To be 100% tax-free, a Roth distribution must meet two criteria:
1. The account has been open for 5 tax years (which you've met).
2. You must be age 59½ or older, disabled, or using it for a first-time home purchase ($10k limit).
If you are UNDER 59½, only your contributions are tax-free. If you withdrew more than you put in, the excess (the earnings) is taxable.
TurboTax needs you to enter your "Roth Basis" to cancel out the tax. Follow these steps:
You must enter the total amount of money you have ever contributed to your Roth IRAs over your lifetime.
For example, if you withdrew $10,000 but you have contributed $15,000 over the years, your basis is $15,000. Once you enter this, TurboTax will see that you are just taking back your own "already-taxed" money, and the tax will disappear from your 1040.
You should also check your 8606. Go to Tax Tools -> Tools -> View Tax Summary -> Preview my 1040. Look for Form 8606, Part III.
Line 22 should show your basis.
Line 25 should show $0 taxable.