The general rule of thumb (this varries for some species), but it does apply to Eclectus is this....
When looking at the beak closed from the side the tip should not extend past the bottom of the lower beak where it meets the jaw....
That being said, for beak work I strongly recomend a quality vet. I do beak work, and it has taken years to learn the structure and what is too long or mis shaped for what species. There is a lot more to trimming beaks then just cutting the tip off, and if done wrong it can cause the beak to grow incorrectly. The best advice is lots of different toys so a bird can keep the beak in top shape naturally.
Thanks! I would also like to ask the if the beak is already too long is it possible to cure it with a lot of toys etc... will it get shorter if i give him more opportunities to use its beak.
2 Budgies, 3 Cockatiels, 6 GCC'S, 2 Crimson Bellie Conures, 9 Sun Conures, 2 Major Mitchells, 12 Eclectus parrots of various ages, 2 BF Amazons, 2 Hahn's Macaw's, 1 Red Tail Black Too
It will also depend on what sub-species you have. But just by my own eclectus & to my knowledge all eclectus have what appears to be an elongated top beak. Especially the males. I have posted a link for you to view. You will be able to compare.
That said your eclectus is only a young bird & the chance of it's beak to be over grown is almost nil. Only if he has a health issue would that be possible. These include, Liver Disease, Lack of natural light, Nutritional Imbalances, Lack of minerals/Natural Grooming Aids.
I do not recommend any beak trimming unless it is absolutely necessary. I much prefer chewing toys to trim their beak naturally.