LED Lighting Glossary: Lumens, Lux, IP, SAE & More

Quick answer: below are the LED lighting terms you'll run into when choosing lights — lumens, lux, candela, color temperature, IP rating, SAE/DOT/ECE and more — each explained in plain language by the SC LED team.

Lumens

The total amount of light a source emits. More lumens does not always mean more usable light — beam pattern and optics decide how much actually reaches your target.

Lux

Light intensity landing on a surface (lumens per square meter). It tells you how bright the light actually is on the target at a given distance.

Candela

Luminous intensity in a specific direction. It's the best single predictor of how far a light will throw down the trail.

Color temperature (Kelvin)

The color of the light. 3000K is warm yellow; 5000-6500K is daylight white, which gives the best contrast and lowest eye fatigue off-road.

CRI

Color Rendering Index — how accurately colors appear under the light. Higher CRI means truer, more natural colors.

IP rating (IP67 / IP68)

Resistance to dust and water. IP67 is dust-tight and water-resistant; IP68 is dust-tight and submersible — ideal for off-road.

SAE J581 / J583

US standards for auxiliary lamps: J581 covers driving lamps, J583 covers front fog lamps. Street-legal auxiliary lights carry these marks.

DOT

A US Department of Transportation mark on the lens, declaring the light meets FMVSS 108 for on-road use.

ECE

European-type approval standard for vehicle lighting, also followed in many Latin American countries.

TIR optics

Total Internal Reflection — a precision lens around each LED that focuses light forward for more reach and a cleaner beam than a reflector.

Beam pattern

The shape of the projected light: spot (long, narrow), driving (balanced), flood (wide, close), fog (low, wide) and combo (spot + flood).

DRL

Daytime Running Light — a low-power light (often amber) that improves daytime visibility and adds a styling signature.

Operating voltage (12-32V)

The voltage range a light accepts. A 12-32V range fits cars, trucks, UTVs and heavy vehicles alike.

Still unsure which light fits your needs? See our guide to choosing LED lights or browse Off-Road and On-Road.