Element ID
The LEGO element ID is the combination of LEGO Design ID and LEGO Color ID.
Contents
Description
davee123 at BrickSet describes it this way (using LEGO Part Number for element ID):
Finding the Element ID
Distinguishing Types of Numbers
If you are unsure about whether a number is a LEGO element ID or a part number, a good way to tell is the number of digits. LEGO element ID’s have 6 or 7 digits, while part numbers typically have 4 or 5 digits. Also part numbers can often be found molded on the physical piece itself in a tiny font (smaller than the word “LEGO” on a stud.)
Using Instruction Booklets
LEGO instruction booklets which list the set inventory usually list the LEGO element ID next to the image of the element.
Using BrickLink
Note: sometimes the same color is listed multiple times. This indicates that the color was issued, discontinued, and reissued a number of times. To the right of the element ID should be another number. This will tell you which entry came out before others. For example, you can have three entries. They will have a 1, 2, and 3 to the right of their ID. This means the one labeled “1” is the oldest and “3” is the newest since it was issued last. In cases like these, it is best to only take the element ID that is the newest when using it to deal with LEGO. Otherwise, their system will just tell you that the piece is discontinued.tb
Finding Pictures of Elements
You can enter the element ID in the BrickLink search box and for most elements it will take you to the page for that part and tell you what color the ID number codes for. This depends on BrickLink contributors adding that element ID to the BrickLink catalog, so new parts might not be in there yet. Once you’re on the BrickLink page for the part, you can get small images in different colors.