If you want to regulate your sleep or develop a sleep pattern, napOleon has a solution for you. This extension records your sleep duration to help you have a clear view of how much time you spend sleeping. It works by providing you with a time-based bank with specifically allotted hours where your naptime will be deducted from. You may select your plan of choice—casual, regular, and productive—each having differing given naptime with starting buffers. The bank refreshes everyday so that you can compare your daily results. 

To use the extension, just click the "Start Napping" button when you're about to sleep and hit it again as soon as you wake up.