A very quick google would have given your the answer:

Ethereum creator Vitalik Buterin has proposed an answer to one of Ethereum’s more common questions — whether or not the cryptocurrency’s coin supply should ever be capped.  In an Ethereum Improvement Proposal (EIP) on April 1st, Buterin wrote:

I recommend setting MAX_SUPPLY = 120,204,432, or exactly 2x the amount of ETH sold in the original ether sale.