How do I use total lumens to pick fixtures?

Divide total lumens by the output per fixture or bulb to estimate how many you need (e.g., 7,500 lumens ÷ 800-lumen bulbs ≈ 9–10 bulbs).

Should I adjust for dark walls or high ceilings?

Yes. Dark finishes or tall ceilings absorb more light—add 10–30% more lumens.

What about color temperature?

This tool focuses on brightness. Choose color temperature (e.g., 2700K vs 4000K) based on room mood and task needs.

Does this account for daylight?

No. Reduce the target if the room gets strong natural light, or leave as-is for nighttime needs.

Can I use foot-candles instead?

Lumens per sq ft is equivalent to foot-candles. The values here map to typical foot-candle guidance by room type.

construction calculator

Lighting Lumens Calculator

Estimate total lumens needed for a room based on square footage and room type.

Results

Recommended lumens per sq ft: 20
Total lumens needed: 3,000

How to use this calculator

Enter room square footage.
Select the room type to set lumens-per-square-foot.
See the total lumens target; divide by bulb/output to plan fixtures.

Inputs explained

Room area: Square footage of the space to light.
Room type: Sets an appropriate lumens-per-sqft target for that space.

How it works

Each room type has a suggested lumens-per-square-foot (foot-candle) range. We apply a representative value and multiply by room size.

Formula

Total lumens = Room area × Lumens per sq ft (by room type)

When to use it

Planning lighting for kitchens, offices, or workshops with higher brightness needs.
Estimating how many fixtures or bulbs you need by dividing total lumens by fixture output.
Checking if existing lighting is underpowered for the room’s purpose.

Tips & cautions

Task areas (kitchen counters, desks) may need more focused lumens—add task lighting as needed.
Higher ceilings and darker finishes may warrant bumping lumens up.
For warm/ambient spaces, stay on the lower end; for task work, move higher.
Uses typical guideline values; actual needs vary by finishes, ceiling height, and preference.
Does not account for daylight or fixture efficiency; adjust as needed.
Single-room snapshot; whole-home plans may need layered lighting design.

Worked examples

150 sq ft kitchen

Kitchen target ≈ 50 lumens/sq ft
Total ≈ 150 × 50 = 7,500 lumens

120 sq ft bedroom

Bedroom target ≈ 20 lumens/sq ft
Total ≈ 120 × 20 = 2,400 lumens

Deep dive

Estimate lighting needs by entering room size and type to see recommended lumens per square foot and total lumens.

Use it to plan fixtures and bulbs for kitchens, offices, living rooms, and more.

FAQs

How do I use total lumens to pick fixtures?: Divide total lumens by the output per fixture or bulb to estimate how many you need (e.g., 7,500 lumens ÷ 800-lumen bulbs ≈ 9–10 bulbs).
Should I adjust for dark walls or high ceilings?: Yes. Dark finishes or tall ceilings absorb more light—add 10–30% more lumens.
What about color temperature?: This tool focuses on brightness. Choose color temperature (e.g., 2700K vs 4000K) based on room mood and task needs.
Does this account for daylight?: No. Reduce the target if the room gets strong natural light, or leave as-is for nighttime needs.
Can I use foot-candles instead?: Lumens per sq ft is equivalent to foot-candles. The values here map to typical foot-candle guidance by room type.

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Guideline-level sizing only. Verify with fixture specs and adjust for finishes, ceiling height, and daylight. Consult a lighting pro for detailed layouts.