Incandescent, halogen, CFL and LED: what replaces what

Wattage never measured brightness. It measured how much power a filament drew. Because every incandescent bulb was about as inefficient as every other, watts became a usable shorthand for light output, and two generations of buyers learned to shop that way. LEDs broke the shorthand completely. A nine-watt LED and a sixty-watt incandescent put out roughly the same light, so the only number that still means brightness is lumens.

Lumens is the figure to shop on, and it is printed on the Lighting Facts label on every bulb sold in the US. The equivalent wattages above are typical values rather than guarantees, because efficiency varies by manufacturer, by color temperature and by color rendering. A 90+ CRI lamp usually draws a little more power for the same lumens, and that is a trade worth making anywhere finishes, food or faces are on display.

Three other things matter as much as brightness when you swap. Check the bulb is marked dimmable and appears on your dimmer manufacturer's compatibility list. Check it is rated for enclosed fixtures if it is going into a sealed globe, because trapped heat shortens driver life. And match the location rating for damp or wet spaces the same way you would match the fixture.