Recessed Lighting Calculator
Work out how many recessed lights a room needs and how far apart to space them for even ambient lighting, based on your room size and ceiling height. Add your own fixture price for a cost estimate.
How this calculator works
The calculator divides each room dimension by the spacing value to find how many fixtures fit in a row and column, then multiplies them for the total grid:
rows = ceil( room width ÷ spacing ) cols = ceil( room length ÷ spacing ) total lights = rows × cols inset from walls = spacing ÷ 2
The inset figure is a starting point for centering the grid — place the first row and column of lights that distance in from the walls so the layout reads as evenly spaced rather than crowding one edge.
Worked example
A 12 ft × 10 ft room, 8 ft ceilings, 8 ft spacing:
- Rows: ceil(10 ÷ 8) = 2.
- Columns: ceil(12 ÷ 8) = 2.
- Total lights: 2 × 2 = 4.
- Inset from walls: 8 ÷ 2 = 4 ft.
Ambient vs task lighting
This calculator lays out an even ambient grid — good for general room lighting. Task lighting works differently: it's placed deliberately over specific work areas like a kitchen island, reading chair, or vanity mirror, often spaced closer together and wired to its own switch so it can run independently of the general room lights. A kitchen commonly combines both — a tighter ambient grid over the main floor area plus dedicated task lights over counters and islands.
Choosing spacing by room type
| Room type | Typical spacing | Why |
|---|---|---|
| Living room, bedroom | ≈ ceiling height | General ambient lighting, supplemented by lamps |
| Kitchen | 4–6 ft | Brighter, more even light for food prep areas |
| Hallway | 6–8 ft | Even light along a narrow, linear space |
| Bathroom | 4–5 ft | Task-oriented lighting in a smaller footprint |
Frequently asked questions
What is the standard recessed lighting spacing rule of thumb?
A common starting rule is to space lights roughly the same distance apart as the ceiling height — an 8 foot ceiling suggests about 8 feet between fixtures. This is a general guideline for even ambient lighting, not a fixed code requirement, and can be tightened for brighter task areas.
Task lighting vs ambient lighting — how does placement differ?
Ambient lighting uses an even grid to light the whole room uniformly, which is what this calculator lays out. Task lighting is placed deliberately over specific work areas — a kitchen island, a reading chair, a vanity — and often sits closer together on its own switch.
How many recessed lights does a kitchen need vs a living room?
Kitchens often use tighter spacing than living rooms, since task areas like counters and islands need brighter, more even light for food prep, while a living room can rely on a wider ambient grid supplemented by lamps. Use a tighter spacing value for a kitchen than for a living room of the same size.
Does spacing change between can lights and LED retrofit fixtures?
Not fundamentally — the same ceiling-height-based rule applies to both, since it's based on even light distribution rather than fixture type. Beam angle and lumen output of the specific LED trim can shift spacing slightly wider or tighter than a traditional can light of the same wattage.