401k Rollover- Can I do backdoor Roth?

[SeaBehr]

I'm leaving a former employer who I had a 401k with about $40k in it. I've been reading that it's best to convert it to my IRA which I have with Vanguard, however I use that same IRA to fund my backdoor Roth. Can I have rollover my 401k to my IRA and still do the backdoor? Should I create a separate IRA to rollover the 401k to? Can I rollover the 401k and do a backdoor Roth in the same year? Does having that rollover money in my IRA prohibit me from doing a backdoor Roth in subsequent years?

[Peds]

you would rollover the 401k to a IRA.
then you would have to convert it to a rIRA or deal with prorata.

this all depends on marginal rate and new employer retirement plan options.

[spiritrider]

Pre-tax balances in all traditional, SEP and SIMPLE IRA accounts are included on Form 8606 Line 6 and will be used for pro-rata tax calculation with any non-deductible basis.

There is no need to rollover the prior employer's 401k to an IRA and would generally be a bad idea if you want to do back door Roths.

Unless the 401k is terribly expensive why not just leave the assets there indefinitely. If you have a new employer plan with decent investment options/costs you likely can rollover directly from the previous to the current employer's plans.