With cheap knives you will get a knife that is not only too short, but they are too light. If you are serious you need to listen to what I have to say as well as some of the guys who have been around throwing for a while. YOU GET WHAT YOU PAY FOR!!!! period!!!!
Ask yourself this question. Would I rather throw a nerf ball or would I rather throw a hard baseball?
It is the same with a knife. Length will give you more control of the blade and weight will give you penetration. You need some of both for a good stick into a target.
The people who sell this tin crap do not care whether or not you are able to stick the knife that you just bought. They deal with the armchair warrior and Mall Ninjas. They want your money and that is it. The guys like myself who make a quaility knife that you can stick, want you to be able to throw a knife and have it stick in the target. That is why you have to pay a little more for quality. There are a few exceptions. Some of the factories are starting to listen to real knife throwers.
Whether you buy a knife from me or one of my friends, I want you to buy the best knife that you can. Even if you have to save a little longer, you will not regret it. I have people who have been throwing my knives for over 20 years. Do yourself a favor and get a good knife designed for throwing.
Bobby