How many recessed lights do I need?

The number depends on your room size, ceiling height, and target brightness (foot-candles). Enter your dimensions and lumens per fixture to get a recommended fixture count.

What is a good lumen level per recessed light?

Many modern LED can lights provide 700–1000 lumens each. Kitchens and work areas need more light per fixture or more fixtures than bedrooms and living rooms.

Recessed Lighting Calculator - Fixture Count & Spacing

Unit System

U.S. users typically use feet/inches. Metric is available for convenience.

Room Length (ft)

Room Width (ft)

Ceiling Height (ft)

Room Type (target brightness)

Foot-candles (fc) are lumens per square foot.

Lumens per Fixture

Typical LED can lights: ~700–1000 lm.

Spacing Multiplier (× ceiling height)

Rule of thumb: 0.8 × ceiling height (ft).

Wall Offset (ft)

Distance from wall to first light center.

Layout Preview

Dots show approximate fixture centers. Grid scales to your inputs.

Recessed Lighting Calculator — Fast Planning for Can Lights

This free Recessed Lighting Calculator helps you plan how many recessed lights you need, how far apart to space them, and a quick rows × columns layout. It uses common foot-candle targets for different rooms and a practical spacing rule so your results are both simple and realistic.

How It Works

Enter room size: Length × width in feet (or metric).
Pick your room type: Sets a target brightness (foot-candles).
Enter lumens per fixture: Typical LED recessed lights are ~700–1000 lumens.
Use the spacing rule: Start with 0.8 × ceiling height for center-to-center spacing.
Review the layout preview: See an estimated rows × columns grid and wall offsets.

Quick Tips

Keep the first row of lights about 2–3 ft from the wall for even illumination.
Kitchens and work areas need more light (higher foot-candles or more lumens per fixture).
Use dimmers for flexibility—bright for tasks, lower for ambience.

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FAQs

How many can lights per room?
It depends on room area, target brightness, and lumens per fixture. The calculator gives a fixture count and layout suggestion instantly.

What spacing should I use for 8–9 ft ceilings?
A good starting point is 0.8 × ceiling height (about 6.5–7.2 ft center-to-center), with 2–3 ft off walls.

Do I need more light for kitchens?
Yes—kitchens and task areas typically target 40–80 fc, so either use more fixtures or choose higher-lumen trims.

Reviewed by Sonia Cho · Dec 2025 Methodology

Important Estimate Disclaimer

The results provided by this calculator are intended as general estimates only and should not be considered precise engineering measurements. Actual material requirements, costs, and quantities can vary significantly based on site conditions, local building codes, soil type, reinforcement requirements, climate exposure, and the intended use of your project.

These calculators are designed to help you plan and budget your project more effectively, but they do not replace professional advice from a qualified contractor, engineer, or building inspector. Always verify your calculations and assumptions with trained professionals before placing material orders or commencing construction.

For more information on the assumptions, formulas, and data used in these tools, see our Data Sources and Methodology pages.

Material estimates, cost figures, and volume calculations are approximate and may not reflect your actual requirements. Always double-check dimensions and project-specific needs, and consider adding a contingency allowance for waste, over-excavation, and unforeseen conditions.

If you are unsure about any aspect of your project — including structural requirements, reinforcement needs, drainage, or load-bearing capacity — consult with a licensed professional before proceeding.