Lighting

Room Lumen Calculator

Enter your room size and type to get the exact total lumens and foot-candle target it needs - then see how many LED bulbs or fixtures deliver that light.

Light needed

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Total lumens for this room.

Room area
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Foot-candle target
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Bulbs needed
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Enter your room to begin.

How much light a room really needs

Watts measure energy, not brightness - lumens measure the light you actually see. Lighting professionals specify a foot-candle level for each room and task (a foot-candle is one lumen per square foot). Multiply that target by your room's area and you get the total lumens the space should receive.

Foot-candle targets by room

Relaxed spaces such as bedrooms and living rooms sit around 15–20 foot-candles. Work surfaces - kitchens, offices, bathrooms and laundry - climb to 35–50 because you're reading labels, chopping, or grooming. Circulation spaces like halls need only about 10. Selecting the room above applies the right target automatically.

Turning lumens into fixtures

Divide the total lumens by the output of one bulb to get a count, then spread that light across several fixtures and layers rather than a single bright source. Even, layered light - ambient plus task plus accent - always reads better than one glaring ceiling fixture.

Tip: dimmers let one layout serve both bright task work and low-key evenings, so size for the higher target and dim down.

Frequently asked questions

How many lumens do I need for a room?

Multiply the room area in square feet by the recommended foot-candle level for that room type. A 12 × 15 ft (180 sq ft) living room at 20 foot-candles needs about 3,600 lumens; a kitchen at 35 foot-candles needs about 6,300. This tool does the math and converts it to bulbs.

What is a foot-candle?

A foot-candle is one lumen of light spread over one square foot of surface. Lighting standards specify foot-candle targets per room and task; total lumens needed = area × foot-candles.

How many lumens is a 60-watt bulb?

About 800 lumens. A 40-watt equivalent is ~450 lumens, a 75-watt ~1,100, and a 100-watt ~1,600. Pick your bulb output above and the tool tells you how many you need.

Should all the light come from one fixture?

No. Spread the total across layers - ambient (ceiling), task, and accent lighting. The bulb count is a total budget to distribute, not a single fixture size.

Is my room data stored?

No. All calculations happen locally in your browser.

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