The Investment Scientist

Roth IRA conversion examples

Posted on: January 17, 2010

There is one important rule to keep in mind when it comes to converting a traditional IRA to a Roth IRA – you need to pay federal income taxes on any portion of the conversion that you haven’t already paid taxes on.

Example 1

For example, let’s say you started to fund traditional IRAs in 2006 and by 2010 you’ve got $20,000 in your account.  Furthermore, let’s say this account consisted of four years of $4,000 non-deductible contributions – a total of $16,000 in non-deductible contributions and $4,000 in account growth.

In this example, you’d need to pay income taxes on the $4,000 in fund growth when you convert to a Roth IRA.  But the good news is you’ll never have to pay income taxes on this account again.

Example 2

In this second example, let’s assume that you funded the that same traditional IRA with before-tax dollars – meaning you were able to take a deduction on your tax return for the money placed in the traditional IRA.

In this example, you haven’t paid income taxes on any of the money in the account, so when you convert it to a Roth IRA taxes are owed on the entire account balance.  In this case you’d have to pay income taxes on all $20,000 in your fund.

Example 3

If you have an existing traditional IRA (with tax-deductible contributions) and you start to fund a non-deductible IRA, then you need to be aware that tax rules state that any conversion is done on a pro-rata basis.  Let’s say you had $100,000 in a regular IRA and you had $25,000 in a non-deductible IRA.

If you wanted to convert $25,000 to a Roth, then you’d owe taxes on $20,000 because the pro-rata share of your non-deductible contributions is only $5,000.

Get my white paper: The Informed Investor: 5 Key Concepts for Financial Success.

4 Responses to "Roth IRA conversion examples"

I contributed to a traditional ira (after tax) some years ago. Now (year 2010) I converted it to a roth. Where do I show that conversion on my 2010 tax form? I have already paid taxes on it, so the 8606 doesn’t seem to work. That seems to apply only to the past year.


Any after tax contributions you made to the traditional IRA should be reported in box 5 of the 1099 you receive reporting the conversion to Roth. The after tax contributions are basis and you will not be taxed on that portion of the conversion. Report the net taxable conversion on line 15 on the front page of your 1040. Hope this helps.

I converted my traditional IRA to a Roth in 2010. By income limits, I can only contribute to a nondeductible traditional ira in 2011. Can I again convert this money to a roth in 2011 as well? How much time must one wait to do this (if it is allowed). THX. DA

Yes. Immediately. For more information, check out this article on Vanguard website:

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s


Michael Zhuang is principal of MZ Capital, a fee-only independent advisory firm based in Washington, DC.


%d bloggers like this: