This chrome extension enables the use of Checkvist.com to create project estimates.
Currently, I use tags to record how many hours or days a particular item in a checkvist outline will take (e.g. #8h or #2d). This extension will tag parent items with the totals of its children.
The extension options allow you to define your hours and/or days tag format and choose to use them as a prefix or suffix as well as define hour many working hours should equal 1 day. You may also choose for the extension to generate hours tags, days tags or both.
To try it out, download the extension from the Chrome Web Store or clone the source and install in Chrome's Developer Mode.