# Watts to lumens calculator

 Enter power in watts: W Enter light source: -- select light source -- Tungsten incandescent light bulb Halogen lamp Fluorescent lamp LED lamp Metal halide lamp High pressure sodium vapor lamp Low pressure sodium vapor lamp Mercury vapor lamp Or enter luminous efficacy in lumens per watt: lm/W Luminous flux result in lumens: lm

#### Watts to lumens

What the watt?When buying an incandescent bulb, the watts rating gives consumers a good indication of how bright a bulb is. The more watts, the brighter the bulb.

That rule doesn't apply to LED bulbs, though. An LED that uses 60 watts is in no way comparable to an incandescent bulb that uses 60 watts. In fact, a 60-watt LED just may blind you. LEDs are designed to use less energy and naturally have a lower watt rating. This means it's useless to use watts to determine brightness.

To fix the problem, bulb companies have started using lumens to rate bulbs. This gives you a more accurate indication of how much light to expect from an LED.

Why lumens?Measuring in lumens isn't a new concept designed just for LEDs. It's a rating that's been used for decades as a measurement of how much light a bulb (or anything else) emits.

watts (W) to luminous flux in lumens (lm) calculator and how to calculate.

Energy saving lamps have high luminous efficacy (more lumens per watt).

The luminous flux ΦV in lumens (lm) is equal to the power P in watts (W), times the luminous efficacy η in lumens per watt (lm/W):

ΦV(lm) = P(W) × η(lm/W)