This will give the age of the most recent common ancestor of a set of taxa, or stretch an input tree, based on available time-calibrated trees. It is still actively in development, so it may break at times. Currently it mostly has mammals in the database, but we are actively adding taxa. See the FAQ page for more info on this project, and the Phylotastic page for more info on the overall hackathon, of which this was just one outcome.
Note source code is available at https://bitbucket.org/bomeara/datelife
We use the PhyloOrchard R package to store trees; you can install it by doing