Early non-exempt withdrawal from a Roth-IRA results in a "10% penalty". A 10% penalty on what amount: The amount withdrawn? The remaining balance of the Roth IRA? Both?
Ok, finally got this one figured out--pardon my earlier answer.
You owe a 10% penalty and income tax (not capital gains tax) on any gains you take out. That is, any amount you take out that is above the amount you contributed to the account.
Say your tax rate is 28% and you have an account with $15,000 in it, $5,000 of which is gains. If you take out $11,000, you owe the government 10% as a penalty plus 28% as tax of the $1000 you took out that was gains. So you owe $380.
Another example, if you take out $10,000 and you only had $5,000 of contributions in the account, then you owe 10% plus your tax rate (say, 20%) on the $5,000 you took out that was gains. That totals $5,000*(.10+.20)=$1,500. Note that you may need to provide proof of your contributions. Not sure whether the contribution amount applies to that Roth or all your Roth accounts...someone can tell us in the comments.
Bottom line: best to leave gains in there. Limit your early withdrawals to your contribution total only.
Unless an exception applies, most distributions from a Roth IRA before the owner reaches age 59 1/2 will be subject to an "early withdrawal penalty" of 10% on the amount of the distribution. Be very careful NOT to confuse the early withdrawal penalty with the taxes imposed on a non-qualified distribution. A non-qualified distribution imposes an ordinary income tax on the distribution, but the early withdrawal penalty will be imposed in addition to that tax.
If, for example, you are in a 20% tax bracket, withdrawing say $10,000 will cost $3,000 in penalty and taxes.