Recessed Lighting Calculator | Determine Fixture Spacing

Unit System

Choose the units you’ll enter for room dimensions and wall offset.

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 recessed lights: ~700–1000 lm.

Spacing Multiplier (× ceiling height)

Rule of thumb: 0.8 × ceiling height (in your selected units).

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 your chosen units.
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 a spacing target.
Review the layout preview: See an estimated rows × columns grid and a starting wall offset.

Quick Tips

Keep the first row of lights about 2–3 ft (≈0.6–0.9 m) from the wall for even illumination.
Kitchens and work areas need more light (higher foot-candles or more fixtures).
Use dimmers for flexibility—bright for tasks, lower for ambience.
For wall wash or artwork, placement can be closer depending on beam angle and ceiling height.

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FAQs

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 spacing should I use?
A common rule of thumb is 0.8 × ceiling height (in feet) for center-to-center spacing. The calculator shows a spacing target and the grid spacing based on your rows × columns layout.

What is a good lumen level per recessed light?
Many modern LED recessed fixtures provide about 700–1000 lumens each. Kitchens and task areas often need more total light than bedrooms and living rooms.

How far from the wall should recessed lights be?
A common starting point is placing the first row about 2–3 ft from the wall for even illumination. For wall-wash lighting or artwork, you may place fixtures closer depending on beam angle and ceiling height.

Accuracy & Review

Reviewed by: Sonia Cho

Sonia reviews our lighting and electrical tools, validating spacing guidance, fixture density assumptions, and calculation logic for practical planning use.

Last updated: Feb 12, 2026

See: Methodology · Data Sources · Review Board

Important Estimate Disclaimer

These calculations are general estimates only and should not be used as final system design specifications. Actual sizing may vary based on demand requirements, code compliance, and manufacturer guidelines.

See our Methodology and Data Sources for calculation details.

Mechanical, plumbing, and electrical systems should be verified by qualified professionals prior to installation.