Today this question came up on the FastLED Google+ Group, so I decided to actually measure. Turns out, I was surprised to learn it varies quite a lot, depending on which type you actually have.
Type A – Approx 33.5 mA Maximum
My first test was this little board with 64 LEDs.
This is much lower than the 50 to 60 mA per LED budget that’s often mentioned. Here is a macro shot of the actual chip in these LEDs:
Type B – Approx 52.5 mA Maximum
Since the first test turned out so low, I also dug up a small strip of WS2812 LEDs from a project made a couple years ago.
These actually are just above the “normal” 50 mA budget. They also have a distinctly different chip inside.
Both of these were called “WS2812B”, but obviously they are quite different.
Both Types – Approx 1 mA When “Off”
One thing that is nearly identical to both types is the current used by the controller chip when the LED is “off”.
Both are just under 1 mA per LED when just sitting there dark.
This was just a quick test with two WS2812B LED products I had on hand. There may be even more types. But at the very least, hopefully this can give you an idea of how much power you might need for a LED project, depending on which type you actually have.