Imperfect Cell Form 1
This form Cell has come out of the larva stage and has shed its skin. He is more powerful than a super saiyan in this form. He is first seen when Piccolo meets him in Nikki Town. He has not absorbed Android 17 or 18 yet in this form.

Imperfect Cell Form 2
In this form Cell has absorbed Android 17 and he is much more powerful now. His Speed, Strength and Appearance have changed. He now has a longer tail. He is first showed in this form when he is fighting Piccolo and the Androids on an island. He still has not abosorbed Android 18 in this form.

Perfect Cell
This form is one of Cells most powerfull stages. He has a tail in this form although it is very small and you cant really see it. His appearance has changed greatly as well. His speed and strength have increased very much. He now has absorbed both of the Androids.

Ultra Perfect Cell
Pefect Cell becomes this form when SSJ Goku uses his instant transmission and takes him to King Kais planet were he blows up. One of Cells cells remain for his regeneration. His power and everything including his appearance have changed. Cell went back to Imperfect Cell Form 2 when SSJ2 Gohan punched him in the stomach, causing him to spit out Android 18. This form of Cell is destroyed by Gohan's Kamehameha wave.