You can take out whatever you put into your Roth, tax-free, because you already paid taxes on that money.
You can also make tax-free withdrawals on any additional earnings in your Roth IRA unless either of the following are true:
- You're making the withdrawal less than five years after establishing the Roth.
- You're making an early withdrawal (before age 59½) without the exception for death, disability, or the $10,000 first-time homebuyer distribution.
In a nutshell, as long as your Roth has been open for at least five years, you can withdraw as much as you want (if you're 59½ or older) or anything up to the amount you put in (if you're under 59½) without any taxes or penalties.