There is no scientific criteria for judging best friend. But there are some key points. First thing is that, there will be a very good rapport between you and your friend. A best friend will always try to empathize with you. In some situations he/she will not be able to help you directly, but he/she will express the willingness to help you. Understanding is the basis of any relation. A best friend will be able to understand your feelings properly. At sometimes, you may seem his/her advice more better than that of your parents. Best friends will never let you down in your tough situations., and they will postively criticize you if you are in the wrong path.

And the most important thing is regarding the depth of friendship. Your best friend will always try to keep in touch with you, irrespctive of his life and busy schedule of work. If you become silent for sometime, your best friend will realize it quickly. Converse is also true. If your best friend stops contacting you for sometime, you will miss him/her badly. This shows the depth of friendship that you have with your friend.