The amount of length lost will vary based on your hair type, installation method, and whether you want your ends open or closed.
For Kinky hair, you’ll only loose 1-3 inches in most cases. For Straighter hair with open ends you’ll typically lose 2-4 inches. When you close your ends you’ll typically loose 2-6 inches. And finally, for hair that is brittle or thinned at the ends you will lose more length.