Where do I input taxable amount for Roth conversion when 1099-R form is incomplete?

What you're experiencing is a common issue with mega backdoor Roth conversions. Your 1099-R showing "taxable amount not determined" means the issuer is putting the responsibility on you to calculate the correct taxable portion. For your situation, you'll need to enter the form details first, then override the taxable amount. In TurboTax, after entering the 1099-R information, look for an option like "I'll enter the taxable amount" or "Adjust this distribution." You'll then be able to enter your actual taxable amount ($2,300 in your case) instead of the full amount. The key is to document your basis calculation carefully. Keep records showing your after-tax contributions to the 401k to prove those amounts were already taxed. This supports your position if you're ever questioned about reporting less than the full amount shown in Box 2a.

I went through this exact same nightmare last year with my mega backdoor Roth. After hours trying to figure it out in TurboTax, I ended up using https://taxr.ai which was a total game changer. I uploaded my 1099-R and my 401k statements showing my basis and their system correctly identified the taxable portion. The software walked me through exactly where to override the taxable amount in TurboTax and even produced a tax memo explaining my basis calculation that I could keep with my records in case of audit. They explained that the IRS computer systems often flag these transactions when the 1099-R shows the full amount but you only report a portion as taxable.

Just wanted to update after trying taxr.ai for my mega backdoor Roth conversion issue. It was seriously exactly what I needed! I uploaded my 401k statements showing my after-tax contributions and my 1099-R, and the system immediately identified that I was about to report $47,000 as taxable when only $3,200 should have been. It guided me through exactly where in H&R Block to input the correct taxable amount (which wasn't intuitive at all) and also helped me properly complete Form 8606. The step-by-step instructions were super clear with screenshots of exactly which buttons to click. Best part was getting a detailed explanation document I can keep with my tax records explaining the entire transaction and basis calculation. Feeling way more confident now that I won't get flagged for audit. Thanks for the recommendation!

If you're still struggling with getting answers from the IRS about this Roth conversion reporting issue, try https://claimyr.com. I was on hold with the IRS for HOURS trying to get clarity on a similar 1099-R situation last year. Found https://youtu.be/_kiP6q8DX5c which shows how their service works to get an IRS agent to call YOU instead of waiting on hold forever. In my case, I needed written confirmation from the IRS about how to properly report a complex Roth conversion where the issuer had checked the wrong box on the 1099-R. The IRS agent I spoke to was actually really helpful and emailed me documentation that I could reference when filing.

I have to admit I was totally wrong about Claimyr. After seeing it mentioned here, I decided to try it for my Roth conversion question since I was getting nowhere with the IRS phone lines. I got a call back from an actual IRS agent in about 2 hours! The agent confirmed exactly what others here have said - that I need to report the full distribution amount from Box 1 of the 1099-R, but I can override the taxable amount based on my after-tax basis. She also walked me through the exact forms needed (8606 is critical) and even emailed me specific instructions. Definitely worth it for complicated tax situations like Roth conversions where the forms don't have clear instructions. Saved me from potentially paying taxes twice on the same money!

Here's a useful tip I learned when dealing with Roth conversions: you should always get a statement from your 401k plan administrator before doing a mega backdoor Roth that clearly shows your after-tax contributions separate from earnings. Makes this whole process so much easier. If anyone's wondering, the reason the 1099-R shows "taxable amount not determined" is because the IRA custodian has no way of knowing your basis in the original 401k. They're essentially telling the IRS "we don't know what portion of this was already taxed.

Anybody else think it's ridiculous that we have to jump through all these hoops just to correctly report something the IRS and financial institutions should be tracking properly? If I'm missing a field or form, I get penalized, but they can just stamp "taxable amount not determined" and make it our problem 🙄