How bright is 15000mcd?

Question

I'm buying leds for my car interior and i need something to compare the brightness with since I'm buying them off ebay.

Answer 1

mcd is an abbreviation for millicandela which is a unit of luminous intensity.  For comparing lamps you typically use luminous flux which is in the units of 'lumens'.  To convert between the two measures you need to know the "radiation angle" or "beam angle" of the lamp (the full vertex angle of the emission cone) which should be specified with the LEDs you are looking at buying [sometimes specified as 2θ^(1/2)]

Here is a website that can help with the conversion from 'mcd' to 'lumens':  http://led.linear1.org/lumen.wiz

"As a point of reference, a standard 100W light bulb typically is rated at around 1,700 lumens in North America, and around 1,300 lumens in 220V areas of the world."