How to track historical contribution basis when rolling over a Roth 401k
Uncertainty about historical contribution basis makes it difficult to figure out how to sum up past contributions across accounts or determine tax implications when rolling over or withdrawing early. Without clear records, people are left guessing whether methods like summing W2 box 12 code AA values are reliable, or how the five-year rule and age 59.5 thresholds apply to their withdrawals.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
Found another way around this?
Share your steps and trade-offs so fellow engineers don't have to reinvent the wheel. No account required.
- 1Summing historical W-2 box values or 1099-R formsDid this help you?
- 2Relying on plan trustee statements upon rolloverDid this help you?
- 3Leaving the money in the account to continue growing tax-freeDid this help you?
- 4Withdrawing from other taxable or tax-deferred sources firstDid this help you?
- 5converting up to the 12% bracket over timeDid this help you?
- 6researching optimal Roth conversion strategiesDid this help you?
- 7converting current traditional IRA balances and paying the taxDid this help you?
- 8rolling traditional IRA balances into an active employer-sponsored 401kDid this help you?
- 9working with a financial professionalDid this help you?
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“Could you help clarifying the tax implication for taking out from Roth at age 59 1/2?”source ↗
“I am a little fuzzy on the 5 year rule. Does 2k gain from last year's contribution get taxed?”source ↗
“Based on my account composition and RETIRED status - would I be subjected to the pro rata rule?”source ↗
“Once I quit/retire and roll my Roth 401k funds into a Roth IRA, am I able to withdraw my contributions tax/penalty free prior to age 59.5? Does it work like Roth IRA contributions at that point?”source ↗
“For determining contributions, can I sum my W2, box 12, code AA values over the years I've contributed? Is that an unambitious and reliable method to ascertain contributions or am I missing something?”source ↗
“It's too late for me to "clean it up" as I am no longer working? Do I have the option to rollover my Rollover IRA back into the trad 401k that I am still maintaining?”source ↗
“This is what is making me so upset! It doesn't make sense”source ↗
“I've been trying to understand it all day and the whole concept baffles me.”source ↗
Where this came up
People with this problem also raised
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- 13When is the best time to do a retirement account rollover?
- 4How do 401(k)s and retirement accounts actually work?
- 15Should I max my IRA or 401k first after a raise?
- 4How to handle 401(k) contributions and employer matches when changing jobs