What is the difference between lux and lumen?

Lumen measures total light output from a source. Lux measures the light intensity received at a specific surface area. 1 lux equals 1 lumen per square meter.

How many lux do I need for office lighting?

General office lighting requires 300-500 lux at desk level. Detailed tasks like drafting may need 500-750 lux. Corridors and lobbies need 100-200 lux.

Does beam angle affect lux?

Yes, significantly. A narrow beam concentrates lumens into a smaller area, producing higher lux. A wide beam spreads the same lumens across more area, producing lower lux per point.

Back to Academy

Lighting FundamentalsLight Measurement

Lux vs Lumen — What's the Difference?

The foundation of every lighting specification starts here.

4 min LEDWORLD Technical Team 920 views

Why This Matters

Every lighting project starts with one question: how much light do we need? But 'how much' can mean two very different things — the total light a fixture produces, or the light that actually reaches your surface.

Light intensity varies dramatically based on distance and beam angle.

Quick Definition

Lumen (lm) measures total light output from a source. Lux (lx) measures light intensity at a surface. 1 lux = 1 lumen per square meter.

The Analogy

Think of a garden hose. Lumens is the total water flow (liters per minute). Lux is the water pressure at a specific point. A hose spraying wide covers more area but with less pressure at each point. A narrow nozzle concentrates the same flow into a smaller area with more pressure.

Typical Lux Requirements

space	lux	notes
Office workspace	300–500 lux	Task-dependent
Hotel lobby	150–300 lux	Warm, layered
Retail display	750–1500 lux	Product highlighting
Warehouse	150–300 lux	Uniform coverage
Parking area	50–100 lux	Safety focused

Before You Specify

Define the task — reading, display, circulation?

Check reference lux guidelines for the space type

Consider the reflectance of surfaces (dark walls absorb light)

Account for maintenance factor (light output degrades over time)

Use Dialux or a lux calculator to verify fixture quantities

Common Mistakes

Comparing fixtures by lumens alone without considering beam angle

Ignoring surface reflectance — a dark floor absorbs 70%+ of light

Specifying by fixture count instead of required lux at task plane

Not applying maintenance factor — LEDs lose 10-20% output over life

Related Tools

Lux Estimator

Frequently Asked Questions

Next Topic

Beam Angle Explained

Beam Angle Explained Ip Vs Ik Ratings

luxlumenmeasurementfundamentalsspecification

Planning a light measurement lighting project?

LEDWORLD has completed 6,000+ lighting projects across the UAE and GCC. Our team can handle everything from lighting design to supply and installation.