I've contributed $5500 to a Traditional IRA, planning for that to be tax deductible. My employer didn't have a 401k plan earlier in the year, but will have one implemented before the end of this year (2014), and I'm planning to probably contribute as much as I can to it.
Depending on my income (based on the table here), this would make my $5500 IRA contribution not tax deductible.
Wikipedia says that Traditional IRA "withdrawals at retirement are taxed as income (except for those portions of the withdrawal corresponding to contributions that were not deducted)".
My question is: Since my non-deductible IRA contributions are in the same account as deductible contributions, how would it be determined in retirement how much of which withdrawals are taxed? This seems a bit complicated, as the account is appreciating in value, and additional contributions will be made in the future.
Also: Should I be considering other options (like converting the non-deductible contribution to a Roth IRA)?