Lumens Calculator

Estimate total lumens, lumens per fixture, lumens per square foot, LED wattage, fixture quantity, room brightness, and lighting energy use. This calculator helps plan lighting for rooms, garages, shops, offices, warehouses, and outdoor areas.

Calculate Lumens

Total lumens = lumens per fixture × fixture quantity. Lumens per square foot = total lumens ÷ room area.
Your result will appear here.

How the lumens calculator works

Total lumens:
The calculator multiplies fixture lumens by quantity or totals detailed fixture rows.

Room brightness:
Total lumens are divided by room area to estimate lumens per square foot.

LED wattage:
Lumens per watt are used to estimate how many watts are needed for a target lumen level.

Why use a lumens calculator?

A lumens calculator helps estimate how bright a room or space will be before buying fixtures or bulbs.

It can help with bedrooms, kitchens, garages, shops, offices, warehouses, exterior lighting, LED upgrades, fixture planning, and energy cost estimates.

What your result means

Your result shows total lumens, adjusted lumens, target lumens, lumens per square foot, fixture count needed, estimated LED watts, total wattage, monthly kWh, monthly cost, yearly cost, and detailed fixture row totals.

Lumens calculator formulas

Frequently asked questions

What are lumens?

Lumens measure the amount of visible light a bulb or fixture produces. More lumens usually means brighter light.

How many lumens do I need for a room?

Multiply the room area by your target lumens per square foot. General rooms may use 30 to 50 lumens per square foot, while task areas may need more.

How do I convert watts to lumens?

Multiply watts by lumens per watt. For example, a 10W LED at 100 lumens per watt produces about 1,000 lumens.

Are lumens better than watts for choosing bulbs?

Yes. Lumens tell you brightness, while watts tell you energy use. LED bulbs can produce the same brightness with fewer watts.