The amount of your Roth contributions are the amount that goes into the Roth, the $1500 total that you state. If the value of those investments from those contributions has declined to $1100, you are able to take a distribution of the entire $1100 without penalty because that is less than the amount of your contributions. You don't keep track of the value of the various contribution amounts, just the total. The fact that the $500 grew to $1000 in the Roth, thus creating earnings, is irrelevant. Only the total contributions and the total distributions matter for that purpose.