights

Lights should be placed 2-3 feet from walls.

Lighting Designer Tip

“For best results, layer your lighting. Combine recessed lights with lamps or sconces. This creates depth and flexibility.”

– James Wilson, Certified Lighting Designer (CLD)

Recessed Light Calculator : How to Get Perfect Lighting for Any Room

Installing recessed lights can transform your space. But how many do you need? Where should you place them? A recessed light calculator makes this easy.

In this guide, you’ll learn:
✅ How to calculate the number of recessed lights needed
✅ The best spacing and placement for even lighting
✅ Wattage, beam angle, and brightness tips
✅ Free online tools and formulas

Let’s get started.

What Is a Recessed Light Calculator?

A recessed light calculator helps you determine:

How many lights your room needs
Where to place them for balanced lighting
The right brightness (lumens) and beam angle

Without a calculator, you might end up with:
❌ Too few lights → Dark spots
❌ Too many lights → Harsh, uneven lighting
❌ Wrong spacing → Glare or shadows

Using a calculator ensures perfect lighting every time.

How to Calculate Recessed Lighting (Step-by-Step)

Step 1: Measure Your Room

First, find:

Room length (in feet)
Room width (in feet)
Ceiling height (standard is 8-10 ft)

Example: A 12 ft x 15 ft room with an 8 ft ceiling.

Step 2: Determine Light Spacing

A simple rule:

Divide ceiling height by 2 = Spacing between lights
Example: 8 ft ceiling ÷ 2 = 4 ft apart

For larger rooms:

Keep spacing 4-6 ft for even coverage
Avoid placing lights too close to walls (stay 2-3 ft away)

Step 3: Calculate Number of Lights Needed

Use this formula:

(Length ÷ Spacing) × (Width ÷ Spacing) = Number of Lights

Example:

Room: 12 ft × 15 ft
Spacing: 4 ft
Calculation: (12 ÷ 4) × (15 ÷ 4) = 3 × 3.75 → 12 lights (round up)

Step 4: Adjust for Brightness (Lumens & Wattage)

Lumens = Total Light Output
Wattage = Energy Used

Recommended Brightness:

Room Type	Lumens per Sq Ft
Living Room	15-20
Kitchen	30-40
Bedroom	10-15
Bathroom	70-80 (task lighting)

Example:

A 180 sq ft living room needs 2,700-3,600 lumens (180 × 15-20).
If using 800-lumen bulbs → 4-5 lights (3,600 ÷ 800).

Step 5: Choose the Right Beam Angle

Narrow beam (25°-45°) → Spotlighting (art, kitchen islands)
Wide beam (60°-120°) → General room lighting

Common Mistakes to Avoid

❌ Ignoring ceiling height → Wrong spacing
❌ Using only one formula → Adjust for room use (kitchen vs. bedroom)
❌ Forgetting dimmers → No flexibility in brightness

Final Tips for Perfect Recessed Lighting

✔ Use LED bulbs – Energy-efficient, long-lasting
✔ Layer lighting – Combine recessed lights with lamps
✔ Test before installing – Use a flashlight to simulate placement

Conclusion

A recessed light calculator takes the guesswork out of lighting design. Measure your room, use the right formula, and avoid common mistakes.

Need help? Try an online calculator or consult an electrician.