You should have received a form 5498. For a Roth IRA, you would enter the amount in box 5 on the 5498.
If you do not have the 5498, please contact the custodian of your Roth IRA.
Since you will not necessarily have received Forms 5498 from your Roth IRA custodians by the tax-return filing deadline, instead use your year-end account statements to find your year-end balances.
I have after-tax deduction from each of my paycheck to Roth IRA, they got deposit to the same investment account in Fidelity where my pre-tax deduction for 401(k) contribution goes. So the account balance is the composite of both my 401(k) contribution and Roth IRA. I do not receive Forms 5498 from Fidelity, how can I tell how much of the account balance attributed by my Roth IRA? Thanks
@jobseeker95479 , the Roth account is not a Roth IRA. It is a designated Roth account in the 401(k). Because it is not a Roth IRA, nothing about it is reportable on a Form 5498. It's only reported with code AA in box 12 of your W-2.
Your account statements will say how much is in the traditional 401(k) account and how much is in the Roth 401(k) account, but this information is not anything you need to know for your tax return.