LayoutWise

Recessed Lighting Layout Calculator

Enter the room and ceiling height. You get how many recessed lights to install, exactly where they go on the ceiling, and whether the room will be bright enough.

Your room

1. Room
Length
ft
in
Width
ft
in
Ceiling height
ft
in
2. Lights

Lights

12

4 x 3 grid

Spacing

4 ft

ceiling ÷ 2 = 4 ft

From walls

2 ft

half the spacing

Brightness

44 fc

target 15 fc

⚠ That is brighter than most people want — put the lights on a dimmer.

Ceiling plan

Circles show roughly where each beam lands

Lights sit 2 ft from the walls and 4 ft apart. Move a row slightly to miss a joist, and keep lights at least 12" from cabinet faces in a kitchen.

Shopping list

  • ✓6" LED recessed lights: 12 (about 1000 lumens each), IC-rated if they touch insulation
  • ✓14/2 NM cable: about 89 ft (check your circuit — 15 A circuits use 14-gauge)
  • ✓One LED-compatible dimmer switch, a switch box, and wire connectors (2 per light)
  • ✓Hole saw or the template that comes with the lights, and a stud finder to dodge joists

Brightness uses a typical 70% of the lamp's lumens reaching the floor. If you aren't comfortable working with house wiring, hire a licensed electrician — many towns require a permit.

How far apart should recessed lights be?

Lighting makers use a simple starting rule: "divide your ceiling height by 2" to get the space between lights, and keep it no more than about 6 feet. An 8-foot ceiling gets lights about 4 feet apart; a 10-foot ceiling about 5 feet. The first row sits half that distance from the wall, so light washes the walls instead of leaving dark edges.

Example: a 16' x 12' living room with an 8-foot ceiling. Four feet of spacing gives a 4 x 3 grid — 12 lights, the first ones 2 feet in from the walls.

Is it bright enough?

Brightness on the floor is measured in foot-candles. Typical targets are 10–20 for living rooms and bedrooms, 20–30 for bathrooms, and 30–50 for kitchens and work areas. The planner assumes about 70% of each light's lumens reach the floor. With 1,000-lumen 6" lights, the 12-light living room gets about 44 foot-candles — bright, so put them on a dimmer.

4" or 6" lights?

Smaller 4" trims look cleaner and suit lower ceilings and accent lighting; 6" trims put out more light each, so you need fewer. In kitchens, keep lights about 12" out from the cabinet faces so they light the counter, not the top of your head.

Wiring

Most lighting circuits are 15 A, wired with 14-gauge cable. Use IC-rated fixtures where they touch insulation. Wiring rules and permits vary by town; if you aren't sure, hire a licensed electrician.

Sources