Get your taxes done using TurboTax

All you need to do is enter your Form 1099-R and answer the follow-up questions:

1. Click "Federal Taxes" on the top and select "Wages & Income"
2. Click "I'll choose what to work on"
3. Scroll down and click "Start" next to "IRA, 401(k), Pension Plan (1099-R)" 
4. Enter your Form 1099-R (with code G)
5. On the "Did you move this money from a 401(k) to a Roth 401(k)?" screen answer "Yes"
6. On the "Rollover 401(k) to Roth 401(k)" screen answer "Yes" (this should have the amount from box 5 already entered)

You can check Form 1040 line 5a has the distribution amount and 5b has the taxable amount (it should be $0 since you only converted after-tax funds).