Home & Garden Calculators

The number depends on room area, ceiling height, and your target brightness. A common rule is to allow 20 lumens per square foot for general living spaces. Divide the total lumens needed by the output of one fixture to get your fixture count. For example, a 12×14 ft living room (168 sq ft) at 20 lm/sq ft needs 3,360 total lumens — roughly 4 fixtures at 800–900 lumens each. Use the Recessed Lighting Calculator above to get a precise count for your room.

The industry rule of thumb is to space recessed downlights at a centre-to-centre distance equal to roughly half to two-thirds of the ceiling height. For a 9 ft ceiling that means fixtures spaced 4.5–6 ft apart. Wall offset (the distance from the wall to the nearest fixture) should be approximately half the fixture spacing — typically 2–3 ft for a 9 ft ceiling. The calculator applies the 0.6 × ceiling height formula automatically.

Lumens measure the total light output of a fixture. Foot-candles (fc) measure how much of that light actually falls on a surface — specifically, 1 lumen per square foot. A brighter fixture produces more lumens, but how many foot-candles reach your work surface also depends on ceiling height, beam angle, and fixture spacing. General living areas typically need 10–20 fc; kitchens and offices need 30–50 fc.

4-inch fixtures suit accent lighting and task lighting over counters, and work best on low ceilings (8 ft or below). 6-inch fixtures are the most common choice for general ambient lighting and suit ceilings from 8–10 ft. For ceilings above 10 ft or large open spaces, 8-inch fixtures provide better coverage and throw. A quick rule of thumb: fixture diameter in inches ÷ 2 = minimum distance in feet from the wall to the first fixture.

Bedrooms typically need 10–20 lumens per square foot for comfortable ambient lighting. A 12×12 ft bedroom (144 sq ft) needs roughly 1,440–2,880 total lumens — around 2–4 fixtures at 700–900 lm each. Always use dimmer-compatible LED fixtures in bedrooms so you can lower the brightness for relaxing without changing the fixture count.

Yes — kitchens require 30–50 foot-candles of task lighting over work surfaces. Select ‘Kitchen’ as the room type in the calculator and it will apply the higher lumen target, recommending a greater fixture count and tighter spacing compared to a living room. For best results, supplement recessed ceiling lights with dedicated under-cabinet lighting directly over countertops.