This is a tutorial showing how to make a cell phone cozy that will fit your phone in crochet. It can use any combination of yarn and needle size and only requires a small amount of yarn.
Gauge is not important as it also shows how to obtain a proper gauge for your work.

My example piece was made from a bulky yarn so it looks big but actually fits quite nicely with the phone display showing through as it should. My tutorial will explain how to get good results with any weight yarn.