We regularly get the question "How do you distinguish real from fake LEGO?"

A few months ago I was sold a bag of Technic parts and even though I've been in the LEGO scene for about 5 years now I couldn't immediately tell that I had had a bunch of fake parts made deliberately to deceive me ! I have since learned that knowing the LEGO system bricks did not prepare me with the skills to identify Technic parts. I was pleased to see that Steve Tan has put together this guide to help distinguish the difference between LEGO and non-LEGO parts.

Fake Lego vs. Real Lego (updated May 5, 2019)

Common parts of LEGO Technic How to tell the difference by checking and comparing the parts in detail

I recently had the chance to compare a batch of fake Lego with real Lego. Comparison is only done for Lego Technic pieces because that's what I have. Conclusions were drawn based on my own limited understanding, as well as the pieces I have, with a lot of help from Sariel's Lego Technic book.

I have a little knowledge of plastic injection molding and will use some terminology to explain the differences.

Gating - Where the mold (hot runner or normal runner) separates from the part.

Cavity - The part of the injection molding tool that is attached to the machine.

Core - The other part of the injection molding tool that corresponds to the cavity.

Slide – Another part of the tool that moves in a different direction from the core and cavity, to make undercuts.

Parting Line - A visible line where the core/cavity/slide separates from the tooling. Well-designed and well-maintained molds produce very minimal parting line.

Flashing - Excess material caused by incomplete/mismatch of the tool parts.

There will probably be some mistakes, but please let me know so we can all learn from them.

This is not a comprehensive guide and there will be other ways in which fake Lego can differ from the real Lego.

Fake Lego vs. Real Lego: Summary



For most Lego Technic parts, it is possible to distinguish fake from real Lego, as the Lego logo is usually molded onto the real parts.


Some differences (low quality fakes) are very obvious, while others (higher quality fakes) require more research before the differences can be seen.


Axles are the biggest problem, as some real Lego axles do not have the Lego logo molded on them.


For some components the differences can only be seen during a comparison. By themselves, the fake Lego parts won't look fake unless you know the real Lego part very well.


Note that all of these comparisons are based on my own observations, using the parts I have. I'm sure there are other differences from other fake Lego parts as there are many different sources of fake Lego parts from different molds.


The reason I created this comparison guide is to help true Lego fans, to ensure that they are getting genuine Lego parts when purchasing from second-hand sources. It is certainly not intended to promote fake Lego.