A backdoor Roth rollover can typically be done very quickly. Once you have a traditional IRA set up, you will need to make an after-tax contribution to the account. You could then do the conversion almost immediately in most cases. A custodian (the bank or brokerage holding your IRA) will probably require that the conversion isn’t made until the money contributed to the traditional IRA clears. Typically, the conversion can be completed within just a couple of days. It’s always best to ask your custodian what the process is for creating a backdoor Roth IRA to avoid delays.