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LuxPlan
96 sq ft · 150 lux target

8×12 living room:
6 lights

6 fixtures A 8×12 ft living room (96 sq ft) needs approximately 6 recessed lights at 800 lumens each — about 4,181 lumens in total — laid out 3 across by 2 deep.

Space them 4 ft apart along the 12 ft wall and 4 ft apart along the 8 ft wall, starting 2 ft from the end walls.

Fixtures6at 800 lm each
Total lumens4,181to hit 150 lux
Spacing4′× 4′ apart
Wall offset2′from the end wall

The ceiling plan

Drawn to scale, with each fixture at its computed position and the pale circles showing roughly where each one lands on the working plane.

12 ft 8 ft 3 across × 2 deep · 4 ft × 4 ft apart · 2 ft from the end walls

Same room, different fixtures

If you have already chosen a fitting, read across from its lumen output.

Fixture outputRough equivalentFixtures neededSuggested grid
450 lm 40 W incandescent 93 × 3
650 lm 50 W incandescent 63 × 2
800 lm 60 W incandescent 63 × 2
1000 lm 75 W incandescent 42 × 2
1200 lm 100 W incandescent 42 × 2

Fewer, brighter fixtures give more contrast; more, dimmer fixtures give flatter, more even light. Both rows deliver the same total.

How the 6 was calculated

Target illuminance for a living room150 luxpublished range 150–300 lux
Floor area8.9 m²96 sq ft
Mounting height above the working plane8 ft8 ft ceiling, measured to the floor
Room index0.6(L × W) ÷ (Hm × (L + W))
Utilisation factor0.4from the room index, light surfaces
Maintenance factor0.8dirt and lamp depreciation
Lumens required4,181 lm150 × 8.9 ÷ (0.4 × 0.8)
Fixtures at 800 lm6delivering about 172 lux

A living room is lit for atmosphere as much as visibility. The figure here is the general ambient layer — reading corners want a lamp, not more downlights.

Other ceiling heights

CeilingFixturesGridSpacingMax spacing
8 ft63 × 24′ × 4′10.4′
9 ft63 × 24′ × 4′11.7′
10 ft63 × 24′ × 4′13′
12 ft63 × 24′ × 4′15.6′

Questions

How many recessed lights do I need for a 8x12 living room?

About 6 fixtures at 800 lumens each, arranged 3 across by 2 deep. That gives roughly 172 lux across 96 square feet, against a target of 150 lux for a living room.

How many lumens does a 8x12 living room need?

Roughly 4,181 lumens in total. That comes from 150 lux over 8.9 m², divided by a utilisation factor of 0.4 and a maintenance factor of 0.8 — the light that never reaches the working plane has to be paid for up front.

How far apart should the lights be in a 8x12 room?

4 ft apart along the 12 ft wall and 4 ft apart along the 8 ft wall, with the outer row about 2 ft in from the end walls — half a spacing. With a 8 ft ceiling the maximum sensible spacing is around 10.4 ft before the floor starts to show scallops.

Does the ceiling height change the answer?

Yes, in two ways. A higher ceiling spreads each fixture's light over a wider area, so fixtures can sit further apart — but it also drops the light level reaching the floor, so a taller room generally needs more total lumens. At 8 ft the room index works out at 0.6, giving a utilisation factor of 0.4.

Computed with the lumen method — see how it works and where it is weak. Planning guidance only, not an electrical design. Fixture counts are a starting point — follow your local wiring rules and use a licensed electrician for the installation.

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