Special thanks to /u/Carlitocarlin on Reddit for the data!
Is this number exact?
Not Quite. The multiplier used to evolve your Pokémon isn't the same everytime you evolve a Pokémon. There is still a bit of a random luck factor. For the multiplier used on this site, we use the mean of the user submitted data on the spreadsheet linked here. So you should only use this CP number as an estimate of your evolved Pokémon's CP.
How was this data collected?
This data was collected by Reddit user /u/Carlitocarlin. Cariltocarlin created a Google Docs spreadsheet that displays data he collected by Pokémon Go users.
Is the list of Pokémon complete?
Yes! When we first launched we were missing data for a couple Pokémon, but we have since updated the site to contain their multipliers too! If a Pokémon isn't listed it is because they do not evolve.