Recessed Lighting Calculator

How many recessed lights do you need? Enter your room dimensions and ceiling height — this free calculator gives you the can light count, spacing and layout grid using the standard electrician's spacing rule. Runs entirely in your browser.

How recessed lighting layout works

The standard rule: spacing = ceiling height ÷ 2 for general ambient lighting. An 8-foot ceiling means lights roughly 4 feet apart; a 10-foot ceiling means 5 feet apart. Task areas (kitchens, home offices) get tighter spacing — about ceiling height ÷ 2.5. Divide each room dimension by the spacing and round up to get your rows and columns.

FAQ

How far should recessed lights be from the wall?

2–3 feet is the standard. Closer than 2 feet creates harsh "scallop" hot spots on the wall; farther than 3 feet leaves dark corners.

What size recessed lights should I use?

4-inch LED downlights are the modern default for most rooms (brighter and more efficient than old 6-inch cans). 6-inch still works for high ceilings over 10 feet.

How many lumens per square foot do I need?

Around 20 lumens per square foot for ambient living-space lighting, 30–40+ for kitchens and task areas. The calculator shows your estimated total so you can compare.

Can I install these myself?

Retrofit canless LED wafer lights are DIY-friendly if you are comfortable with basic wiring — but new circuits and anything involving the breaker panel should go to a licensed electrician.