Download from Github or the Chrome Web Store.
The idea for this plugin came from a comic I saw on abstrusegoose.com and my inclination to have an existential crisis whenever opening a new tab at work.
All you need to do it provide your date of birth and country of residence, and your life expectancy will be found from the United Nations 2010-2015 World Population Prospects, The 2015 Revision.
Every grey dot on the main screen represents one month left in your life, the red dot represents where you are now.
In the settings screen you can set your date of birth and country, and see an exact amount of months left that you are expected to live
Some might find it motivating to see the temporary and fast expiring nature of their own life, and others might find it depressing. If you want to have that feeling when you open a new tab, the extension is available on Github, or in the Chrome Web Store.